Installation manual

90-898305

1-64

Fuel

Fuel for the engine is stored in a typical fuel tank. A primer bulb is installed

into the fuel line to allow priming of the fuel system. A vapor separator

mounted diaphragm fuel pump draws fuel through the fuel line, primer bulb

and fuel pump assembly. The pump then pushes the fuel through a water

separating fuel filter. This filter removes any contaminates and water before

the fuel reaches the vapor separator. Fuel vapors are vented through the

bottom cowling into the atmosphere. The electric fuel pump is capable of

developing fuel pressures in excess of 744.6 kPa (108 psi). Fuel inside the rail

must remain pressurized at exactly 96.5 kPa (14 psi) over the air rail pressure

or the PCM (map) calibrations will be incorrect. Fuel from the vapor separator

is supplied to the top of the fuel rail. Fuel is stored inside the rail until an

injector opens. A fuel pressure regulator controls pressure in the fuel rail, and

allows excess fuel to return into the vapor separator. The fuel regulator not

only regulates fuel pressure but also regulates it at 96.5 kPa (14 psi) higher

than whatever the air rail pressure is. The fuel regulator diaphragm is held

closed with a spring that requires 96.5 kPa (14 psi) to force the diaphragm off

the diaphragm seat. The back side of the diaphragm is exposed to air rail

pressure. As the air rail pressure increases, the fuel pressure needed to open

the regulator will equally increase. Example: If there is 344.7 kPa (50 psi) of

air pressure on the air rail side of the diaphragm, 441.3 kPa (64 psi) of fuel

pressure will be required to open the regulator. The fuel rail is water cooled.

Oil

Oil in this engine is not mixed with the fuel before entering the combustion

chamber. Oil is stored inside an engine mounted reservoir.

A remote oil tank is available as an option. Crankcase pressure will force oil

from the remote oil tank into the oil reservoir on the front of the powerhead.

Oil will flow from the oil reservoir into the oil pump. The oil pump is a solenoid

design. It is activated by the PCM and includes 7 pistons with corresponding

discharge ports. The oil pump is mounted on the electrical plate. Each cylinder

is lubricated by one of the discharge ports. The oil is discharged into the

crankcase. The seventh passage connects to the hose that leads to the air

compressor for lubrication. Excess oil from the compressor returns into the

cylinder bores.

The PCM will change the discharge rate of the oil pump, depending upon

engine demand. The PCM will also pulse the pump on initial start up to fill the

oil passages eliminating the need to bleed the oil system. The PCM provides

additional oil for break-in, as determined by its internal clock. The oil ratio

varies with engine RPM and load.

Notes

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