Mercury, Mercury Marine, MerCruiser, Mercury MerCruiser, Mercury
Racing, Mercury Precision Parts, Mercury Propellers, Mariner,
Quicksilver, #1 On The Water, Alpha, Bravo, Pro Max, OptiMax,
Sport-Jet, K-Planes, MerCathode, RideGuide, SmartCraft, Zero
Effort, M with Waves logo, Mercury with Waves logo, and SmartCraft
logo are all registered trademarks of Brunswick Corporation.
Mercury Product Protection logo is a registered service mark of
Brunswick Corporation.
4.3, 5.0 MPI & SEACORE 4.3, 5.0 MODELS INSTALLATION
MANUALModels CoveredAlphaModels covered 4.3 MPI 5.0 MPI Serial
Number 1A300000 and above
BravoModels covered 4.3 MPI 5.0 MPI SeaCore 4.3 SeaCore 5.0
1A300000 and above Serial Nnumber
NoticeNOTICE After completing installation, these instructions
should be placed with the product for the owner's future use.
NOTICE Predelivery preparation instructions must be performed
before delivering boat to the product owner.
Notice to Boat Manufacturer/InstallerThroughout this
publication, dangers, warnings, cautions, and notices, (accompanied
by the International Hazard Symbol) are used to alert the
manufacturer or installer to special instructions concerning a
particular service or operation that may be hazardous if performed
incorrectly or carelessly. These safety alerts follow ANSI standard
Z535.62006 for product safety information in product manuals,
instructions, and other collateral materials. Observe Them
Carefully! These Safety Alerts alone cannot eliminate the hazards
that they signal. Strict compliance to these special instructions
when performing the service, plus common sense operation, are major
accident prevention measures.
! DANGERIndicates a hazardous situation which, if not avoided,
will result in death or serious injury.
Page i
2007 Mercury Marine
90-899883178 NOVEMBER 2007
! WARNINGIndicates a hazardous situation which, if not avoided,
could result in death or serious injury.
! CAUTIONIndicates a hazardous situation which, if not avoided,
could result in minor or moderate injury.
NOTICEIndicates a situation which, if not avoided, could result
in engine or major component failure. IMPORTANT: Identifies
information essential to the successful completion of the task.
NOTE: Indicates information that helps in the understanding of a
particular step or action. NOTE: Refer to the appropriate Mercury
MerCruiser Product Applications Manual for application
recommendations. This installation manual has been written and
published by Mercury MerCruiser to aid the boat manufacturer (OEM)
in the installation of the products described herein. It is assumed
that these personnel are familiar with marine product installation.
Furthermore, it is assumed that they are familiar with, if not
trained in, the recommended installation procedures of Mercury
MerCruiser product. We could not possibly know of or advise the
marine trade of all conceivable installations and of the possible
hazards and/or results of each installation. Therefore, the OEM is
responsible for any installation that does not fulfil the
requirements of this manual. It is the responsibility of the boat
manufacturer to select the appropriate engine/transom/ drive
package (including the correct gear ratio and propeller) for a
given boat. Mercury MerCruiser recommends that any new or unique
hull/power package combination be thoroughly water tested prior to
sale, to verify that the boat performs as desired, and that the
engine operates in the appropriate RPM range. It is recommended
that a Mercury MerCruiser Product Application Engineer (PAE) be
contacted for assistance. For assistance outside the United States,
contact the local Mercury Marine office or authorized distributor.
All information, illustrations and specifications contained in this
manual are based on the latest product information available at
time of publication. Mercury Marine reserves the right to make
changes at any time without obligation. As required, revisions to
this manual will be sent to all OEM boat companies.
Page ii
Manual Outline1 - Important Information 2 - Boat Construction 3
- Exhaust System 4 - Fuel System 5 - Cooling System 6 - Drive
System and Engine Installation 7 - Electrical System 8 - Remote
Controls 9 - Predelivery Preparation and Storage
Important Information
Boat Construction
Exhaust System
Fuel System
Cooling System
Drive System and Engine Installation
Electrical System
Remote Controls
Predelivery Preparation and Storage
1 2 3 4 5 6 7 8 9
Page iii
Page iv
SECTION - 1
IMPORTANT INFORMATION
SECTION 1 - IMPORTANT INFORMATIONTable of ContentsTorque
Specifications..............................................................................................................................................
2 Quicksilver
Products................................................................................................................................................
2 Accessories
......................................................................................................................................................
2 Remote Controls and Instrumentation for the DTS
System....................................................................................
3
Identification............................................................................................................................................................
3 Serial Number Decal
Placement.......................................................................................................................3
Bravo Sterndrive Serial Number and
Identification...........................................................................................3
Bravo Transom Serial
Number..........................................................................................................................4
Bravo Three Notice: Trimin Limit
Insert..................................................................................................................
5 Multiple Sterndrive Steering Tie Bar
Arrangements................................................................................................
5 Internal Power Steering With Internal Tie Bar Only
.........................................................................................
6 Internal Power Steering With Internal and External Tie Bar
.............................................................................
6 External Power Steering
..................................................................................................................................
6 External Power Steering With Low External Tie Bar
........................................................................................
6 SeaCore Components and
Castings.......................................................................................................................
6 Stainless Steel
Fasteners........................................................................................................................................
6 Corrosion
Protection................................................................................................................................................
7 Antifouling
Paint.....................................................................................................................................................
7 Emission Control Information
Label........................................................................................................................
9 Owner Responsibility
......................................................................................................................................
10 Star
Label..............................................................................................................................................................
10 Hang
Tag...............................................................................................................................................................
11
1
90-899883178 NOVEMBER 2007
Page 1 / 12
IMPORTANT INFORMATION
SECTION - 1
Lubricants, Sealants, AdhesivesTube Ref No.34
Description Special Lubricant 101
Where Used Threads of stainless steel fasteners
Part No. 92-802865Q02
Torque SpecificationsNOTE: Securely tighten all fasteners not
listed below. NOTE: The propeller torque stated is a minimum torque
value.Description Exhaust tube clamp Exhaust pipe bolts Exhaust
blockoff plate bolts Bravo One propeller nut Bravo Two propeller
nut Bravo Three front propeller nut Bravo Three rear propeller nut
Rear engine mounting bolts Steering cable coupler nut Steering
system pivot bolts Sterndrive unit fasteners Transom assembly
fasteners Mounting clip screw Hose clamps Water inlet fitting bolts
Water inlet blockoff screw Fuel inlet fitting Gen III Cool Fuel
Module captured nut Battery stud Propeller shaft anode screw Nm 3
34 34 75 81 136 81 47 47 34 68 34 12.2 2 5 5 lbin. 26 108 26 45 45
lbft 25 25 55 60 100 60 35 35 25 50 25
Then align tabs with grooves Then align tabs with grooves
Finger tight + 13/4 to 21/4 turns with a wrench. Do not
overtighten. 19 811 19 168 7191 168
Quicksilver ProductsAccessoriesQuicksilver gauges, remote
controls, steering systems, propellers, and other accessories are
available for this product. Mercury MerCruiser recommends the use
of Quicksilver parts on all applications. Refer to Mercury
Precision Parts Accessories Guide for a complete listing. This
Guide is available from: Attn: Parts Department Mercury Marine
W6250 W. Pioneer Road P.O. Box 1939 Fond du Lac, WI 54935-1939
Outside of U.S.A., order through Distribution Center or
Distributor.
Page 2 / 12
90-899883178 NOVEMBER 2007
SECTION - 1
IMPORTANT INFORMATION
Remote Controls and Instrumentation for the DTS SystemThe
Digital Throttle and Shift system (DTS) requires the use of
specialized helm components, including a command module kit and
electronic remote control. Refer to the Mercury Precision
Parts/Quicksilver Accessories Guide.
IdentificationSerial Number Decal PlacementThere are 3 sets of
engine, transom assembly, and sterndrive serial number decal strips
provided with each power package. One should be used for each of
the following: Engine Specification Decal Warranty Registration
Card Operation, Maintenance and Warranty Manual identification page
Affix engine serial number decal to specification / serial number
decal.
8331
aa - Specification/serial number decal
Bravo Sterndrive Serial Number and IdentificationThe sterndrive
serial number, gear ratio, model number, and bar code is embedded
in the ground plate located on the port side of the Bravo
sterndrive.
a
b
c d
25906
a - Bar code b - Serial Number
c - Gear ratio d - Model number
90-899883178 NOVEMBER 2007
Page 3 / 12
IMPORTANT INFORMATION
SECTION - 1
The serial number is also stamped on the sterndrive casting
inside the back cover. This is used as a permanent reference for
authorized MerCruiser Dealers.
a
25907
Bravo sterndrive serial number stamping a - Serial number
stamping
Bravo Transom Serial NumberThe Bravo transom serial number is
stamped in the Ubolt plate of the Bravo transom assembly.
a
25904
Bravo transom assembly Ubolt plate a - Transom assembly serial
Number
Page 4 / 12
90-899883178 NOVEMBER 2007
SECTION - 1
IMPORTANT INFORMATION
The serial number is also stamped on the gimbal housing. This is
used as a permanent reference for authorized MerCruiser
Dealers.
a
25905
Gimbal housing with serial number stamping a - Transom assembly
serial Number
Bravo Three Notice: Trimin Limit InsertNOTE: Bravo One, Two and
Three Models are equipped with a trimin limit insert. It has been
brought to our attention that some boats (predominantly deepVee
heavy boats) will roll up on their side under certain, specific,
operating conditions. The roll can be either to port or starboard
and may be experienced while moving straight ahead, or while making
a turn. The roll occurs most frequently at or near maximum speed,
with the sterndrive unit trimmed at or near full trimin. While the
boat will not roll completely over, the roll may be sufficient to
unseat the operator or passengers, and thereby create an unsafe
situation. The roll is caused by sternlift created from excessive
sterndrive unit trimin. Under these extreme sternlift / bowdown
conditions, instability can be created, which may cause the boat to
roll. Weight distribution to the stern can reduce sternlift and, in
some circumstances, help to control the condition. Weight
distribution in the bow, port or starboard, may worsen the
condition. The trimin limit insert reduces sternlift by preventing
the sterndrive unit from reaching the last few degrees of full trim
under. While this device should reduce the rolling tendency, it may
not eliminate the tendency entirely. The need for this trimin limit
insert, and its effectiveness, can only be determined through boat
testing and is ultimately the responsibility of the boat
manufacturer.
