Starting Motor – Delco 50-MT Pinion Clearance – Adjust

When the solenoid is installed, make an adjustment of the pinion clearance. The adjustment should be made with the starting motor removed.

Illustration 1 g00716453

Connections for pinion clearance check

(4) Starting motor negative wire

1.Disconnect the starting motor negative wire (4) from the “G” ground terminal of the solenoid.

2.Connect the batteries to the solenoid per Illustration 1. The Illustration shows a 24 volt system with two 12 volt batteries that are connected in series to a starting motor. Connect four 8 volt batteries in series for a 32 volt system. Connect eight 8 volt batteries in series for a 64 volt system. Connect the positive side of the battery cable to the “S” terminal of the starting motor solenoid. Connect the negative side of the battery cable to the “G” terminal of the starting motor.

3.Temporarily, touch a wire from the “G” terminal to the “Mtr” terminal. The pinion will shift to the crank position and the pinion will stay there until the battery is disconnected.

Illustration 2 g00716455

Pinion clearance check

(1) Adjustment nut

(2) Pinion drive housing

(3) Pinion

(X) pinion clearance

4.Push the pinion toward the commutator in order to remove free movement.

5.Measure the clearance (X) from the pinion to the pinion drive housing. Pinion clearance (X) must be 9.10 ± 0.8 mm (0.36 ± 0.03 inch).

6.If the clearance is not correct, remove the plug on the shift lever housing (2). Turn the adjustment nut (1) until the clearance is correct. Turning the nut clockwise will decrease the clearance (X) .
Note: The plunger may turn when the adjustment nut (1) is being turned. If the plunger turns, disconnect the battery from the solenoid. Remove the solenoid from the starting motor. Hold the plunger from turning and adjust the nut (1). This procedure may need to be performed several times until the correct clearance is obtained.

7.Disconnect the batteries and install the plug into the shift lever housing.

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