C4.4 (Mech) Marine Generator Set MCS-3 Caterpillar

If air enters the fuel system, the air must be purged from the fuel system before the engine can be started. Air can enter the fuel system when the following events occur:

• The fuel tank is empty or the fuel tank has been partially drained.

• The low-pressure fuel lines are disconnected.

• A leak exists in the low-pressure fuel system.

• The fuel filter has been replaced.

Priming the Duplex Fuel Filters with the Engine Stopped

Note: The engine can auto start. Ensure that the power supply is isolated before any service or repair is performed.

Use the following procedures in order to remove air from the fuel system:

Illustration 1	g01627770
Typical example

• (A) The fuel flow is to the left-hand fuel filter.

• (B) The fuel flow is to both fuel filters.

• (C) The fuel flow is to the right-hand fuel filter.

Illustration 2	g01628110
Typical example

• (A) The fuel flow is to the left-hand fuel filter.

• (B) The fuel flow is to both fuel filters.

• (C) The fuel flow is to the right-hand fuel filter.

Commissioning procedure

Use the following procedure in order to remove air from both fuel filters.

Duplex Fuel Filters

1. The engine can auto start. Ensure that the power supply is isolated before any service or repair is performed.

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Illustration 3	g02164298
Typical example

2. Ensure that the fuel system is in working order. Check that the fuel supply valve (if equipped) is in the "ON" position.

3. Ensure that the control levers are in position B. Refer to illustration 1 and illustration 2.

4. Start the engine. Refer to Operation and Maintenance Manual, "Starting the Engine" for the correct procedure. The electric fuel priming pump will operate.

5. After the engine has started, operate the engine for a minimum of 5 minutes without load.

   Note: Operating the engine for this time period will help ensure that the fuel system is free of air.

6. Select the required position for the control levers on the secondary filters.

Priming a Duplex Fuel Filter with the Engine in Operation

Priming the Secondary Filters

1. Both the secondary fuel filter and the primary fuel filter (if equipped) must be replaced at the same time.

2. Slowly rotate the control lever on the secondary fuel filters toward position B.

Note: Position B will allow the flow of fuel to both filters.

3. Rotate the control lever to the required position.

4. Drain the tray below the filters.