! WARNINGOn some boats, increased trimin range can cause
handling problems at high speeds, resulting in personal injury or
death. We recommend that only qualified personnel adjust the trimin
limit inserts and test the boat for handling problems.
Multiple Sterndrive Steering Tie Bar ArrangementsWith multiple
sterndrives you must select one of several possible steering
systems.
NOTICEIncorrect tie bar installation can damage the drive and
steering system. Do not let the tie bar contact other components
during severe turning conditions. Always calculate sufficient
turning clearances, observe recommended tie bar arrangements, and
check for proper installation before operating the boat.
90-899883178 NOVEMBER 2007
Page 5 / 12
IMPORTANT INFORMATION
SECTION - 1
Internal Power Steering With Internal Tie Bar OnlyAt the lower
end of the performance spectrum, boats not capable of speeds in
excess of 97 km/ h. (60 MPH), the basic internal tie bar is
recommended. It connects the slave sterndrive to the sterndrive
that is directly connected to the factory power steering output.
This internal tie bar is available in a variety of lengths from the
sterndrive manufacturer.
Internal Power Steering With Internal and External Tie BarAs a
boat moves into the moderate performance range of 97113 km/h. (6070
MPH) or for a reduction in steering backlash, an external tie bar
should be added. External tie bars are usually designed to attach
at the aft power trim cylinder bosses. This location is an
excellent choice because of its proximity to the propeller.
HOWEVER, because of the potential overstress that can occur if one
sterndrive is trimmed much differently than the other, a dual trim
control kit (Part Number 90362A3) should be installed to limit this
potential tilt differential to about 20 degrees. IMPORTANT: Mercury
Marine does not recommend the use of an external tie bar ONLY with
no internal tie bar when using the internal power steering system.
This can cause excessive loads on the steering components on the
sterndrive connected to the internal power steering system. These
increased loads can damage the steering components, resulting in
increased play in the steering of the boat.
External Power SteeringWhen boat speeds move past 113 km/h (70
MPH) or if additional steering backlash reduction is desired,
external power steering is recommended. This normally will include
an external tie bar mounted at the same general location as the
power steering cylinders, which are generally attached at the top
of the sterndrive's drive shaft housing. With this steering system,
no internal tie bar should be used. These steering cylinders can be
attached either inboard (between) or outboard of the
sterndrives.
External Power Steering With Low External Tie BarFor the fastest
boats, over 129 km/h (80 MPH) , or for the ultimate in steering
backlash reduction, use external power steering, BUT (where
mechanically possible) with the external tie bar mounted at the
trim cylinder boss location (as previously described in "Internal
Power Steering with Internal and External Tie Bar" statements).
Again, this system does not use an internal tie bar.
SeaCore Components and CastingsMercury MerCruiser SeaCore power
packages are equipped with additional stainless steel components
and particular aluminum castings with special coatings. Do not
replace SeaCore components with nonSeaCore. Use only the specified
Mercury MerCruiser SeaCore components and castings on these power
packages.
Stainless Steel FastenersSeaCore models are equipped with
additional stainless steel fasteners to maximize corrosion
resistance in salt water environments. Stainless steel fasteners
are subject to galling when installed without lubrication. Galling
can result in fastener destruction, improper clamp loads, or both.
Galled fasteners may appear to torque properly, but still have
incorrect clamp loads. Apply a lubricant, such as Special Lubricant
101 or an equivalent, on the threads of stainless steel fasteners
during installation to avoid galling. Lubricate at least the first
8 mm (1/4 in.) of the threads before installation.Tube Ref
No.34
Description Special Lubricant 101
Where Used Threads of stainless steel fasteners
Part No. 92-802865Q02
Page 6 / 12
90-899883178 NOVEMBER 2007
SECTION - 1
IMPORTANT INFORMATION
Corrosion ProtectionMercury MerCruiser power packages are
equipped with anodes to help protect them from galvanic corrosion
under moderate conditions. However, for severe conditions or if
using a stainless steel propeller, it is recommended that a
Quicksilver AntiCorrosion Anode Kit and/or a MerCathode System with
2 additional transom mounted anode assemblies be installed (some
models have a MerCathode System as standard equipment). A
MerCathode Monitor also is available to allow the operator to check
the operation of the MerCathode System with the push of a button.
(Refer to Mercury Precision Parts Accessories Guide for part
numbers.) Boats that are connected to AC shore power require
additional protection to prevent destructive low voltage galvanic
currents from passing through the shore power ground wire. A
Quicksilver Galvanic Isolator can be installed to block the passage
of these currents while still providing a path to ground for
dangerous fault (shock) currents. (Refer to Mercury Precision Parts
Accessories Guide for part number.) IMPORTANT: If AC shore power is
not isolated from boat ground, the MerCathode System and anodes may
be unable to handle the increased galvanic corrosion potential.
Antifouling PaintIMPORTANT: Corrosion damage that results from
the improper application of antifouling paint will not be covered
by the limited warranty. Painting Boat Hull or Boat Transom:
Antifouling paint may be applied to boat hull and boat transom but
you must observe the following precautions: IMPORTANT: Do not paint
anodes or pressure wash anodes or MerCathode System reference
electrode and anode, as this will render them ineffective as
galvanic corrosion inhibitors.
90-899883178 NOVEMBER 2007
Page 7 / 12
IMPORTANT INFORMATION
SECTION - 1
IMPORTANT: If antifouling protection is required for boat hull
or boat transom, copper base paint, if not prohibited by law, can
be used. If using copper based antifouling paint, observe the
following: Avoid an electrical interconnection between the Mercury
MerCruiser Product, Anodic Blocks, or MerCathode System and the
paint by allowing a minimum of 40 mm (11/2 in.) UNPAINTED area on
transom of the boat around these items.
a
b8107
a - Painted boat transom
b - Minimum 40 mm (11/2 in.) unpainted area around transom
assembly
NOTE: Sterndrive unit and transom assembly can be painted with a
good quality marine paint or an antifouling paint that DOES NOT
contain copper or any other material that could conduct electrical
current. Do not paint drain holes, anodes, MerCathode system or
items specified by boat manufacturer.
NOTICEWashing the MerCathode assembly can damage components and
lead to rapid corrosion. Do not use any cleaning equipment such as
brushes or highpressure washers to clean the MerCathode
assembly.
Page 8 / 12
90-899883178 NOVEMBER 2007
SECTION - 1
IMPORTANT INFORMATION
Do not wash the sterndrive unit with a power washer as this can
damage the coating on the reference wire of the MerCathode
assembly, if equipped, and increase corrosion.
c
a
ba - MerCathode reference electrode b - Do not paint c - Do not
pressure wash6211
Emission Control Information LabelA tamperresistant Emission
Control Information label is affixed in a visible location to the
engine at time of manufacture by Mercury MerCruiser. In addition to
the required emissions statement, the label lists the engine serial
number, family, STD (emission standard/level), date of manufacture
(month, year), and the engine displacement. Please note that the
low emissions certification will not affect the fit, function, or
performance of the engines. Boatbuilders and dealers may not remove
the label or the part it is affixed to before sale. If
modifications are necessary, contact Mercury MerCruiser about the
availability of replacement decals before proceeding.
NOTE: When the CE mark is present in the lower right corner of
the Emission Control Information Label on the engine, the
Declaration of Conformance applies. Refer to the front page of this
manual for further information.
EMISSION CONTROL INFORMATIONTHIS ENGINE CONFORMS TO XXXX
CALIFORNIA EMISSION REGULATIONS FOR SPARK IGNITION MARINE ENGINES
REFER TO OWNER'S MANUAL FOR MAINTENANCE SPECIFICATIONS AND
ADJUSTMENTS SERIAL # XXXXXXXX FAMILY XXXXXXXXXXXX STD. XX.X g/kW-hr
D.O.M. DISPMMM YYYY
X.XL
0575
Emission Control LabelCalifornia EmissionsCompliant
"SERIAL#"Engine Serial Number "FAMILY"Engine Family "STD."Emissions
Standard "D.O.M."Date of Manufacture
31656
90-899883178 NOVEMBER 2007
Page 9 / 12
IMPORTANT INFORMATION
SECTION - 1
"DISP"Piston Displacement
EMISSION CONTROL INFORMATION
NOT FOR SALE IN CALIFORNIAREFER TO OWNER'S MANUAL FOR
MAINTENANCE SPECIFICATIONS AND ADJUSTMENTS SERIAL # XXXXXXXX FAMILY
XXXXXXXXXXXX STD. XX.X g/kW-hr D.O.M. DISPMMM YYYY
X.XL31657
Emission Control LabelNot for Sale in California "SERIAL#"Engine
Serial Number "FAMILY"Engine Family "STD."Emissions Standard
"D.O.M."Date of Manufacture "DISP"Piston Displacement
Owner ResponsibilityThe operator must have routine engine
maintenance performed to maintain emission levels within prescribed
certification standards. The operator may not modify the engine in
any manner that alters the horsepower or allows emissions levels to
exceed their factory specifications.
