Mercury MERCRUISER User manual

Service Manual #40
90-865376
Gen III Cool Fuel Supplement to #30 & 31
Gen III Cool Fuel Supplement to #30 & 31
©2004, Mercury Marine. All rights reserved. Printed in U.S.A. 90-865376 DECEMBER 2004
SM #40.qxd 11/30/2004 3:24 PM Page 1

Page i
Notice to Users of This Manual
Throughout this publication, Dangers, Warnings and Cautions (accompanied by the
International HAZARD Symbol
!
) are used to alert the mechanic to special instructions
concerning a particular service or operation that may be hazardous if performed incorrectly
or carelessly. 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.
!
DANGER
DANGER - indicates an imminently hazardous situation that, if not avoided, will result in
death or serious injury.
!
WARNING
WARNING - indicates a potentially hazardous situation that, if not avoided, could result
in death or serious injury.
!
CAUTION
CAUTION - indicates a potentially hazardous situation that, if not avoided, may result in
minor or moderate injury or property damage. It may also be used to alert against unsafe
practices.
This manual has been written and published by the Service Department of Mercury Marine
to aid our dealers’ mechanics and company service personnel when servicing the products
described herein. We reserve the right to make changes to this manual without prior
notification.
© 2004, Mercury Marine
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.
It is assumed that these personnel are familiar with marine product servicing procedures.
Furthermore, it is assumed that they have been trained in the recommended service
procedures of Mercury Marine Power Products, including the use of mechanics’ common
hand tools and the special Mercury Marine or recommended tools from other suppliers.
We could not possibly know of and advise the marine trade of all conceivable procedures
and of the possible hazards and/or results of each method. Therefore, anyone who uses
a service procedure and/or tool, which is not recommended by the manufacturer, first must
completely satisfy himself that neither his nor the products safety will be endangered.
All information, illustrations and specifications contained in this manual are based on the
latest product information available at the time of publication. As required, revisions to this
manual will be sent to all dealers contracted by us to sell and/or service these products.
Refer to dealer service bulletins, operation maintenance and warranty manuals and
installation manuals for other pertinent information concerning the products described in
this manual.

Page ii
Precautions
It should be kept in mind, while working on the product, that the electrical and ignition
systems are capable of violent and damaging short circuits or severe electrical shocks.
When performing any work where electrical terminals could possibly be grounded or
touched by the mechanic, the battery cables should be disconnected at the battery.
Any time the intake or exhaust openings are exposed during service they should be
covered to protect against accidental entrance of foreign material which could enter the
cylinders and cause extensive internal damage when the engine is started.
It is important to note, during any maintenance procedure replacement fasteners must have
the same measurements and strength as those removed. Numbers on the heads of the
metric bolts and on the surfaces of metric nuts indicate their strength. American bolts use
radial lines for this purpose, while most American nuts do not have strength markings.
Mismatched or incorrect fasteners can result in damage or malfunction, or possibly
personal injury. Therefore, fasteners removed should be saved for reuse in the same
locations whenever possible. Where the fasteners are not satisfactory for reuse, care
should be taken to select a replacement that matches the original.
Replacement Parts
Use of parts other than the recommended service replacement parts, will void the warranty
on those parts that are damaged as a result.
!
WARNING
Electrical, ignition and fuel system components on Mercury Marine Power Products are
designed and manufactured to comply with U.S. Coast Guard Rules and Regulations to
minimize risks of fire or explosion.
Use of replacement electrical, ignition or fuel system components, which do not comply
to these rules and regulations, could result in a fire or explosion hazard and should be
avoided.
When servicing the electrical, ignition and fuel systems, it is extremely important that all
components are properly installed and tightened. If not, any electrical or ignition
component opening would permit sparks to ignite fuel vapors from fuel system leaks, if
they existed.
Cleanliness and Care of Product
A Mercury Marine Power Product is a combination of many machined, honed, polished and
lapped surfaces with tolerances that are measured in the ten thousands of an inch/mm.
When any product component is serviced, care and cleanliness are important. Throughout
this manual, it should be understood that proper cleaning and protection of machined
surfaces and friction areas is a part of the repair procedure. This is considered standard
shop practice even if not specifically stated.
Whenever components are removed for service, they should be retained in order. At the
time of installation, they should be installed in the same locations and with the same mating
surfaces as when removed.
Personnel should not work on or under an engine that is suspended. Engines should be
attached to work stands, or lowered to ground as soon as possible.

