Case 1526, 1530, 1537 Uni-Loader SkidSteer Service Manual

Table of Contents

1. General
2. Engines
3. Fuel System
4. Electrical
5. Power Train
6. Brakes
7. Hydraulics
8. Mounted Equipment

Manual Extract: Electrical Fuel Pump

The electrical fuel pump is designed with a solenoid which, when energized, causes the movement of a hollow plunger in a cylindrical bore. The plunger stroke i s controlled by a set of interrupter type contact points in the pump electrical circuit. The contact points function in a sealed section containing an inert gas for long point life.
Upon energization of the solenoid, the plunger i s forced down in the cylinder against the plunger spring which i s seated on a closed check valve in the bottom of the bore .. A check valve in the plunger opens permitting passage of the trapped fuel through the plunger.

On the opening of the contacts the solenoid i s de-energized; the plunger spring returns the plunger to the top of the bore at a fixed rate to provide the required pressure. During the upward movement of the plunger, the check valve in the plunger i s closed to move the fuel ahead of it into the fuel system and the check valve in the bottom of the bore i s open to permit passage of fuel into the cylinder for the next cycle.

A pulsation dampener in the top of the pump provides steady operation and even pressure. The pump also incorporates a pressure relief system to assure an immediate return to zero fuel pressure when the ignition i s turned off:
The filter system i s contained in the lower portion of the pump and consists of a filter and magnet.