Remove the fuel supply hose to the gear pump and install the manometer, Part Number ST-1111-3. Use the appropriate hose adapter for the specific engine being serviced.

If the gear pump inlet fitting has a Compuchek® fitting, the manometer can be installed there.

Hold the manometer at the same level as the gear pump connection.

Operate the engine at rated speed and no load.

Observe the reading on the manometer.

Fuel Inlet Restriction

Correct the restriction or replace the fuel filter.

NOTE: The cooling plate has about 25.4 mm Hg [1 in Hg] restriction.

Inspect the cooling plate for restriction, porosity, and leakage. To inspect for porosity and leakage, visually examine the cooling plate for fuel leaks. If any leaks are found, replace the cooling plate. Refer to Procedure 006-006 in Section 6.

Install the mercury manometer, Part Number ST-1111-3, line to a tee fitting. Connect one ON and OFF valve at either side of the tee. Attach the hose and appropriate fittings.

Remove the fuel line from the rear of the cooling plate (fuel in). Install one side of the manometer hose into the fuel line. Connect the line to the cooling plate. Connect the other side of the manometer hose into the line from the front of the cooling plate (fuel out). Make sure both valves are closed.

Start the engine and operate it at rated RPM and no load.

Open the valve on the inlet side of the manometer and read the vacuum on the manometer. Record the vacuum reading.

Close the valve on the inlet side of the manometer. Open the valve on the outlet side of the manometer. Record the vacuum reading on the manometer.

Cooling Plate Restriction

If the restriction is greater than the value given, clean or replace the cooling plate.