Page iii
Manual Outline
1 - Important Information
A - General Information
B - Maintenance
2 - Gen III Cool Fuel Module All Models
A - Gen III Cool Fuel Module Removal and
Disassembly
B - Gen III Cool Fuel Module Assembly and
Installation
3 - Fuel System
A - Troubleshooting and Repair
B - Fuel Flow Diagram
4 - Cooling System
A - Coolant and Water Flow Diagrams
Important Information 1
Gen III Cool Fuel Module All Models 2
Fuel System 3
Cooling System 4

General Information
90-865376 NOVEMBER 2004 Page 1A-1
1
A
Important Information
Section 1A - General Information
Table of Contents
Introduction......................................................1A-2 Gen III Cool Fuel Module Exploded View........1A-3

General Information
Page 1A-2 90-865376 NOVEMBER 2004
Introduction
This supplement is designed as a service guide for the models previously listed. It provides
specific information, including procedures for disassembly, inspection, assembly, and
Installation to enable dealers and service mechanics to diagnose and repair the Generation
III Cool Fuel Module.
Before attempting repairs it is suggested that the procedure first be read through to gain
knowledge of the methods and tools used and the cautions and warnings required for
safety.

General Information
90-865376 NOVEMBER 2004 Page 1A-3
Gen III Cool Fuel Module Exploded View
2
3
4
5
7
8
13
1
14
15
16
17 18
19
20
21
22
23
24
6
9
11
10
12
8810
1 - Pressure regulator screws
2 - Pressure regulator
3 - Screws, Top cover
4 - Top cover
5 - Seal, Top cover
6 - Fuel pump outlet seal
7 - High-pressure fuel pump
8 - Isolator, High-pressure fuel pump
9 - Isolator, Low-pressure fuel pump
10 - Low-pressure fuel pump
11 - Inlet seal, Low-pressure fuel
pump
12 - Cool Fuel Module housing
13 - Stud
14 - Screw, Wire harness retainer
15 - Wire harness retainer
16 - Wire harness
17 - 2-pin electrical connector (plug)
18 - Screws, Filter cap
19 - Filter cap
20 - O-ring
21 - Fuel filter
22 - Seal, Filter cup
23 - Filter cup
24 - Filter disc

Maintenance
90-865376 NOVEMBER 2004 Page 1B-1
1
B
Important Information
Section 1B - Maintenance
Table of Contents
Changing Water Separating Fuel Filter Element
.........................................................................1B-2

Maintenance
Page 1B-2 90-865376 NOVEMBER 2004
Changing Water Separating Fuel Filter Element
!
WARNING
Avoid Fire or Explosion: The fuel injection system is pressurized during operation. Use
care when removing the water separating fuel filter. Allow the engine to cool down before
attempting to remove the water separating fuel filter in the following procedure.
!
WARNING
Be careful when changing the water separating fuel filter. Gasoline is extremely
flammable and highly explosive under certain conditions. Ensure the ignition key is
"OFF". Do not smoke or allow spark or open flame in the area when changing the fuel
filter. Wipe up any spilled fuel immediately.
!
WARNING
Ensure that no fuel leaks exist before closing the engine hatch.
1. Allow the engine to cool down.
2. Close fuel supply valve, if equipped.
NOTE: Mercury MerCruiser recommends that the engine be shut off for 12 hours prior to
filter removal.
3. Disconnect the Cool Fuel Module harness from the engine wiring harness.
4. Turn the key switch to the start position and allow the starter to operate for 5 seconds
to relieve fuel system pressure.
5. Turn key switch to off position.
6. Unseat the filter assembly by grasping the filter assembly handle and pulling upward.
Do not completely remove the filter assembly from the Cool Fuel Module at this time.

