136
FUEL SYSTEM
COMPONENTS
Fuel Reservoir
The vapor separator accumulates fuel in an inter-
nal fuel reservoir and supplies fuel to the electric
circulation p ump. It is water-cooled to e nhance
vapor separating capabilities.
Cooling
Water is use d to cool the f uel as it flo ws through
the vapor sep arator. Th e cooling p assage of the
separator self-drains when the ou tboard is sto red
vertically. Refer to HOSE ROUTING AND WATER
FLOW DIAGRAM 3.3 L on p. 184.
Venting
The fuel vapor vent regulates fuel vapor pressure
in the reservoir.
The vapor separator vent is opened and closed by
a float valve. The float valve moves relative to the
fuel level in the fuel chamb er. Hot fuel causes an
increase in vapor pressure. This results in a lower
fuel level in the vapor sep arator. The float valve
drops and the vent opens. This allows fuel va por
to flow t o the int ake manifold through the ve nt
hose.
As the vapor pressu re in the va por sep arator
decreases, the fuel level begins to in crease. An
increase in the fuel level raises the float valve and
the vent closes.
Pressure Regulator
The fuel pressure regulator helps maintain consis-
tent fuel pressure in the fuel system.
Fuel returning from the injecto rs ente rs the fue l
chamber o f t he vapor sep arator th rough a pres-
sure regu lator. The p ressure reg ulator ma intains
approximately 20 to 30 psi (138 to 207 kPa) of fuel
pressure in the high pressure side of the fuel sys-
tem.
Fuel Circulation Pump
The fuel circulation pump is an electric high pres-
sure fuel pump.
Fuel Supply
The pump is mounted to the vap or separator and
draws fuel from the fuel chamber. It pumps pres-
surized fuel throu gh a fuel su pply manifold co n-
nected to the fuel injectors.
Electrical Circuit
The circulation pu mp is co ntrolled by the EMM
and ope rates on the 12 V circuit. The circu lation
pump is activated momentarily wh en the EMM
powers up. The EMM controls pump opera tion by
rapidly connecting and disconnecting the pump’ s
internal coil to ground.
1. Vent 004187
1. Vent hose connection to intake 004188
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