Star LabelThe 4.3 models meet the California Air Resources
Board's ThreeStar Sterndrive and Inboard marine engine 2003 exhaust
emission standards. The ThreeStar label will be affixed on the left
side of the hull as shown.
a
XX 1234 XX
b32973
a - Recommended location
b - Secondary location
Page 10 / 12
90-899883178 NOVEMBER 2007
SECTION - 1 One Star - Low emission
IMPORTANT INFORMATION
mc79569-1
The onestar label identifies personal watercraft, outboard,
sterndrive and inboard engines that meet the Air Resources Board's
Personal Watercraft and Outboard marine engine 2001 exhaust
emission standards. Engines meeting these standards have 75% lower
emissions than conventional carbureted twostroke engines. These
engines are equivalent to the U.S. EPA's 2006 standards for marine
engines.
Two Stars - Very Low emission The twostar label identifies
personal watercraft, outboard, sterndrive and inboard engines that
meet the Air Resources Board's Personal Watercraft and Outboard
marine engine 2004 exhaust emission standards. Engines meeting
these standards have 20% lower emissions than One Star LowEmission
engines.
FO
IDA
mc79570-1
Three Stars - Ultra Low emission The threestar label identifies
engines that meet the Air Resources Board's Personal Watercraft and
Outboard marine engine 2008 exhaust emission standards or the
Sterndrive and Inboard marine engine 2003 exhaust emission
standards. Engines meeting these standards have 65% lower emissions
than One Star Low Emission engines.
SS
A
D
mc79571-1
Four Stars - Super Ultra Low emission The Four Star label
identifies engines that meet the Air Resources Board's Sterndrive
and Inboard marine engine 2009 exhaust emission standards. Personal
Watercraft and Outboard marine engines may also comply with these
standards. Engines meeting these standards have 90% lower emissions
than One Star Low Emission engines.
FN R
T
mc79572-1
Hang TagOn 4.3 models, the Dealer must mark the appropriate box
on one hang tag to match the Star label affixed to the boat. The
dealer is responsible for displaying the hang tag in a visible
location on the boat on display in California. Failure to properly
display the hang tag could result in a citation and possible fine
to the dealer from the California Air Resources Board. If in
California, the dealer must place the hang tag in a visible
location in the boat prior to displaying the boat.
90-899883178 NOVEMBER 2007
Page 11 / 12
IMPORTANT INFORMATION
SECTION - 1
NOTES:
Page 12 / 12
90-899883178 NOVEMBER 2007
SECTION - 2
BOAT CONSTRUCTION
SECTION 2 - BOAT CONSTRUCTIONTable of ContentsBoat
Construction....................................................................................................................................................
2 Transom Thickness and Surface
Plane............................................................................................................2
Transom
Cutout.................................................................................................................................................2
Checking Transom
Thickness...........................................................................................................................2
Engine
Bed........................................................................................................................................................2
2
90-899883178 NOVEMBER 2007
Page 1 / 2
BOAT CONSTRUCTION
SECTION - 2
Boat ConstructionTransom Thickness and Surface PlaneIMPORTANT:
Transom thickness and surface plane (flatness) must be controlled
where the sterndrive unit mounts.Transom Specifications Thickness
Between 51 57 mm (2 21/4 in.) for 203 mm (8 in.) to either side of
the vertical center line Parallelism Inner and outer surfaces must
be parallel within 3 mm (1/8 in.) Flatness Angle Transom surfaces
in area where transom assembly will be mounted (includes vertical
as well as horizontal dimensions) :Inner Surface Flat within 3 mm
(1/8 in.) Outer Surface Flat within 2 mm (1/16 in.) 10 16
degrees
a
e d b d
ca - Transom thickness b - Inner surface c - Outer surface
7508
d - Transom plate coverage 203 mm (8 in.) from center e -
Transom angle
Transom CutoutRefer to Section 6 - Drive System And Engine
Mounting.
Checking Transom ThicknessRefer to Section 6 - Drive System And
Engine Mounting.
Engine BedIMPORTANT: The finished boat stringer must position
the front engine mount so that a minimum of 6 mm (1/4 in.) up or
down adjustment exists after the mount is adjusted to contact the
stringer. This allows for future engine alignment or adjustments.
Make proper alterations to the boat stringer (structure) to obtain
the 6 mm (1/4 in.) dimension.Description Difference between
starboard and port engine mount Mount adjustment up and down
(minimum) Specification 57.2 cm (221/2 in.) 6 mm (1/4 in.)
NOTE: Although the engine mounts allow some adjustment, it is a
good practice to ensure that the front and rear mount locations in
the vessel are parallel and in the same plane. This may be checked
by tying a string from the left front mount location to the right
rear mount location and another from right front to left rear. The
strings should touch where they cross.
Page 2 / 2
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
SECTION 3 - EXHAUST SYSTEMTable of ContentsExhaust
System.......................................................................................................................................................
2 Important
Information........................................................................................................................................2
Carbon Monoxide
Poisoning.............................................................................................................................2
Good Ventilation
........................................................................................................................................
2 Poor Ventilation
.........................................................................................................................................
3 Measuring Exhaust Elbow
Height...........................................................................................................................
3 General
Information...........................................................................................................................................3
Exhaust Angle Measurement
.....................................................................................................................
4 Boat
Requirements............................................................................................................................................4
Loading
Requirements......................................................................................................................................5
Loading the Boat with a Capacity
Plate.............................................................................................................5
Example
.....................................................................................................................................................
6 Loading the BoatWithout a Capacity
Plate....................................................................................................7
Example
.....................................................................................................................................................
8 Clear Hose Measurement
Method..................................................................................................................10
Clear Hose Measurement Method from Seacock or Muffler
Drain..................................................................
11
3
90-899883178 NOVEMBER 2007
Page 1 / 12
EXHAUST SYSTEM
SECTION - 3
Exhaust SystemImportant Information
NOTICEImproperly designing, installing, or modifying the engines
exhaust system can introduce seawater or water from condensation
into the combustion chambers, damaging the engine. The installing
dealer or boat builder is responsible for proper installation of
the exhaust system as explained in the installation instructions
for the product. Engine damage resulting from water ingestion is
not covered by the product warranty, unless the damage is the
result of a defective part supplied by the engine manufacturer. The
exhaust system must be installed in accordance with the information
contained in this section to prevent water intrusion problems.
Special care is required on the transom or hull exhaust
applications, as these customdesigned exhaust systems can create a
tuning effect that can cause water to be forced back into the
engine. The instructions under Checking for Water Intrusion must be
performed to ensure that water intrusion is not occurring. It is
the boat manufacturer's responsibility for ensuring that water
intrusion does not exist with their unique exhaust system. Engines
with through propeller exhaust have been carefully designed and
tested to avoid water intrusion problems and no additional testing
is required. These applications require that only that exhaust
elbow height be checked as outlined under Measuring Exhaust Elbow
Height.
! WARNINGInstalling the exhaust system incorrectly can lead to
serious injury or death. When installing or designing exhaust
systems, follow all federal, state, and local boating and safety
standards for the market in which the boat will be sold. Exhaust
system design and installation can affect: Noise level.
Performance. Water Intrusion. Carbon monoxide levels. Component
longevity.
Carbon Monoxide PoisoningIMPORTANT: The following important
information is covered in the owner's operation, maintenance and
warranty manuals. You may also want to include this information in
the boat owner's manual. Carbon monoxide is present in the exhaust
fumes of all internal combustion engines including the outboards,
sterndrives, and inboard engines that propel boats, as well as the
generators that power various boat accessories. Carbon monoxide is
a deadly gas that is odorless, colorless, and tasteless. Early
symptoms of carbon monoxide poisoning, which should not be confused
with seasickness or intoxication, include headache, dizziness,
drowsiness, and nausea.
! WARNINGCarbon monoxide poisoning can lead to unconsciousness,
brain damage, or death. Keep the boat well ventilated while at rest
or underway and avoid prolonged exposure to carbon monoxide.
GOOD VENTILATIONVentilate passenger area, open side curtains, or
forward hatches to remove fumes.
Page 2 / 12
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
1. Example of desired air flow through the boat.
mc79553-1
POOR VENTILATIONUnder certain conditions, permanently enclosed
or canvas enclosed cabins or cockpits with insufficient ventilation
may draw in carbon monoxide. Install 1 or more carbon monoxide
detectors in your boat. Although the occurrence is rare, on a very
calm day, swimmers and passengers in an open area of a stationary
boat that contains or is near an operating engine may be exposed to
a hazardous level of carbon monoxide. 1. Examples of poor
ventilation while a boat is stationary:
aa - Operating the engine when the boat is moored in a confined
space.
b
mc79554-1
b - Mooring close to another boat with its engine operating.
2. Examples of poor ventilation while a boat is moving:
aa - Operating the boat with the trim angle of the bow too
high.
b
mc79556-1
b - Operating the boat with no forward hatches open (station
wagon effect).
