Tools Required

Notice: Do not clean the starter motor parts in a degreasing tank. Soaking parts will dissolve the permanent lubrication and may damage the electrical insulation. This will shorten starter motor life.

1. Clean all parts by wiping with a dry cloth.
2. Inspect the bushing or the armature bearing fit in the following locations:

•	The end frame

•	The shift lever housing

•	The drive end frame housing (If the bushings or the bearings are damaged, install new ones.)

3. Lubricate the bushings before assembling the starter motor.

•	Avoid over lubrication.

•	Do not lubricate the roller bearings, if equipped.

•	The roller bearings are permanently lubricated when manufactured.

4. Inspect the armature shaft for runout or scoring.

If the condition of the armature shaft is in doubt, install a new shaft.

5. Inspect the commutator for discolored or uneven conductors.

•	Do not turn the commutator on a lathe.

•	Do not undercut the insulation.

•	Clean the commutator with No. 240 grit emery cloth.

-	Blow away any copper dust.

-	If the commutator can not be cleaned satisfactorily, install a new armature.




6. Inspect the armature for short circuits using the following procedure:

•	Rotate the armature in a "growler."

•	Use a steel strip (such as a hacksaw blade) held on the armature, parallel to the shaft.

•	If a short circuit is detected, the steel strip will vibrate over the area.

•	Consult the "growler" manufacturer's instructions for more information.

•	Short circuits between the commutator bars can be produced by brush (carbon) dust or copper dust.




7. Inspect the armature for opens as follows:

•	Look for loose connections where the conductors join the commutator bars.

•	Poor connections cause arcing.

•	Arcing causes burning of the commutator.

8. Inspect the armature for grounds with a self-powered test lamp (continuity tester). Use J 21008-A .

•	Place one test probe on the commutator.

•	Place the other test probe on the armature core or shaft.

•	If the test lamp lights, the armature is grounded.

9. Inspect the brushes for wear.

•	If the brushes are worn to half the size of a new brush, install new brushes.

10. Inspect the holders for dirt or damage.

Make sure that the brushes move freely and do not bind in the holders.

11. Inspect the brush springs for distortion or discoloring (indicating they have lost their tension).
12. Repair or replace as necessary.
13. Inspect the field coils.

•	Look for burned or damaged insulation.

•	Look for damaged connections.

•	Look for loose poles.

•	If the condition of the coils is doubtful, replace the field and frame assembly.




14. Inspect the field coils for grounds.

•	Connect the two leads from the "growler" between the field frame and the field connector.

•	Be sure that the brush ends do not contact the field frame.

•	If the test lamp lights, the field coils are grounded.

•	Install a new field and frame assembly.




15. Inspect the field coils for opens.

•	Connect the two leads from the "growler" between the field connector and each of the positive brushes.

•	If the test lamp does not light at both brushes, then the fields are open.

16. Inspect the field coils for shorts.

•	Shorts are indicated if the starter motor runs poorly after all other inspection procedures have been completed.

•	The frame and field coils must be replaced as an assembly, if they are found to be shorted.

17. Inspect the drive assembly (clutch) by turning the drive pinion in the cranking direction.

•	If the drive pinion turns roughly in the cranking direction, replace the complete overrunning clutch assembly.

•	If the drive pinion slips in the cranking direction, replace the complete overrunning clutch assembly.




18. Inspect the solenoid for grounds using a self-powered test lamp J 21008-A .
19. If the solenoid does not pass the following tests, install a new solenoid.

19.1.

Connect J 21008-A between the BAT terminal and the metal housing (ground).

19.2.

The lamp should not light, meaning that the terminal is not grounded.

19.3.

Connect J 21008-A between the (S) terminal and the metal housing.

The lamp should light.

19.4.

Connect J 21008-A between the (M) terminal and the (S) terminal, or connect the test lamp between the (M) terminal and the metal housing.

The lamp should light.

Notice: To prevent overheating of the solenoid pull-in winding, do not leave the winding energized for more than 15 seconds. The current draw will decrease as the winding temperature increases.




20. Inspect the hold-in winding and the pull-in winding.

Important: Before testing, the solenoid must be removed from the starter motor, or the field lead must be removed from the terminal on the solenoid.

21. In order to test both windings, perform the following procedure:

21.1.

Connect an ammeter in series with a 12 V battery positive terminal, and the switch (S) terminal on the starter solenoid.

21.2.

Connect a digital multimeter J 39200 to the (S) terminal on the starter solenoid and to the negative battery terminal.

21.3.

Connect the carbon pile (variable resistance) across the battery.

21.4.

Ground the solenoid motor (M) terminal.

21.5.

Adjust the voltage to 10 V and observe the ammeter reading.

21.6.

The reading should be between 60-85 amperes.

•	A higher ammeter reading means that the winding is shorted or grounded.

•	A lower ammeter reading means that there is excessive resistance in the winding.

21.7.

The winding resistance can be read directly. This is done with a digital multimeter J 39200 which measures in tenths of an ohm.

21.8.

Coil resistance is determined by dividing the voltage by the amperes (voltage/amperes). Refer to Starter Motor Usage .