Maintenance
90-865376 NOVEMBER 2004 Page 1B-3
7. Loosen each filter assembly retaining screw until the screw is disengaged from the Cool
Fuel Module. Do not remove the filter assembly retaining screws from the filter cap.
d
a
b
c
e
f
g
h
8837
a - Cool Fuel Module
b - Cool Fuel Module harness
c - Filter cap
d - Filter assembly retaining screw
e - Fuel filter element
f - Filter cup
g - Cool Fuel Module filter reservoir
h - Seal, Filter cup
8. Allow any fuel that may be in the filter assembly to drain out through the bottom of the
filter assembly and into the Cool Fuel Module filter reservoir.
9. Remove the filter cup from the filter cap by grasping the filter cap and rotating it in a
clockwise direction while holding the filter cup stationary.
10. Remove the used water separating fuel filter element from the filter cup, place it in a
clean, approved container.
11. Dispose of any water or debris that may be in the filter cup.
12. Install a new water separating fuel filter element into the filter cup. Push the element
into the cup until completely seated.
13. Install new O-ring on the filter cup.
14. Attach the filter cap to the filter cup by grasping the filter cap and rotating it in a counter
clockwise direction while holding the filter cup stationary, until the filter cap locks
securely into place.
15. Install the fuel filter assembly slowly into the Cool Fuel Module to prevent spilling fuel,
and align the screws retained in the filter cap with the screw holes in the Cool Fuel
Module. Tighten the filter assembly retaining screws until hand tight.
16. Ensure that the filter cap is firmly seated against the Cool Fuel Module and torque each
filter assembly retaining screw.
17. Open fuel supply valve, if equipped.

Maintenance
Page 1B-4 90-865376 NOVEMBER 2004
Description Nm lb. in. lb. ft.
Filter assembly retaining screw 6 53
18. Reconnect the Cool Fuel Module harness to the engine wiring harness.
19. Supply cooling water to the engine.
20. Properly ventilate the engine compartment.
!
WARNING
Avoid serious injury or death due to FIRE or EXPLOSION. Ensure that the engine
compartment is well ventilated and that no gasoline vapors are present to prevent the
possibility of a FIRE or EXPLOSION.
!
WARNING
Ensure that no fuel leaks exist before closing the engine hatch.
21. Run the engine and check for any leaks. Stop the engine immediately if any leak exists,
and correct before continuing.

Gen III Cool Fuel Module Removal and Disassembly
90-865376 NOVEMBER 2004 Page 2A-1
2
A
Gen III Cool Fuel Module All Models
Section 2A - Gen III Cool Fuel Module Removal and Disassembly
Table of Contents
Gen III Cool Fuel Module Removal..................2A-2 Gen III Cool Fuel Module Disassembly............2A-5

Gen III Cool Fuel Module Removal and Disassembly
Page 2A-2 90-865376 NOVEMBER 2004
Gen III Cool Fuel Module Removal
!
WARNING
Always disconnect battery cables from battery before working on fuel system to prevent
fire or explosion.
!
WARNING
Fuel vapors can be present in the engine compartment. Avoid injury or power package
damage caused by fuel vapors or explosion. Always ventilate the engine compartment
prior to servicing the power package.
!
CAUTION
Pressurized fuel system! Release all pressure before servicing any part of the fuel
system. This system can build pressure if the engine has not run for an extended period
of time. If the fuel system is not relieved of pressure, fuel and vapors may be expelled at
a significant velocity. Always protect your eyes and skin from pressurized fuel and vapors
when servicing the fuel system.
1. Close the fuel supply valve.
2. Relieve fuel system pressure as follows:
a. Connect fuel pressure Gauge kit to Shrader valve.
Fuel pressure gauge kit 91-881883A2
b
a
c
8786
View from starboard side of engine looking forward
a - Throttle body and flame arrestor
b - Fuel rail
c - Shrader valve
b. Place fuel pressure gauge relief line into an approved container.
c. Open fuel pressure gauge relief valve to relieve pressure.
3. Close the seacock.
4. Disconnect negative (-) battery cable from battery (usually black).
5. Disconnect positive (+) battery cable from battery (usually red).
6. Disconnect Cool Fuel Module 2-pin harness connector.
7. Disconnect fuel supply (inlet) hose and plug hose.