Measuring Exhaust Elbow HeightGeneral InformationThe height of
the exhaust elbows must be within the dimensions specified to
prevent water intrusion problems. Exhaust elbow risers must be
installed, if needed, to obtain the proper exhaust elbow height and
exhaust angle. Risers are limited to 152.4 mm (6 in.) on all 4.3
and 5.0 models. Measurement must be taken with the boat in the
water. Load the boat as outlined to simulate the maximum loading
conditions likely to be encountered in normal operation. IMPORTANT:
Exhaust elbow height is measured to the waterline inside of the
water lift muffler (instead of the water line outside of the boat)
on applications so equipped. Refer to Water Lift Muffler.
IMPORTANT: Load distribution recommendations are the responsibility
of the boat manufacturer. Any load distribution conditions that
will affect the exhaust system must be clearly communicated to the
operator in the owner's manual. For example, the number of people
that can be located on the swim platform simultaneously should be
included in the manual if this could pose a problem. Measurements
under all loading conditions must be within the following
specifications.Minimum Exhaust Elbow Height Model 4.3, 5.0 MPI and
SeaCore 4.3, 5.0 Models Specifications 330 mm (13 in.)
90-899883178 NOVEMBER 2007
Page 3 / 12
EXHAUST SYSTEM Minimum Exhaust Hose Slope Model 4.3, 5.0 MPI and
SeaCore 4.3, 5.0 Models
SECTION - 3
Specification within 45.7 cm (18 Specification for the remainder
of in.) of the engine system (if applicable) 10 3
If the exhaust elbow height or exhaust angle is insufficient,
modify the exhaust system or install the appropriate exhaust riser.
Refer to the appropriate Mercury Precision Parts and Accessory
Guide for part numbers. The maximum exhaust riser height is
specified in the table below.Riser Options Model 4.3, 5.0 MPI and
SeaCore 4.3, 5.0 Models Low 76 mm (3 in.) and 43 mm (1.7 in.)
Medium 76 mm (3 in.) and 43 mm (1.7 in.) High 152 mm (6 in.)
EXHAUST ANGLE MEASUREMENTMeasure the exhaust angle of each
section of the exhaust system using an inclinometer as shown in the
diagram below. Begin the measurement at the exhaust elbow outlet
continuing along each section to the exhaust exit point of the
boat. All exhaust angle measurements must be performed with the
boat at rest in the water. Perform the first set of measurements
without a load in the boat. Perform the second set of measurements
with the boat fully loaded. See Loading Requirements.
c a
b18582
Typical Exhaust a - Inclinometer b - Exhaust hose or tube
c - Minimum 305 mm (12 in.)
Boat RequirementsIMPORTANT: Consider the following requirements
before performing the exhaust elbow waterline height measurement.
No prototype hulls or light layup hulls should be considered. Any
measurement performed on nonproduction boats, prototype hulls, or
light layup hulls could be inaccurate and could result in product
damage. All boats that display a CE certification capacity plate
must use the maximum capacity as stated on the CE certification
capacity plate to perform the exhaust elbow waterline measurement.
All boats that only display the US Coast Guard (USCG) capacity
plate must use the maximum capacity as stated on the USCG capacity
plate to perform the exhaust elbow waterline measurement.
Page 4 / 12
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
For boats that do not have a capacity plate, the maximum
capacity load is the number of persons that can sit on designated
seating plus cargo excluding cabin space. Measurements used for
official Mercury MerCruiser audit at the OEM boat builder must be
performed on current production boats. No prototype hulls or light
layup hulls will be considered for official audit purposes.
Measurements used for official Mercury MerCruiser audit at OEM boat
builders must use the CE certification maximum load for any boat
model that will be sold outside of the United States.
Loading Requirements1. Fill the fuel tanks, fresh water tanks or
holding tanks, ballast tanks, and heater tanks to simulate fully
loaded condition. 2. Weights can be used to simulate these load
conditions if desired. Place weights in the corresponding area for
which the load is being replaced. Refer to the following
conversions. 1 U.S. gallon of water = 8.3 lb. 1 liter of water = 1
kg 1 U.S. gallon of gasoline = 6 lb. 1 liter of gasoline = 0.72 kg
3. For the purpose of MerCruiser waterline height measurements: One
person is equivalent to 74.84 kg (165 lb.) Cargo per person is
equivalent to 11.34 kg (25 lb.) 4. Add weight for any additional
boat options: extra battery, battery charger, tower, arch,
generator, ballast tanks, ballast sacks, television, carpet,
anchor, stereo/entertainment equipment, washer/dryer, safe, etc. 5.
If a swim platform is an option, the swim platform must be
installed for the waterline height measurement. Use the following
guide to determine the correct swim platform load: a. Boats less
than 8.84 m (29 ft.) long, not including boats that are 8.84 m (29
ft.) long, must add the maximum rated swim platform weight capacity
to the swim platform. b. Boats less than 8.84 m (29 ft.) long, not
including boats that are 8.84 m (29 ft.) long that do not have a
maximum rated swim platform weight capacity, must add181.45 Kg (400
lb.) to the swim platform . c. Boats 8.84 m (29 ft.) long and
greater than 8.84 m (29 ft.) long, must add the maximum rated swim
platform weight capacity to the swim platform. d. Boats 8.84 m (29
ft.) long and greater than 8.84 m (29 ft.) long, that do not have a
maximum rated swim platform weight capacity must add 226.80 kg (500
lb.) to the swim platform.
Loading the Boat with a Capacity PlateFor boats with a capacity
plate, use the maximum load for persons and gear as listed on the
capacity plate to determine the number of persons to place onto the
boat for exhaust elbow waterline height measurements. IMPORTANT:
Use 20 inches for average passenger seat width when measuring bench
seating. Round up or down at 0.5 to obtain a whole person. See the
examples listed below. 48 in. (bench seat length) 20 in. (seat
width) = 2.4 persons. 2.4 persons rounded down = 2 persons. 55 in.
(bench seat length) 20 in. (seat width) = 2.75 persons. 2.75
persons rounded up = 3 persons. 1. Take the maximum capacity weight
as listed on the capacity plate (XXXX lb. Persons, Gear) and
subtract the swim platform load, if applicable. 2. Next divide the
weight by 74.84 kg (165 lb.) per person. This gives the whole
number and remainder of 74.84 kg (165 lb.) persons to load onto the
boat.
90-899883178 NOVEMBER 2007
Page 5 / 12
EXHAUST SYSTEM
SECTION - 3
3. Put the remainder of a person in the next available seat. See
Boat loading diagram.
24860
24861
CE Capacity Plate
USCG Capacity Plate
IMPORTANT: If there is not enough seating for the number of
people, treat the leftover weight as cargo. Load cargo weight onto
the boat before loading passenger weight. 4. If applicable, load
cargo (leftover persons weight) onto the boat. Distribute cargo as
described below. IMPORTANT: If the boat configuration does not
allow for aft, center, and bow storage, choose the storage
application from the Optional Cargo Distribution table that best
applies to your boat configuration.Preferred Cargo Distribution Aft
storage 25% Center storage 50% Optional Cargo Distribution Aft
storage 25% None 50% None 100% None Center storage 75% 75% None
100% None None Bow storage None 25% 50% None None 100% Bow storage
25%
5. Perform the first measurement with the swim platform loaded
and the person taking the waterline measurement on the boat. 6.
Load the swim platform if equipped. 7. Measure the exhaust elbow
waterline height. IMPORTANT: View all boat seating as rows that are
parallel to the transom of the boat. 8. Load a person weight into a
seat, and measure the exhaust elbow waterline height after each
person weight is loaded onto the boat. Repeat until a person weight
is is loaded into each seat in that row. 9. Continue the process
moving forward toward the bow of the boat to the next row of seats
until a person weight is loaded into each seat.
NOTE: The total weight loaded onto the boat must not exceed the
maximum capacity displayed on the capacity plate. NOTE: The
following example is provided as a reference.
EXAMPLENOTE: This example uses a boat that is less than 8.84 m
(29 ft.) long, not including a boat that is 8.84 m (29 ft.) long
that does not have a maximum rated swim platform weight capacity,
and must add 181.45 Kg (400 lb.) to the swim platform NOTE: Use
0.50 lb. as the break point to round up or down to obtain a whole
pound.
Page 6 / 12
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
1. Maximum load (persons and gear) from capacity plate swim
platform load = remaining weight to be placed in the boat. 1100 lb.
400 lb. = 700 lb. 2. Remaining weight to be placed in the boat
MerCruiser person weight = number of persons to load onto the boat
700 lb. 165 lb. = 4.24 persons 3. Total number of persons number of
whole persons = remaining persons 4.24 persons 4 persons = 0.24
remaining persons 4. Remainder persons MerCruiser person weight =
remainder MerCruiser person weight 0.24 165 lb. = 40 lb. IMPORTANT:
View all boat seating as rows that are parallel to the transom of
the boat. 5. Using the totals in this example, load four 165lb.
persons and one 40lb. person onto boat seating with 400 lb. on the
swim platform. 400 lb. + 165 lb. = 565 lb. 565 lb. + 165 lb. = 730
lb. 730 lb. + 165 lb. = 895 lb. 895 lb. + 165 lb. = 1060 lb. 1060
lb. + 40 lb. = 1100 lb.
d a b c
e
f24862
Boat loading diagram a - Swim platform load b - MerCruiser
person weight (one) c - MerCruiser person weight (two)
d - MerCruiser person weight (three) e - MerCruiser person
weight (four) f - Remainder MerCruiser person weight (five)
Loading the BoatWithout a Capacity PlateFor boats that do not
display a capacity plate, the number of persons to be loaded onto
the boat for measuring purposes is the number of persons that can
sit on designated seating excluding cabin space. An additional
weight of 25 lb. per person is to be added to the boat before
loading passenger weight onto the boat. IMPORTANT: Use 20 inches
for average passenger seat width when measuring bench seating.
