MUFFLER AS 7W5867 - 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 is replaced.
A new injection pump is installed.Use the following procedure in order to remove air from the fuel system:
Ensure that all fuel connections are installed correctly.
Turn the keyswitch to the RUN position. Leave the keyswitch in the RUN position for three minutes. If a manual purging screw is installed, slacken the manual purging screw during priming the fuel system.
Crank the engine with the throttle lever in the closed position until the engine starts.
Illustration 1 g01228000
Injector nuts
Note: If necessary, loosen the union nuts (1) on the fuel injection lines at the connection with the fuel injector until fuel is evident. Stop cranking the engine. Tighten the union nuts to a torque of 27 N m (20 lb ft).
Start the engine and run the engine at idle for one minute.
Cycle the throttle lever from the low idle position to the high idle position three times. The cycle time for the throttle lever is approximately one second to six seconds for one complete cycle. Note: In order to purge air from the fuel injection pump on Caterpillar engines with a fixed throttle, the engine should be run at full load for thirty seconds. This should be repeated three times. This will assist in removing trapped air from the fuel injection pump.
Return the engine to no load condition. Check for leaks in the fuel system.