Fuel Pump

This procedure presumes the fuel pump has been removed for inspection.
For fuel pressure testing,

Fuel Pump:

EXTERNAL INSPECTION
- Inspect the housing for cracks and other damage.
- Inspect the rocker arm for wear or damage.
- Replace the pump if defects are observed.

Inlet Valve Inspection:

INLET VALVE INSPECTION
- Pour a small amount of clean fuel into the inlet fitting.
- Move the rocker arm (1) toward the pump and hold it in that position.
- Block the return pipe (2) and the outlet pipe (3).
- Carefully push the rocker arm to the original position.
- There should be a marked increase in the amount of play after the arm is returned to the original position.
- Replace the fuel pump if results differ.

Outlet Valve Inspection:

OUTLET VALVE INSPECTION
- Pour a small amount of clean fuel into the inlet fitting.
- Block the inlet pipe (1).
- Move the rocker arm (2) to check for excessive play.

NOTE: Do not use excessive force to operate rocker arm.

- Replace the fuel pump if there is excessive play.

Diaphragm Inspection:

DIAPHRAGM INSPECTION
- Pour a small amount of clean fuel into the inlet fitting.
- Block the outlet pipe (1) and the return pipe (2).
- Using a regulated air supply, apply 29.4 kPa (4.3 psi) to inlet pipe (3).

NOTE: Excessive air pressure will rupture diaphragm.

- Air pressure should hold steady.
- Replace pump if results differ.

Oil Seal Inspection:

OIL SEAL INSPECTION
- Pour a small amount of clean fuel into the inlet fitting.
- Using a regulated air supply, apply 9.8 kPa (1.4 psi) to vent fitting (4).

NOTE: Excessive air pressure will rupture diaphragm.

- Air pressure should hold steady.
- Replace pump if results differ.