FUEL SYSTEM
FUEL PUMP
5
A
Index
Table of Contents
Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacement Parts Warning . . . . . . . . . . . . . .
Torque Specifications . . . . . . . . . . . . . . . . . . . .
Tools/Lubricants/Sealants . . . . . . . . . . . . . . . .
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . .
Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Delivery System . . . . . . . . . . . . . . . . . . . .
Recommendations . . . . . . . . . . . . . . . . . . . .
Description . . . . . . . . . . . . . . . . . . . . . . . . . .
Page
5A - 1
5A - 1
5A - 1
5A - 1
5A - 1
5A - 2
5A - 2
5A - 2
5A - 2
Fuel System Components (Typical) . . . . . . . .
Water Separating Fuel Filter . . . . . . . . . . . . . .
Replacement . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Pump Fuel Filter . . . . . . . . . . . . . . . . . . . .
Replacement . . . . . . . . . . . . . . . . . . . . . . . . .
Testing Fuel Pump . . . . . . . . . . . . . . . . . . . . . .
Fuel Pump Replacement . . . . . . . . . . . . . . . . .
Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Page
5A - 3
5A - 3
5A - 3
5A - 4
5A - 4
5A - 4
5A - 5
5A - 5
NOTICE
For information and procedures on troubleshooting, refer to SECTION 1C.
Index
5A- -0FUEL
DELIVERY
5A
- FUEL
PUMP SYSTEM
90-816462 2-695
2-695
90-816462
Identification
Torque Specifications
Description
Fuel Inlet and
Outlet Fittings
Lb. Ft.
N⋅m
Tighten finger tight then
1-3/4 to 2-1/4 turns with wrench.
(See Note)
Fuel Line to
Fuel Outlet
Fitting
Fuel Pump to
Block
Securely
20
27
NOTE: Apply #592 Loctite Pipe Sealant with Teflon. Do not
use Teflon Tape.
Tools/Lubricants/Sealants
Carter Fuel Pump
Description
Replacement Parts Warning
! WARNING
Electrical, ignition and fuel system components
on your MerCruiser are designed and manufactured to comply with U.S. Coast Guard Rules and
Regulations to minimize risks of fire and explosion.
Use of replacement electrical, ignition or fuel system components, which do not comply with
these rules and regulations, could result in a fire
or explosion hazard and should be avoided.
Part Number
Fuel Pressure Gauge
91-16850A1
Quicksilver Perfect Seal
92-34227-1
Quicksilver Needle
Bearing Grease
92-42649A1
Obtain Locally
Loctite Pipe Sealant
with TEFLON
Specifications
Type of Fuel Pump
Carter
Pump Pressure
(1800 RPM)
5-1/4 - 6-1/4 PSI
(36-44 kPa)
! WARNING
Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into fuel filter base
can crack casting and/or cause a fuel leak.
•
Apply #592 Loctite Pipe Sealant with Teflon to
threads of brass fitting or plug. DO NOT USE
TEFLON TAPE.
•
Thread brass fitting or plug into fuel filter base
until finger tight.
•
Tighten fitting or plug an additional 1-3/4 to
2-1/4 turns using a wrench. DO NOT
OVER-TIGHTEN.
•
Install fuel line. To prevent over-tightening,
hold brass fitting with suitable wrench and
tighten fuel line connectors securely.
•
Check for fuel leaks.
Index
90-816462 2-695
FUEL PUMP - 5A - 1
Precautions
! WARNING
Always disconnect battery cables from battery
BEFORE working on fuel system to prevent fire
or explosion.
! WARNING
Be careful when changing fuel system components; gasoline is extremely flammable and highly explosive under certain conditions. Be sure
that ignition key is OFF. DO NOT smoke or allow
sources of spark or flame in the area while changing fuel filters. Wipe up any spilled fuel immediately.
! WARNING
Make sure that no fuel leaks exist before closing
engine hatch.
! CAUTION
DO NOT operate engine without cooling water being supplied to seawater pickup pump, or pump
impeller will be damaged and subsequent overheating damage may result.
! WARNING
Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into fuel filter base
can crack casting and/or cause a fuel leak.
•
Apply #592 Loctite Pipe Sealant with Teflon to
threads of brass fitting or plug. DO NOT USE
TEFLON TAPE.
•
Thread brass fitting or plug into fuel filter base
until finger tight.
•
Tighten fitting or plug an additional 1-3/4 to
2-1/4 turns using a wrench. DO NOT
OVER-TIGHTEN.
•
Install fuel line. To prevent over-tightening,
hold brass fitting with suitable wrench and
tighten fuel line connectors securely.
•
Check for fuel leaks.
Fuel Delivery System
Recommendations
! WARNING
Boating industry standards (BIA, ABYC, etc.) federal standards and Coast Guard regulations
MUST BE adhered to when installing fuel delivery
system.
When designing and installing fuel delivery system,
the following information MUST BE observed:
1. Fuel tank should be mounted below carburetor
level, if possible. If tank is mounted above carburetor level, gravity feed may cause carburetor fuel
inlet needle to unseat, and flooding may result.
2. Fuel pickup should be at least 1 in. (25 mm) from
the bottom of the fuel tank to prevent picking up
water or other impurities.
3. Fuel lines used MUST BE Coast Guard approved
(USCG type A) and MUST NOT BE SMALLER
THAN 3/8 in. (9.5 mm) I.D. On installations where
long lines or numerous fittings are required, larger size lines should be used.
