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| Illustration 1 | g00347597 |
Left side of the engine (1) Fuel supply line (2) Fuel transfer pump | |
Fuel transfer pump (2) is located on the left rear side of the front housing. The fuel transfer pump is powered by a spur gear that is mounted on the engine oil pump drive gear.
The fuel transfer pump has a check valve and a bypass valve. The check valve prevents fuel flow back through the fuel transfer pump when the fuel priming pump is used.
The fuel system components can be damaged by too much pressure. The bypass valve limits the maximum pressure of the fuel. The bypass valve will open the outlet side of the pump if the fuel pressure is greater than 700 kPa (100 psi). This helps prevent damage to the fuel system components.
The minimum pressure to the inlet of the fuel transfer pump is -20 kPa (-3 psi).
The fuel transfer pump circulates the fuel through the following components:
- Fuel supply tank
- Fuel filters
- Check valve
- Fuel supply manifold
- Fuel supply lines to the cylinder heads
- Fuel return manifold
- Fuel pressure control valve
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| Illustration 2 | g00360912 |
(3) Secondary fuel filter housing | |
Fuel from the supply tank is drawn through the primary fuel filter/water separator (if equipped) by the fuel transfer pump. The fuel flows through the secondary fuel filters and a check valve. The check valve prevents the fuel from flowing back into the fuel filter housing when the fuel filters are changed.
Use the fuel priming pump to force air from the fuel system after the fuel filters are changed. Also, the fuel priming pump must be used when the fuel lines are dry. For example, use the priming pump after an overhaul or other major fuel system maintenance.
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| Illustration 3 | g00877749 |
Fuel supply and fuel return lines | |
A fuel supply line is located on the right side of each cylinder head. A drilled passage in the cylinder head directs the fuel to a circular chamber around each fuel injector. The chamber is made by the mating fit of the O-ring seals on the outside of the fuel injector and the bore for the fuel injector in the cylinder head.
Only part of the fuel is used for injection. The remaining fuel flows through the chamber to a drilled passage on the left side of the cylinder head. This passage is connected by a fuel return line to the fuel return manifold. This constant flow of fuel around the fuel injectors helps cool the fuel injectors.
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| Illustration 4 | g00360913 |
Right side of the engine (4) Fuel pressure control valve | |
The fuel flows through the fuel return manifold to fuel pressure control valve (4). The fuel pressure control valve is located on the right side of the front housing. The fuel flows through the fuel pressure control valve. Then, the fuel flows back to the supply tank.
The fuel pressure control valve keeps the pressure in the fuel system at 450 kPa (65 psi) at 350 RPM and 700 kPa (100 psi) at 1050 RPM.