Cruise Control Servo: Adjustments

Fig. 90 Lock In Screw Adjustment. RWD:

The lock in screw adjustment controls the accuracy of the speed control unit. When the Set button is depressed and released at speeds above 30 mph, the speed control system locks in and should hold vehicle at same speed at which it is traveling. Lock in accuracy will be affected by the following:
1. Poor engine performance.
2. Power to weight ratio (as in pulling a trailer).
3. Improper slack in throttle control cable.
Need for adjustment can be determined only after accurate diagnosis of the speed control system operation.
If speed drops more than 2 to 3 mph, the lock in adjusting screw should be turned counterclockwise to correct. Turning the lock in adjusting screw 1/4 turn adjust the lock in accuracy about 1 mph. If speed increases more than 2 to 3 mph, the lock in adjusting screw should be turned clockwise to correct.
If the lock in adjusting screw is loose replace the servo. This adjustment must not exceed two turns in either direction or damage to unit may occur.