4. Fuel line should be installed free of stress and
firmly secured to prevent vibration and/or chafing.
5. Sharp bends in fuel line should be avoided.
6. A flexible fuel line must be used to connect fuel
line to engine to absorb deflection when engine is
running.
Description
The fuel system consists of fuel tank(s), a water separating fuel filter, an electric fuel pump and a carburetor.
The fuel is stored in the fuel tank. When the fuel pump
is energized by turning on ignition switch, fuel is
drawn from the fuel tank, through the water separating filter, by the electric fuel pump.
The fuel is pushed through the fuel line to the carburetor where it is metered and supplied to the engine.
Index
5A - 2 - FUEL PUMP
90-816462 2-695
Filter should be replaced when fuel flow is restricted
or filter flow is questionable. DO NOT attempt to flush
out filter.
Fuel System Components
FUEL SYSTEM
Replacement
i
NOTICE
Refer to “Precautions,” in this section, BEFORE proceeding.
g
b
c
f
d
h
1. Disconnect battery cables from battery.
e
a
50830
3. Lubricate sealing ring(s) of new filter with SAE engine oil.
Typical
a
b
c
d
e
f
g
h
i
-
2. Remove fuel filter from base. A filter wrench may
be needed to loosen element.
Fuel Tank
Anti Siphon Valve
Water Separating Fuel Filter
Fuel Pump
Carburetor
Fuel Filter
Vent Hose
Fuel Line
Sight Tube
4. Install new filter, tightening securely by hand.
5. Reconnect battery cables. Make sure water is
supplied to cooling system and start engine.
Check for fuel leaks.
Water Separating Fuel Filter
(If So Equipped)
The fuel filter consists of the fuel filter base and filter element.
a
a
c
b
c
72678
a - Filter Base/Mounting Bracket
b - Filter Element
c - Sealing Ring
b
72678
a - Filter Mounting Bracket
b - Filter Element
c - Sealing Ring
Index
90-816462 2-695
FUEL PUMP - 5A - 3
9. Check for gasoline leaks.
Fuel Pump Fuel Filter
NOTICE
Refer to “Precautions,” in this section, BEFORE proceeding.
10. If leaks exist, STOP ENGINE and recheck connections.
Testing Fuel Pump
Replacement
INSPECTION
Fuel pumps are equipped with a sight tube. Any evidence of fuel in the sight tube indicates a ruptured diaphragm and fuel pump must be replaced immediately.
NOTICE
Refer to “Precautions,” in this section, BEFORE proceeding.
1. Disconnect battery cables from battery.
2. Remove fuel line from carburetor or outlet side of
fuel pump.
3. Install Fuel Pressure Connector (91-18078) to
carburetor or fuel pump and reinstall fuel line.
Tighten connector and fuel line securely.
4. Connect fuel pressure test gauge to connector.
a
a
b
50738
a - Sight Tube
b - Fuel Fitting
NOTE: This fuel pump must be replaced as an assembly; it is not repairable with a diaphragm kit.
c
1. Disconnect battery cables from battery.
b
! CAUTION
Plug fuel supply hose after removal to prevent
fuel from leaking into boat.
2. Remove safety wire.
3. Loosen screw from filter bowl bail and release bail
from fuel pump housing.
4. Remove bowl, filter element, spring, and gasket
from fuel pump.
5. Install new filter.
6. Tighten retaining screw securely.
71561
a – Fits into Carburetor
b - Fuel Line Connection
c - Fuel Gauge Barb
5. Reconnect battery cables, start engine, and run
at idle, making sure water is supplied to the cooling system.
6. Fuel pressure should be within specifications. If
not, replace fuel pump.
7. Remove fuel pressure gauge and connector tool.
Reconnect fuel line to fuel pump.
7. Install safety wire and tighten securely.
8. Start and run engine.
Index
5A - 4 - FUEL PUMP
90-816462 2-695
•
Fuel Pump Replacement
Check for fuel leaks.
5. Install fuel outlet fitting (from old pump) into fuel
pump.
Removal
1. Remove fuel inlet and outlet lines at fuel pump.
6. Install fuel line to fuel outlet fitting. Tighten securely.
2. Remove sight tube.
7. Install fuel inlet fitting to fuel pump.
8. Install sight tube and fuel supply line.
9. Start engine and check for fuel leaks.
a
b
50738
a - Sight Tube
b - Fuel Fitting
3. Remove 2 fuel pump mounting bolts and lockwashers, pump and gasket.
! CAUTION
Plug fuel lines after disconnecting from fuel
pump to eliminate any chance of fuel siphoning
into bilge.
4. Install new gasket (coat both sides with Perfect
Seal) on fuel pump. Install pump, and torque
mounting bolts to specifications.
! WARNING
Avoid gasoline fire or explosion. Improper installation of brass fittings or plugs into fuel filter base
can crack casting and/or cause a fuel leak.
•
Apply #592 Loctite Pipe Sealant with Teflon to
threads of brass fitting or plug. DO NOT USE
TEFLON TAPE.
•
Thread brass fitting or plug into fuel filter base
until finger tight.
•
Tighten fitting or plug an additional 1-3/4 to
2-1/4 turns using a wrench. DO NOT
OVER-TIGHTEN.
•
Install fuel line. To prevent over-tightening,
hold brass fitting with suitable wrench and
tighten fuel line connectors securely.
Index
90-816462 2-695
FUEL PUMP - 5A - 5