Fuel pump timing adjustment in marine two stroke engine

The fuel injection timing depends on the fuel pump lead.

Before adjusting the lead. Isolate the fuel oil system by closing inlet and return valves.

Check if the roller is resting on the base circle of the cam.

Measure the distance between upper edge of roller guide housing and top of thrust piece, using a depth gauge.

Compare the reading with the prescribed valve in the manufacturer's manual.

To adjust the fuel pump lead. Remove the thrust piece using a special extraction tool.

Add shims of required thickness to advance or remove them to retard the timing.

Use a mallet to mount the thrust piece in the slot. Measure the load once again.

Run the engine on full load and check the combustion pressure.