Round up or down at 0.5 to obtain a whole person. See the examples
below. 48 in. (bench seat length) 20 in. (seat width) = 2.4
persons. 2.4 persons rounded down = 2 persons. 55 in. (bench seat
length) 20 in. (seat width) = 2.75 persons. 2.75 persons rounded up
= 3 persons. 1. Total number of persons that can sit on designated
seating excluding cabin space MerCruiser person weight = maximum
passenger load for measurement.
90-899883178 NOVEMBER 2007
Page 7 / 12
EXHAUST SYSTEM
SECTION - 3
Number of persons 165 lb. (MerCruiser person weight) = XXXX lb.
maximum passenger load. 2. Maximum passenger load from the
calculation above swim platform load if applicable. 3. Divide the
weight by 165 lb. per person. This gives the number of 165lb.
persons to load onto the boat. Round up to next whole number. See
Example 3. IMPORTANT: To account for cargo, add a weight of 25 lb.
per person to the boat before loading passenger weight onto the
boat. 4. Calculate the cargo by multiplying 25 lb. by the number of
persons that can sit on designated seating excluding cabin space.
See Example. 5. Load the cargo onto the boat. Distribute cargo as
described below. IMPORTANT: If the boat configuration does not
allow for aft, center, and bow storage, choose the storage
application from the Optional Cargo Distribution table that best
applies to your boat configuration.Preferred Cargo Distribution Aft
storage 25% Center storage 50% Optional Cargo Distribution Aft
storage 25% None 50% None 100% None Center storage 75% 75% None
100% None None Bow storage None 25% 50% None None 100% Bow storage
25%
6. Perform the first measurement with the swim platform loaded
and the person measuring the waterline on the boat. 7. Load the
swim platform if equipped. 8. Measure the exhaust elbow waterline
height. IMPORTANT: View all boat seating as rows that are parallel
to the transom of the boat. 9. Load a person weight into a seat,
and measure the exhaust elbow waterline height after each person
weight is loaded onto the boat. Repeat until a person weight is is
loaded into each seat in that row. 10. Continue the process moving
forward toward the bow of the boat to the next row of seats until a
person weight is loaded into each seat.
EXAMPLENOTE: The following example is provided as a reference.
This example uses a boat that is 8.84 m (29 ft.) long and greater
than 8.84 m (29 ft.) long, that does not have a maximum rated swim
platform weight capacity, and must add 226.80 Kg (500 lb.) to the
swim platform .
Page 8 / 12
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
IMPORTANT: The Designated Seating Diagram following illustrates
the number of passengers that can sit on designated seating
excluding cabin space.
6 9 2 1 3 4 5 7 824863
Designated Seating Diagram This example uses 9 persons as the
maximum passenger load.
NOTE: Use 0.50 lb. as the break point to round up or down to
obtain a whole pound. 1. To determine the maximum cargo load
multiply the maximum passenger load by the maximum cargo weight per
passenger. 9 passengers 25 lb. = 225 lb. 2. To determine the
preferred cargo distribution for aft, center, and bow storage: a.
To determine the maximum aft storage cargo weight, multiply the
maximum cargo weight by 25% 3. To determine the maximum center
storage cargo weight, multiply the maximum cargo weight by 50% a.
225 lb. 50% = 112.50 lb. b. 112.50 lb. rounded up = 113 lb. 4. To
determine the maximum bow storage cargo weight, multiply the
maximum cargo weight by 25% 225 lb. 25% = 56.25 lb. 56.25 lb.
rounded down = 56 lb. 5. To determine the maximum number of
passengers to load onto the boat, multiply 9 passengers by 165 lb.
(MerCruiser person weight) to get a 1485 lb. (total passenger load)
9 passengers 165 lb. = 1485 lb. 6. Subtract the swim platform load
from the total passenger load to get the remaining weight to be
placed in the boat. 1485 lb. 500 lb. = 985 lb. 7. Divide the
remaining weight to be placed onto the boat by the MerCruiser
person weight to get the maximum number of passengers to load onto
the boat. 985 lb. 165 lb. = 5.9 passengers 5.90 passengers rounded
up = 6 passengers 8. Using the totals in this example load 56 lb.
cargo in the aft storage, 113 lb. cargo in the center storage, and
56 lb. cargo in the bow storage onto the boat before adding
passenger weight. Then, load six 165 lb. passengers, onto the boat
with 500 lb. on the swim platform. 500 lb. + 225 lb. = 725 lb. 725
lb. + 165 lb. = 890 lb. 890 lb. + 165 lb. = 1055 lb. 1055 lb. + 165
lb. = 1220 lb. 1220 lb. + 165 lb. = 1385 lb. 1385 lb. + 165 lb. =
1550 lb.
90-899883178 NOVEMBER 2007
Page 9 / 12
EXHAUST SYSTEM
SECTION - 3
1550 lb. + 165 lb. = 1715 lb.
g a c b d h e f24864
i
j
Cargo, swim platform, and passenger weight loading diagram a -
Swim platform load f - MerCruiser person weight (five) b -
MerCruiser person weight (one) g - MerCruiser person weight (six) c
- MerCruiser person weight (two) h - Aft storage d - MerCruiser
person weight (three) i - Center storage e - MerCruiser person
weight (four) j - Bow storage
Clear Hose Measurement Method1. Obtain an 810 mm (5/163/8 in.)
ID (inner diameter) clear hose approximately 4.5 m (15 ft.) long.
Install a metal fitting or a weight on one end of the hose to keep
that end of the hose below the waterline. The fitting or weight
must not restrict water from filling the clear hose.
b b a c
24865
a - Clear hose b - Fitting
c - Unrestricted opening
IMPORTANT: On engines equipped with more than one exhaust elbow,
perform the exhaust elbow waterline height measurement on the side
that sits lower in the water. 2. Put the weighted end of the clear
hose over the side of the boat (port or starboard) that is sitting
lower in the water. 3. Submerge the clear hose until completely
filled with water. 4. Place a finger over the open end of the clear
hose before removing it from the water. 5. Coil the excess clear
hose into the bottom of the boat bilge. Keep the coil of clear hose
below the waterline. 6. Keeping the clear hose in line with the
engine's exhaust elbow, lift the end of the clear hose up to the
highest point of the exhaust elbow.
Page 10 / 12
90-899883178 NOVEMBER 2007
SECTION - 3
EXHAUST SYSTEM
7. Slowly take the finger off of the end of the clear hose to
let the water level stabilize. The water will seek the level of the
water outside of the boat. Keep the clear hose close to the exhaust
elbow and as vertical as possible.
b
c a d8340
e
9142
a - Waterline b - Top of exhaust elbow c - Clear hose
d - Weight e - Measurement, waterline to top of exhaust
elbow
Clear Hose Measurement Method from Seacock or Muffler
DrainIMPORTANT: Measure the exhaust elbow height to the waterline
inside of the water lift muffler (instead of the water line outside
of the boat) on applications so equipped. IMPORTANT: The engine
must have been operated previously to fill the muffler with water.
IMPORTANT: On engines equipped with more than one exhaust elbow,
perform the exhaust elbow waterline height measurement on the side
that sits lower in the water. 1. Attach a clear hose to the muffler
drain point or seacock drain point. 2. Start the engine to fill the
muffler and hose. 3. If attached to the seacock drain, open the
seacock. 4. Route the remainder of the hose toward the engine's
exhaust manifold and elbow. Ensure that this open end section of
the hose is as vertical as possible from the boat's bilge to the
top of the exhaust elbow. 5. Coil excess hose in the bilge of the
boat, keeping it below the water line. 6. Lower the open end of the
hose and siphon water until it starts to come out of the hose. Put
a finger over the hose and lift open end until it is at the top of
the exhaust elbow. 7. Slowly take the finger off of the end of the
hose to let the water level stabilize. The water will seek the
level of the water outside the boat. Keep the hose close to the
exhaust elbow and as vertical as possible.
90-899883178 NOVEMBER 2007
Page 11 / 12
EXHAUST SYSTEM
SECTION - 3
8. The measurement between the water in the hose and the top of
the exhaust elbow is the exhaust elbow height. The maximum riser
height is 15.2 cm (6 in.).
a
b24866
Typical vertical water lift muffler a - Minimum exhaust elbow
height with b - Clear hose for measuring waterline maximum load
a
b
24867
Typical horizontal water lift muffler a - Minimum exhaust elbow
height with b - Clear hose for measuring waterline maximum load
Page 12 / 12
90-899883178 NOVEMBER 2007
SECTION - 4
FUEL SYSTEM
SECTION 4 - FUEL SYSTEMTable of ContentsFuel Delivery System
..............................................................................................................................................
2 California Regulations for 2007LowPermeation Fuel
Hose..........................................................................2
Fuel Lines and
Fittings......................................................................................................................................2
Fuel Delivery System
.......................................................................................................................................3
Special Information About Electric Fuel Pumps
.........................................................................................
