FINAL DRIVE GP 9W0594 - Caterpillar

When the governor moves toward FUEL OFF position, spring seat (4) and piston (2) move to the left. This movement pushes oil out of cylinder (1), through needle valve (5), and into oil reservoir (7). If the governor movement is slow, the oil provides no restriction to the movement of the piston and spring seat. If the governor movement is fast and the governor movement is in the FUEL OFF direction, the needle valve gives a restriction to the oil. The piston and the spring seat will move slowly. Automatic Timing Advance Unit
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Automatic timing advance unit (1) Weights (2) Springs (3) Slides (4) Dowels (5) Automatic timing advance unitThe automatic timing advance unit (5) is installed on the front of the fuel pump drive shaft. Weights (1) in the timing advance are driven by two slides (3). These slides (3) fit into notches that are made on an angle in the weights (1). The slides (3) are driven by two dowels (4) in the hub assembly of the gear assembly in automatic timing advance unit (5). When the centrifugal force (rotation) moves weights (1) outward against the force of springs (2), a movement of the notches in the weights occurs. This movement (1) causes slides (3) to change the angle between the timing advance gear and the two dowels (4) in the hub assembly. Since automatic timing advance unit (5) drives the fuel pump drive shaft, which is connected to the fuel injection pump camshaft, the fuel injection timing is also changed.Governor Control Group and the Regulation of Low Speed
Some engine applications use the engine in two ways:
As power for the mobile truck
As a stationary engineFor applications of these dual purpose engines, a control group is installed on the rear of the standard governor for stationary operation. The control group is not used when the truck is operating, but the control group can be engaged by air pressure for use as a stationary application. The governor control group sets the engine at 1600 rpm without any load. When the lever assembly is connected with the standard governor spring, the governor control group regulates engine speed within 5%. Operation
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Governor control group during normal operation (1) Spring (2) Piston assembly (3) Lever (4) Low speed governor springDuring normal operation, spring (1) holds piston assembly (2) forward far enough so that lever (3) does not contact low speed governor spring (4). This allows the normal operation of the governor.
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Governor control group during stationary operation (2) Piston assembly (3) Lever (4) Low speed governor spring (5) Governor control group (6) Adjusting screw (7) Governor spring When the engine is used as a stationary engine, air pressure engages governor control group (5). The air pressure affects two operations:
Air pressure moves piston assembly (2) to the rear.
Air pressure holds the piston assembly against adjusting screw (6) .The movement of the piston to the rear causes low speed governor spring (4) to contact lever (3). This moves governor spring (7)