Mercury 40 FourStroke Service Manual page 168

FUEL PUMP
Fuel Pump Operation
S/N OG960499 and Below
NOTE: S/N OG960499 and below can be updated with the new water cooled fuel pump.
The fuel pump is a diaphragm pump which is mechanically driven off of the rocker arm. The
pump base insulates the fuel pump from the heat of the engine block.
If the engine runs out of fuel, or has a restriction (on the inlet side of the pump) preventing
adequate fuel flow, the pump will make a "clicking" noise.
FIRE AND EXPLOSION HAZARD. Observe fire prevention rules, particularly NO
SMOKING. Before servicing any part of the fuel system, disconnect electrical sys-
tem at the battery. Drain the fuel system completely. Use an approved container to
collect and store fuel. Wipe up any spillage immediately. Materials used to contain
spillage must be disposed of in an approved receptacle. Any fuel system service
must be performed in a well ventilated area
FUEL LEAKAGE FROM ANY PART OF THE FUEL SYSTEM CAN BE A FIRE AND EX-
PLOSION HAZARD WHICH CAN CAUSE SERIOUS BODILY INJURY OR DEATH.
Careful periodic inspection of the entire fuel system is mandatory, particularly after
engine storage. All fuel components, including fuel tanks, whether plastic, metal,
or fiberglass, fuel lines, primer bulbs, fittings, swelling, and must be inspected for
corrosion. Any sign of leakage or deterioration necessitates replacement before
further engine operation.
S/N OG960500 and Up
The fuel pump is a diaphragm pump which is mechanically driven off of the rocker arm. The
pump base insulates the fuel pump from the heat of the engine block. The fuel pump is water
cooled to help prevent vapor lock by cooling the fuel.
If the engine runs out of fuel, or has a restriction (on the inlet side of the pump) preventing
adequate fuel flow, the pump will make a "clicking" noise.
a -
b -
c -
d -
Page 3A-6
c
Fuel From Filter/Tank
Fuel Outlet to Carburetors
Water Inlet From Exhaust Cover
Water Outlet to Tell-tale
WARNING
.
b
a
d
90-857046R1 NOVEMBER 2001