4
4
90-899883178 NOVEMBER 2007
Page 1 / 4
FUEL SYSTEM
SECTION - 4
Fuel Delivery SystemCalifornia Regulations for 2007LowPermeation
Fuel HoseCalifornia Regulations for New 2007 and Later
Spark-Ignition Inboard/Sterndrive Pleasurecraft (3) Requirements of
engine manufacturers and boat manufacturers under Option 2 and
using Low Permeation Fuel Line Hose: (A) Each manufacturer that
chooses Option 2 must provide written instructions, as part of the
installation materials provided to purchasers of the engine, to use
Low Permeation fuel Line Hose for the primary Fuel line connecting
the fuel tank to the engine of any boat that is manufactured for
sale, sold, or offered for sale in California, or that is
introduced, delivered or imported into California for introduction
into commerce. (B) Each boat manufactured must install Low
Permeation Fuel Line Hose for the primary Fuel line connecting the
fuel tank to the engine of any boat that is manufactured for sale,
sold, or offered for sale in California that uses an engine from a
manufacturer that chooses Option 2. Low Permeation Fuel Line Hose
is USCG Type A115, defined as not exceeding 15 g/m/24 h with CE10
fuel at 23 C as specified in SAE J 1527Marine Fuel Hoses.
Fuel Lines and FittingsWe recommended that you measure the exact
route and length of the fuel lines before the first installation of
the engine to prevent problems later in connecting them to the
engine. Only a few points related to function and safety are listed
here. Refer to boating standards (NMMA, ABYC, etc.) and Coast Guard
regulations for complete guidelines. Use fuel lines that are Coast
Guard approved USCG Type A1. The U.S. boating standards and
regulations specify the sole use of USCG Type A1 fuel lines in the
engine compartment or in any location in the boat where a break in
the line could result in a discharge of 150 cc (5 oz.) of fuel in 2
minutes. Ensure that the fuel pickup is at least 25 mm (1 in.) from
the bottom of fuel tank to prevent picking up impurities. Using a
digital vacuum gauge, measure the vacuum at the engine's fuel
inlet. The maximum measured vacuum at the engine's fuel inlet must
not exceed 6.9 kPa (2 in. Hg) throughout engine operating range.
IMPORTANT: Vacuum reading higher than specified can cause vapor
locking with some of today's fuels. It can also cause poor engine
performance because of fuel starvation. Follow the minimum fuel
line diameter specification listed below.Description Minimum fuel
line diameter on singleengine gasoline installations Minimum fuel
line diameter on multiengine gasoline installations with single
pickup and line Specification 10 mm (3/8 in.) 13 mm ( in.) ID or
larger
On multi-engine gasoline installations, use a fuel pickup and
fuel tank supply line for each engine. If a single pickup and line
is used, the line must be 13 mm ( in.) ID or larger. On
installations that require long lines or numerous fittings, use the
fuel lines and fittings with an ID greater than 10 mm (3/8 in.).
Use the Engine Compartment/Fuel System Pressure and Temperature
Test to determine if the fuel pressure and temperature are within
an acceptable range. If the temperature is excessive, reduce the
fuel line length, reduce the number of fittings or insulate the
components. Refer to the Engine Compartment/Fuel System Pressure
and Temperature Test in the Mercury MerCruiser Product Applications
Manual. Route the fuel lines as low as possible in the engine
compartment to keep them in the coolest region. Temperature
increases significantly with increased engine compartment
height.
Page 2 / 4
90-899883178 NOVEMBER 2007
SECTION - 4
FUEL SYSTEM
Route the slope of the fuel line as consistent as possible to
avoid high spots that can trap vapor and contribute to vapor
locking problems. Ensure that the holes where the fuel lines run
through the bulkheads are carefully rounded off or protected with
grommets to prevent damage from vibration and chafing. Keep the
fuel line free of stress and firmly secured to prevent vibration
and chafing. Secure the fuel line with clamps that will not pinch
or kink the line. Do not route the fuel line with sharp bends. Use
a flexible fuel line to connect the fuel supply line to the fuel
inlet fitting on the engine. The flexable line will absorb
deflection between the engine and the hull structure when the
engine is running. Keep all the fuel lines well secured. IMPORTANT:
If the engine is equipped with a boost pump, an inline filter must
be installed between the fuel tank and the boost pump. This filter
is provided with the engine package. The 100 Vazer model is
equipped with a fuel prefilter already installed on the engine. Do
not install a inline fuel filter on Vazer models. The fuel delivery
system must be designed to deliver the fuel to the engine with
minimal restriction and at the lowest temperature. Gasoline is
extremely sensitive to vaporizing if placed under a vacuum (low
pressure) and exposed to moderate or high temperatures. This is
particularly true if winter blend fuels with a high RVP (Reid Vapor
Pressure) are encountered in warmer temperature areas. Excessive
restriction in the fuel delivery system may cause a condition known
as vapor locking. This typically occurs after the engine has been
operated at high RPM and then shut off and allowed to sit for 15
minutes to 2 hours. During this time the engine heat soaks, causing
the temperature of the fuel system to increase. Upon restart, the
combination of heat and vacuum in the fuel system causes the fuel
to vaporize. The fuel system cannot handle this vapor and
therefore, fuel starvation results when the boater attempts to
resume operation. Depending upon the degree of vapor locking, this
can range from a hesitation or bog when accelerating to a complete
stalling of the engine. To minimize the potential for this problem,
the guidelines should be observed to limit fuel delivery
restriction to 6.9 kPa (2 in. Hg) or less and fuel inlet
temperature to 44 C (110 F) or less. The fuel delivery system is an
integral part of the boat. Mercury MerCruiser makes no attempt in
this manual to cover all aspects of design and integration of the
fuel delivery system, due to a broad range of possible
configurations and the numerous regulations and standards that
cover this area. The applicable standards and regulations for the
markets where your product will be sold should be observed, along
with any information from the fuel system component manufacturers.
The following general guidelines are provided:
! WARNINGImproper boat design and construction may result in
serious injury or death. Adhere to all applicable marine
regulations (United States Coast Guard [USCG], European Union
Recreational Craft Directive [EURCD], etc.) and the standards they
reference (American Boat and Yacht Council [ABYC], Society of
Automotive Engineers [SAE], International Standards Organization
[ISO], etc.) when designing and constructing the boat and other
components, such as the engine compartment, fuel delivery system,
or exhaust system. The main concern of a boat's fuel system is
safety; this must be achieved through a technically sound
installation and constant inspection. The fuel system, from the
filler pipe to the fuel pump, is the same in principle for all
boats. The fuel tank is an integrated component of the boat. Refer
to the special information on service and maintenance, which you
have received from the tank manufacturer. Only a few points related
to function and safety are listed here [Refer to boating standards
(NMMA, ABYC, etc.) and Coast Guard regulations for complete
guidelines]: All connections should be on the upper side of the
tank.
90-899883178 NOVEMBER 2007
Page 3 / 4
FUEL SYSTEM
SECTION - 4
The drain plug at the lowest point on the tank serves to permit
the removal of water and sediment. The tank breather pipe must have
an inner diameter of at least 13 mm (1/2 in.) and must be fitted
with a swan neck to prevent water from entering the tank. It is
recommended that the exact route and length of the fuel lines be
established at the first installation of the engine to prevent
problems later in connecting them to the engine. All fuel lines
must be well secured. The holes where the lines run through the
bulkheads should be carefully rounded off or protected with rubber
grommets. This prevents damage to the lines from abrasion. The
following, but not limited to the following, additional fuel
connection related points, applying to all engines unless otherwise
stated, must be considered [Refer to boating standards (NMMA, ABYC,
etc.) and Coast Guard regulations for complete guidelines]: 1. Fuel
pickup should be at least 25 mm (1 in.) from the bottom of fuel
tank to prevent picking up impurities. 2. Using a digital vacuum
gauge, measure the vacuum at the engine's fuel inlet. The maximum
measured vacuum at the engine's fuel inlet must not exceed 6.9 kPa
(2 in. Hg) through out engine operating range. IMPORTANT: Vacuum
reading higher than specified can cause vapor locking with some of
today's fuels. It can also cause poor engine performance because of
fuel starvation. 3. Use fuel lines that are Coast Guard approved
(USCG Type A1).Description Minimum fuel line diameter on
singleengine gasoline installations Minimum fuel line diameter on
multiengine gasoline installations with single pickup and line
Specification 10 mm (3/8 in.) 13 mm ( in.) ID or larger
4. On multi-engine gasoline installations, use a fuel pickup and
fuel tank supply line for each engine. If a single pickup and line
is used, the line must be 13 mm ( in.) ID or larger. 5. On
installations that require long lines or numerous fittings, use the
fuel lines and fittings with an ID greater than 10 mm (3/8 in.). 6.
Install the fuel lines so they are free of stress and firmly
secured to prevent vibration and/or chafing. 7. Avoided sharp bends
in the fuel lines. 8. Use a flexible fuel line to the fuel inlet
fitting on the engine to absorb deflection when engine is
running.
SPECIAL INFORMATION ABOUT ELECTRIC FUEL PUMPS
! WARNINGImproper boat design and construction may result in
serious injury or death. Adhere to all applicable marine
regulations (United States Coast Guard [USCG], European Union
Recreational Craft Directive [EURCD], etc.) and the standards they
reference (American Boat and Yacht Council [ABYC], Society of
Automotive Engineers [SAE], International Standards Organization
[ISO], etc.) when designing and constructing the boat and other
components, such as the engine compartment, fuel delivery system,
or exhaust system. The installation of additional filters may
cause: Fuel vapor locking. Difficult warmstarting. Piston
detonation due to lean fuel mixture. Poor driveability.
