The fuel system (Fig. 1) includes the fuel injectors, fuel pipes (inlet and outlet), fuel manifolds (integral with the
cylinder head), fuel pump, fuel strainer, fuel filter, and fuel lines.
Fuel is drawn from the supply tank through the fuel strainer and enters the fuel pump at the inlet side. Leaving
the pump under pressure, the fuel is forced through the fuel filter and into the inlet fuel manifold, then through
fuel pipes into the inlet side of each injector.
The fuel manifolds are identified by the words IN (top passage) and OUT (bottom passage), which are cast in
several places in the side of the cylinder head. This aids installation of the fuel lines.
Surplus fuel returns from the outlet side of the injectors to the fuel manifold and then back to the supply tank.
All engines are equipped with a restrictive fitting in the fuel outlet manifold to maintain fuel system pressure.
Refer to Crankshaft Oil Seals for the size fitting required.
Figure 1. Typical Fuel System for In-Line Engines
A check valve may be installed in the supply line between the fuel tank and the fuel strainer to prevent fuel
from draining back when the engine is shut down.