General Testing Procedures

INJECTION PUMP





A worn or damaged plunger can affect the pressure and amount of fuel injected, thus reducing the power from the engine. Generally, if the pump is injecting fuel from one outlet, it will deliver from all outlets. The only exception to this would be a malfunctioning delivery valve.

GOVERNOR MALFUNCTIONS





Balance between the flyweight governor and control lever position controls the metering of the amount of fuel to be injected.

The pump governor performance and setting can affect engine power. Special equipment and qualified personnel are required to verify governor performance. If the seals are broken on the external adjustment screw, the fuel rate may be out of adjustment. The warranty of the pump and engine may be void If the seals have been tampered with or removed.

FUEL CONTROL LEVER TRAVEL AND ADJUSTMENT





The amount of fuel injected and subsequently the speed and power from the engine is controlled by the fuel control lever. Restricted travel of the lever can cause low power. Always check for full travel of the lever when diagnosing a low power complaint.

MANUAL SHUT DOWN LEVER





The Injection pump is equipped with a mechanical shut down lever. This lever Is spring-loaded in the run position. There is no cable or rod connected to the lever.

NOTE: Partial actuation of the mechanical shutdown lever will affect fuel flow and engine power.

ADVANCE TIMING MECHANISM





Regulated pressure produced by the vane supply pump in the injection pump is used to advance the timing. Timing advances as the engine speed increases. A return spring is used to retard the timing as the engine speed is reduced. If a spring should break, the timing will go to the advance position resulting In torque loss, a fuel knock and possible engine overheating.

Retarded (late) timing will result in torque loss, high fuel consumption and white to black smoke.

Replacement of the spring and repair of the advance timing mechanism must be performed by an authorized injection pump service center.

INJECTION PUMP TIMING





Pump-to-engine timing is extremely critical. Pump timing that is off by only a few crankshaft degrees will cause:

1. Poor performance - starting and power
2. Excessive smoke and emissions
3. Poor fuel economy