Page 4 / 4
90-899883178 NOVEMBER 2007
SECTION - 5
COOLING SYSTEM
SECTION 5 - COOLING SYSTEMTable of ContentsGeneral
Information.................................................................................................................................................
2 Seawater Supply
System........................................................................................................................................
2 Seawater Supply
Hose......................................................................................................................................2
Seawater Inlet
Hose..........................................................................................................................................2
ThroughHull Seawater Pickup
System.............................................................................................................
3 Seawater
Pickup...............................................................................................................................................4
Seacock.............................................................................................................................................................5
Sea
Strainer......................................................................................................................................................6
Sterndrives With Closed Cooling
Engines...............................................................................................................
7 Bravo Models with Closed
Cooling....................................................................................................................
7 SeaCore
Models................................................................................................................................................7
SeaCore Bravo One and Bravo Three Models
..........................................................................................
7 SeaCore Bravo Two Models
......................................................................................................................
7 Seawater Pickups for SeaCore Sterndrive Engine Models
.......................................................................
8 Installing the
YFitting........................................................................................................................................9
Installing the Seawater Supply
Hose.................................................................................................................9
Closed
Cooling......................................................................................................................................................
10
Description......................................................................................................................................................10
Antifreeze
Recommendations.........................................................................................................................10
Coolant Recovery
System...............................................................................................................................11
Hot Water Heater Hose Connections MPI Models
.............................................................................................
11 Supply Hose Connection
................................................................................................................................
12 Return Hose Connection
................................................................................................................................
13 Water Flow
Diagrams............................................................................................................................................
14 V6 and
V8.....................................................................................................................................................14
V8 Bravo Models With Closed Cooling and Risers
................................................................................
14 V6 Alpha Models With Closed Cooling and Risers
.................................................................................
15 V8 Bravo Models With Closed Cooling
...................................................................................................
16 V6 Sterndrive Models With Closed Cooling
............................................................................................
17 V6 Bravo MPD Models With Seawater Cooling
......................................................................................
18 V8 Bravo MPD Models With Seawater Cooling
......................................................................................
19 V8 Bravo Models With Seawater Cooling (Except MPD Models)
........................................................... 20 V6
Bravo Models With Seawater Cooling (Except MPD Models)
........................................................... 21 V6
and V8 Alpha MPD Models With Seawater Cooling
........................................................................
22 V6 and V8 Alpha Models With Seawater Cooling (Except MPD Models)
............................................. 23
5
90-899883178 NOVEMBER 2007
Page 1 / 24
COOLING SYSTEM
SECTION - 5
Lubricant, Sealant, AdhesivesTube Ref No.9 116
Description Loctite 567 PST Pipe Sealant RTV 587 Ultra Blue
Silicone Sealer
Where Used
Part No.
Hose fitting threads and plastic plug threads 92-809822 Sealing
surfaces and screw shaft 92-809825
General InformationMercury MerCruiser engines have either a
seawater cooling system or a closed cooling system. Seawater
cooling systems are sometimes called raw water cooling or standard
cooling, while closed cooling systems are sometimes called fresh
water cooling. On engines with seawater cooling, the engine is
cooled entirely by the seawater in which the boat is being
operated. Closed cooling systems use a combination of fresh water
(antifreeze and water) and seawater for cooling. Both types of
systems are designed to keep the engine operating temperature at
approximately 71 degrees C (160 degrees F) for optimum performance,
fuel economy and durability. (Refer to cooling system flow diagrams
at end of section.) To monitor the cooling system, a temperature
switch is incorporated into the audio warning system, which alerts
the operator of an abnormal condition if the temperature exceeds
approximately 93 degrees C (200 degrees F). A temperature sender is
also employed to operate a temperature gauge at the dash. On dual
helm applications, this sender must be replaced with a dual station
sender to obtain the proper temperature reading at both stations.
Refer to the Instrumentation and Controls section for more
information. The cooling system must receive a sufficient amount of
seawater under all operating conditions to operate properly. The
design and installation of the seawater supply system is the boat
manufacturer's responsibility. Cooling system components must be
constructed, sized, and installed in accordance with the following
guidelines.
NOTICEWithout sufficient cooling water, the engine, the water
pump, and other components will overheat and suffer damage. Provide
a sufficient supply of water to the water inlets during
operation.
Seawater Supply SystemSeawater Supply HoseSeawater Supply Hose
Specifications Seawater inlet hose Seawater pickup Seacock (ABYC
requirement) Sea strainer (optional) Low restriction with 32 mm
(11/4 in.) connections 32 mm (11/4 in.) I.D. (wire reinforced)
Seawater Inlet Hose A reinforced hose capable of supporting 10
in. Hg vacuum must be used to prevent the seawater inlet hose from
collapsing from pump suction. The hose should be oil and seawater
resistant. Use the shortest hose length possible with the least
number of bends to minimize restriction. All connections must be
secured with a hose clamp.
Page 2 / 24
90-899883178 NOVEMBER 2007
SECTION - 5
COOLING SYSTEM
Fasten hose as appropriate to maintain proper routing and to
prevent chafing or contact with other moving parts.
a
a
7638
9361
Typical composite seawater pickup pump a - Seawater inlet hose
connection
Typical brass seawater pickup pump
ThroughHull Seawater Pickup SystemIMPORTANT: Seawater hose used
must be wire reinforced to avoid collapsing hose when suction is
created by seawater pump impeller.
g
c f b e b d a7924
b
Typical installation shown with a through the hull seawater
pickup a - Quicksilver seawater pickup and e - Seawater hose to
engine seacock f - Seawater pump hose connector (if b - Hose clamp
equipped) c - Seawater hose to seawater strainer g - Below seawater
pump level d - Quicksilver seawater strainer IMPORTANT: Do not
install the seawater pickup directly in line with the propeller, as
the pickup may create turbulence and allow air to flow into the
propeller slipstream. This will cause propeller ventilation and
will adversely affect boat performance. IMPORTANT: Make gradual
bends in the seawater hoses to avoid kinks. Hoses must not come in
contact with steering system components, engine coupler, or drive
shaft.
90-899883178 NOVEMBER 2007
Page 3 / 24
COOLING SYSTEM
SECTION - 5
The seawater pickup must be large enough to permit sufficient
seawater flow to engine seawater pickup pump for adequate engine
cooling. The seawater pickup also must supply a positive head while
underway. The seawater pickup should be located as close to the
seawater pump inlet as possible and in an area where an
uninterrupted, solid stream of seawater will flow past when the
boat is underway.
Seawater PickupEither a throughtransom or throughhull seawater
pickup can be used. Select pickup location to minimize seawater
inlet hose length while providing an optimum location for seawater
pickup. The location should be in an area that will provide a
solid, airfree flow of seawater under all operating conditions.
Avoid areas with a disturbed seawater flow, such as those behind or
in close proximity to the propeller. Locations that are too far
forward or outboard should also be avoided as these are prone to
aeration problems at high boat trim angles and in turns. Check for
aeration as outlined under Seawater Supply Test. IMPORTANT: Do not
install the seawater pickup directly in line with the propeller, as
pickup may create turbulence and allow air to flow into the
propeller slipstream. This will cause propeller ventilation and
will adversely affect boat performance. Openings in seawater pickup
should be approximately 3 mm (1/8 in.) maximum to prevent larger
debris from entering and clogging the cooling system. IMPORTANT:
Use a seawater strainer if the seawater pickup openings exceed 3 mm
(1/8 in.). Provisions should be made to minimize galvanic
corrosion, given the hull material being used and the composition
of the surrounding components. Some industry standards and
regulations also require that the pickup be connected into the
boat's bonding system to minimize stray current corrosion. Refer to
applicable standards and regulations for more details. IMPORTANT:
External seawater pickup must have an integral seacock.
7532
Typical seacock
Page 4 / 24
90-899883178 NOVEMBER 2007
SECTION - 5
COOLING SYSTEM
b a g c
d
e
f
h i jTypical transom pickup abcdeHose fitting Nut (4) Gasket
Oring (4) Washer (4)Description Loctite 567 PST Pipe Sealant
Description RTV 587 Ultra Blue Silicone Sealer7558
fghij-
Screw (4) Plastic plug Pickup Screen Screw (2)Part No. 92-809822
Part No. 92-809825
Tube Ref No.9
Where Used Hose fitting threads and plastic plug threads Where
Used Sealing surfaces and screw shaft
Tube Ref No.116
SeacockThe ABYC and other industry standards and regulations
require the use of a seacock on certain types of applications to
stop the entry of seawater in the event of a leak in the cooling
system. Refer to applicable standards and regulations for specific
requirements. The seacock also allows the seawater to be shut off
when servicing the engine.
90-899883178 NOVEMBER 2007
Page 5 / 24
COOLING SYSTEM
SECTION - 5
The seacock must provide minimum restriction to seawater flow
(see Specifications). A ball valve or gate valve is recommended.
The ball valve is most common and is typically equipped with a
lever type handle that operates in a 90 degree arc. This design
gives a clear indication of whether the valve is open or shut.
Industry standards and requirements typically require that the
seacock be rigidly attached to the hull at the seawater pickup.
Seacock location should be readily accessible for quick, easy
operation.