Gen III Cool Fuel Module Removal and Disassembly
90-865376 NOVEMBER 2004 Page 2A-3
8. Disconnect fuel pressure regulator vacuum hose from fuel pressure regulator on Cool
Fuel Module.
8724
b
a
c
c
a - Fuel pressure regulator
b - Fuel pressure regulator hose
nipple
c - Fuel pressure regulator vacuum
hose
9. Loosen nut on cooling hose bracket and remove cooling hoses from Cool Fuel Module.
a
b
8783
a - Cooling hoses b - Bracket nut

Gen III Cool Fuel Module Removal and Disassembly
Page 2A-4 90-865376 NOVEMBER 2004
10. Remove the fuel outlet line retainer screw.
a
b
8784
a - Fuel outlet line b - Fuel outlet screw
a
8785
a - Fuel outlet line retainer screw
11. Carefully pull the fuel outlet line straight out from the module and plug the line.
a
b
8755
a - Fuel outlet line b - O-ring
12. Remove Cool Fuel Module mounting brackets from engine.

Gen III Cool Fuel Module Removal and Disassembly
90-865376 NOVEMBER 2004 Page 2A-5
13. Carefully remove the Cool Fuel Module from the engine.
Gen III Cool Fuel Module Disassembly
NOTE: Retain all fasteners and hardware unless instructed otherwise.
IMPORTANT: Do not remove the fuel inlet adapter fitting.
a
8269
a - Fuel inlet adapter fitting.
1. Remove Cool Fuel Module from engine. Refer to Gen III Cool Fuel Module Removal.
2. Remove primary mounting bracket from Cool Fuel Module.
8795
Primary Bracket

Gen III Cool Fuel Module Removal and Disassembly
Page 2A-6 90-865376 NOVEMBER 2004
3. Remove support bracket from Cool Fuel Module.
8796
Support Bracket
4. Remove filter assembly. Refer to Section 1B of this manual for filter removal procedure.
5. Remove 6 screws holding top cover.
c
a
b
8706
a - Gen III Cool Fuel Module
b - Top cover
c - Top cover screws (not all shown)

Gen III Cool Fuel Module Removal and Disassembly
90-865376 NOVEMBER 2004 Page 2A-7
6. Pull top cover straight up.
a
d
b
c
a - Gen III Cool Fuel Module
b - Top cover
c - Low-pressure fuel pump
d - High-pressure fuel pump
7. Disconnect electrical connections from the low-pressure and high-pressure pumps and
remove the pumps from the top cover.
a
b
c
8711
a - Top cover
b - Low-pressure fuel pump electrical
connections
c - High-pressure fuel pump electrical
connector

Gen III Cool Fuel Module Removal and Disassembly
Page 2A-8 90-865376 NOVEMBER 2004
8. Remove seals and isolators from fuel pumps.
a
b
c
d
8739
Low-pressure Fuel Pump
a - Low-pressure fuel pump
b - Outlet seal
c - Inlet seal
d - Isolator
a
b
c
8740
High-pressure Fuel Pump
a - High-pressure fuel pump
b - Isolator
c - Outlet seal
NOTE: Fuel inlet seal for low-pressure pump may not come out with the pump when pump
is removed from the Cool Fuel Module housing. Be sure to remove the seal from the
housing before low-pressure fuel pump installation.
9. Drain fuel from Gen III Cool Fuel Module into an approved container.

Gen III Cool Fuel Module Assembly and Installation
90-865376 NOVEMBER 2004 Page 2B-1
2
B
Gen III Cool Fuel Module All Models
Section 2B - Gen III Cool Fuel Module Assembly and Installation
Table of Contents
Gen III Cool Fuel Module Assembly................2B-2
Fuel Inlet Adapter Fitting...........................2B-2
Top Cover and Fuel Pumps .....................2B-2
Fuel Pressure Regulator...........................2B-7
Gen III Cool Fuel Module Installation...............2B-8