SENR9977 15 Systems Operation Section When the engine is operated, the fuel is pulled from the fuel tank (6) through the primary fuel filter/water separator (3) by the fuel transfer pump (2). When the fuel passes through the water separator, any water in the fuel will go to the bottom of the bowl. The fuel transfer pump is equipped with a secondary fuel filter. From the fuel priming pump, the fuel passes through the fuel supply line to the fuel injection pump (7). The fuel injection pump sends fuel through the high pressure fuel lines to the fuel injectors (1). The fuel injectors spray atomized fuel into the cylinders. The fuel injection pump needs fuel for lubrication.
The precision parts of the pump are easily damaged. The engine must not be operated until the fuel injection pump is full of fuel. The system must be primed when any part of the system is drained of fuel. The fuel system needs priming when a fuel filter is changed, and/or when a fuel line is removed, and/or when the fuel injection pump is replaced.