7532
Typical seacock
Sea StrainerA sea strainer is recommended if the boat is to be
operated in an area with a high debris content. The strainer must
be sized to minimize restriction (See Specifications) and to
provide a reasonable service interval. Locate the strainer in an
area that will be easily accessible for servicing. If the boat is
not equipped with a seacock, the strainer should be located above
the seawaterline to prevent seawater entry into boat when
servicing. The strainer must have provision to allow draining in
freezing temperature periods.
7533
Typical Sea Strainer
Page 6 / 24
90-899883178 NOVEMBER 2007
SECTION - 5
COOLING SYSTEM
Sterndrives With Closed Cooling EnginesBravo Models with Closed
CoolingNOTE: Closed cooled Bravo models require a through the hull
or through the transom pickup in addition to the sterndrive water
inlets in order to meet the minimum flow specifications. When
additional water inlets are used, a Yfitting is installed to the
engine seawater pump.
a
c b d8485
Dual seawater pickup for Bravo closed cooled engines a - Engine
seawater pump c - Y fitting port to Bravo drive b - Hose from
seawater pump inlet port d - Yfitting port to additional water
inlet to Yfitting Models operated above the fiftieth parallel of
the northern hemisphere or below the fiftieth parallel of the
southern hemisphere do not require the dual seawater pickup with a
bravo sterndrive on closed cooling models. Remove the Yfitting at
the seawater pump inlet. Install a seawater suppy hose that meets
MerCuiser specifications. Cut the hose to fit from the transom
inlet fitting to the seawater pump inlet.
SeaCore ModelsSome SeaCore models do not require a
throughthehull or throughthetransom seawater pickup to meet the
minimum flow specifications. See the chart, Seawater Pickups for
SeaCore Sterndrive Engine Models.
SEACORE BRAVO ONE AND BRAVO THREE MODELSThe SeaCore Bravo One
and Bravo Three engine packages do not require a throughthehull or
throughthetransom seawater pickup in addition to the sterndrive
water pickups if: The sterndrive gearcase has dual water pickups.
The boat is capable of 64 km/h (40 MPH) with the boat fully loaded
and operated within the specified operating range.
NOTE: When not installing the throughthehull or
throughthetransom seawater pickup, see Installing the Seawater
Supply Hose.
SEACORE BRAVO TWO MODELSThe SeaCore Bravo Two engine packages
must have a throughthehull or throughthetransom seawater pickup in
addition to the sterndrive side water pickups. Install the Yfitting
at the engine's seawater pump inlet. See Installing the
Y-Fitting.
90-899883178 NOVEMBER 2007
Page 7 / 24
COOLING SYSTEM
SECTION - 5
SEAWATER PICKUPS FOR SEACORE STERNDRIVE ENGINE MODELSSeawater
Pickups for SeaCore Sterndrive Engine Models Boat speed with the
boat fully loaded and operated within the specified operating range
SeaCore Bravo has side water pickup SeaCore Bravo has dual water
pickup Throughthehull or throughthetransom seawater pickup
64 km/h (40 MPH) or greater
Not required See Installing the Seawater Supply Hose30180
Less than 64 km/h (40 MPH)3018130180
Required See Installing the Y-Fitting
64 km/h (40 MPH) or greater
Required See Installing the Y-Fitting30181
Greater or Less than 64 km/h (40 MPH) Models operated above the
fiftieth parallel of the northern hemisphere or below the fiftieth
parallel of the southern hemisphere.
Not required See Installing the Seawater Supply
Hose3018130180
Page 8 / 24
90-899883178 NOVEMBER 2007
SECTION - 5
COOLING SYSTEM
Installing the YFittingEngine models that require a
throughthehull or throughthetransom seawater pickup, require a
Yfitting at the engine seawater pump inlet port. The Yfitting
directs the seawater from the sterndrive and throughthehull or
throughthetransom seawater pickup to the engine's seawater pump to
meet the minimum flow specifications.
a
c b dabcd8485
Typical Yfitting installation Engine seawater pump Hose 101.6 mm
(4 in.) from seawater pump inlet to Yfitting port Yfitting port to
water inlet at transom Yfitting port to throughthehull or
throughthetransom seawater pickup
NOTE: For models not factory equipped with a Yfitting, refer to
Mercury Parts Catalog, Closed Cooling Systems (Bravo) to order the
specified Yfitting, seawater supply bulk hose, and hose clamps that
meets MerCruiser specifications. 1. Cut a 101.6 mm (4 in.) leneth
piece of the supply hose and install it to the seawater pump inlet
and the Yfitting port. 2. Install a seawater supply hose to the
Yfitting port and the sterndrive's water inlet at the transom. Cut
off any excess hose as needed. 3. Install a seawater supply hose to
the Yfitting port and the throughthehull or throughthetransom
seawater pickup. Cut off any excess hose as needed. 4. Properly
secure all hoses to all fittings to prevent water leaking into the
boat.
Installing the Seawater Supply HoseFor engine models not using
throughthehull or throughthetransom seawater pickup: 1. If
applicable, remove the Yfitting at the seawater pump inlet. 2.
Install a seawater supply hose that meets MerCruiser specifications
to the engine's seawater pump inlet. 3. Route the seawater supply
hose directly to the seawater inlet fitting on the transom. Cut off
any excess hose as needed. 4. Properly secure the hose at both ends
to prevent water leaking into the boat. NOTE: For models not
factoryequipped with a seawater supply hose, refer to the Mercury
Parts Catalog, Standard Cooling Systems (Bravo) to order the
specified bulk hose, hose clamps, and
quick connect fittings that meet MerCruiser specifications.
NOTE: For models with quick connection fittings and pull test
information, refer to Section 6, Seawater Inlet Fitting Connection
.
90-899883178 NOVEMBER 2007
Page 9 / 24
COOLING SYSTEM
SECTION - 5
Closed CoolingDescriptionClosed cooling is a standard feature on
some models and is available as an accessory or a factory installed
option on others. When closed cooling is used, a mixture of
antifreeze and water is circulated through the water jackets in the
engine block, cylinder heads, andon some applicationsthe exhaust
manifolds to dissipate the heat. Refer to Water Flow Diagrams. This
coolant is then passed though a heat exchanger. Here the coolant
rejects heat to seawater (water in which the boat is being
operated), which is simultaneously being passed through the
exchanger. The heat is then carried away by the seawater and
discharged overboard via the exhaust elbows. The design of the heat
exchanger allows for the transfer of heat, while ensuring that the
two coolants are separated. In this manner, the expensive engine
components are never exposed to seawater, which can be corrosive in
salty, polluted, or mineral laden water areas. Mercury MerCruiser's
closed cooling systems are developed by the same people who design
our engines to ensure compatibility and the same high quality
standards. Our systems employ several exclusive features to provide
unsurpassed cooling efficiency and durability. An exclusive
doubleacting thermostat is used on V6 and V8 models, which provides
increased coolant velocity through the engine and heat exchanger to
prevent hot spots and improve performance. Mercury MerCruiser's
heat exchangers also incorporate several stateoftheart designs to
enhance the heat transfer between the coolants for an additional
margin of cooling capacity. Features like these allow our systems
to continually operate at WOT in water temperatures up to 38 C (100
F), where most aftermarket systems fall short of this mark. This
additional cooling capacity translates into longer cooling system
life with fewer problems regardless of where the boat is operated.
Contact your sales representative to order your closed cooling
systems factory installed or refer to the Mercury Precision Parts
and Accessories Guide to obtain the part numbers for the accessory
kits. The term full closed cooling, also known as full fresh water
cooled or full FWC refers to the use of an ethylene glycol mixture
in the engine and the exhaust water jackets. The ethylene glycol
coolant mixture is circulated through the exhaust cooling passages
as well as the engine cooling passages.
Antifreeze Recommendations
NOTICEUsing propylene glycol antifreeze in the closed cooling
system can damage the cooling system or the engine. Fill the closed
cooling system with an ethylene glycol antifreeze solution suitable
to the lowest temperature to which the engine will be exposed.
Factory installed closed cooling systems come filled with an
extended life antifreeze. This coolant allows for a service
interval of 5 years or 1000 hours (whichever occurs first), versus
2 years or 400 hours for standard antifreeze. When adding coolant
to these systems (i.e. when filling coolant recovery bottle,
installing hot water heater), we recommend that only an
extendedlife antifreeze be used. Mixing this coolant with even a
small amount of regular antifreeze will require that the service
interval be reduced 2 years. If you are installing closed cooling
kits at your facility, we would also encourage you to use the
extended Life coolant to allow your customer to take advantage of
the reduced maintenance costs. Premixed extended life coolant is
available from Quicksilver or can be purchased at most automotive
stores and other locations where antifreeze is sold. Extendedlife
coolant is available from Texaco under the name Havoline Extended
Life Dex Cool. Prestone also offers a version of this antifreeze
called Extended Life 5/100. Only coolants that state that they are
compatible with Dex Cool should be used. Extendedlife coolants can
be identified by their orange color (vs. green for standard
coolant) and their corresponding orange cap on the container. All
antifreeze should be mixed 50/50 with pure water (Quicksilver
coolant is already premixed). If installing closed cooling kits at
your facility, be sure to observe the special filling procedure in
the installation instructions.Closed Cooling System Capacity
Page 10 / 24
90-899883178 NOVEMBER 2007
SECTION - 5 8.1S Models All Other Models 18 liters (19 quarts)
19 liters (20 quarts)
COOLING SYSTEM
Cool