FILTER GP-WATER SEP & FUEL 4238524 - Caterpillar

General Operation of the Fuel System
Illustration 1 g00758646
The six cylinder engine is shown. (1) Air inlet heater (2) Fuel transfer pump (3) Fuel supply line from the fuel tank (4) Fuel injection nozzle (5) Fuel return line (6) Engine (7) Fuel injection pump (8) Fuel return line from fuel injection pump (9) Fuel supply line to fuel injection pump (10) Vent for purging air from the fuel (11) Fuel filters (12) Fuel return line to the fuel tankWhen the engine is cranking, the fuel is pulled from the fuel tank through the water separator (if equipped) by the fuel transfer pump (2). When the fuel goes through the water separator, any water in the fuel will go to the bottom of the bowl. The fuel transfer pump sends the fuel at a low pressure to the fuel filters (11). From the fuel filters, the fuel goes through the fuel supply line (9) to the fuel injection pump (7) .The fuel injection pump sends fuel through the high pressure fuel lines to each of the fuel injection nozzles (4). The fuel injection nozzle sprays fuel into the cylinder. Fuel which is not used by the fuel injection pump goes through the fuel return line (5) to the fuel tank (12) .The fuel injection pump needs fuel for lubrication. The precision parts of the pump are easily damaged. For this reason, the engine must not be started until the fuel injection pump is full of fuel that is free of air.The system must be primed when any part of the system is drained of fuel. When the following service items are performed, the fuel system must be primed:
The fuel filter is changed.
The fuel line is removed.
The fuel injection pump is removed.General Components
Illustration 2 g00758795
The fuel system components for the 3056 Marine Generator Set engine are shown. The left side of the engine is shown. (1) Fuel injection pump (2) Fuel injection nozzle (3) Fuel filter base (4) Fuel filters
Illustration 3 g00758800
The fuel system components for the 3056 Marine Generator Set engine are shown. The right side of the engine is shown. (5) Air inlet heater (6) Fuel transfer pumpThere is a small filter screen in the fuel transfer pump (6) on the 3056 engine. The pump has a lever which is manually operated in order to prime the fuel system by removing the air. In order to release air from the system, there is a vent plug on the top of the fuel filter base (3) .The air inlet heater (5) is an electrically operated device. The air inlet heater ignites a controlled amount of diesel fuel