Starter Motor: Testing and Inspection

INSPECTION




1. INSPECT COMMUTATOR FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between the segments of the commutator.
If there is no continuity between any segment, replace the armature.




2. INSPECT COMMUTATOR FOR GROUND
Using an ohmmeter, check that there is no continuity between the commutator and armature coil core.
If there is continuity, replace the armature.

3. INSPECT COMMUTATOR FOR DIRTY AND BURNT SURFACE
If the surface is dirty or burnt, correct it with sandpaper (No.400) or on a lathe.




4. INSPECT COMMUTATOR CIRCLE RUNOUT
a. Place the commutator on V-blocks.
b. Using a dial indicator the circle runout.
Maximum circle runout: 0.05 mm (0.0020 in.)
If the circle runout is greater than maximum, correct it on a lathe.




5. INSPECT COMMUTATOR DIAMETER
Using vernier calipers, measure the commutator diameter.
Standard diameter: 35.0 mm (1.378 in.)
Minimum diameter: 34.0 mm (1.339 in.)
If the diameter is less than minimum, replace the armature.




6. INSPECT UNDERCUT DEPTH
Check that the undercut depth is clean and free of foreign materials.
Smooth out the edge.
Standard undercut depth: 0.7 mm (0.028 in.)
Minimum undercut depth: 0.2 mm (0.008 in.)
If the undercut depth is less than minimum, correct it with a hacksaw blade.




7. INSPECT FIELD COIL FOR OPEN CIRCUIT
Using an ohmmeter, check that there is continuity between the lead wire and field coil brush lead.
If there is no continuity, replace the field frame.




8. INSPECT SHUNT COIL FOR OPEN CIRCUIT
Using an ohmmeter, measure the resistance between shunt coil terminals (A) and (B).
Resistance: 1.5 - 1.9 ohms at 20 °C (68 °F)
If the resistance is not as specified, replace the field frame.




9. INSPECT BRUSH LENGTH
Using vernier calipers, measure the brush length.
Standard length: 15.0 mm (0.591 in.)
Minimum length: 9.0 mm (0.354 in.)
If the length is less than minimum, replace the brush holder and field frame.




10. INSPECT BRUSH SPRING LOAD
Take the pull scale reading the instant the brush spring separates from the brush.
Standard spring installed load: 21.5 - 27.5 N (2.2 - 2.8 kgf, 4.8 - 6.2 lbf)
Minimum spring installed load: 12.7 N (1.3 kgf, 2.9 lbf)
If the installed load is less than minimum, replace the brush springs.




11. INSPECT BRUSH HOLDER INSULATION
Using an ohmmeter, check that there is no continuity between the positive (+) and negative (-) brush holders.
If there is continuity, repair or replace the brush holder.

12. INSPECT GEAR TEETH
Check the gear teeth on the pinion gear, idle gear and the clutch assembly for wear or damage.
If damaged, replace the gear or clutch assembly.
If damaged, also check the drive plate ring gear for wear or damage.




13. INSPECT CLUTCH PINION GEAR
Rotate the pinion gear clockwise, and check that it turns freely.
Try to rotate the pinion gear counterclockwise and check that it locks.
If necessary, replace the clutch assembly.

14. INSPECT REAR BEARING
Turn the bearing by hand while applying inward force.
If resistance is felt or the bearing sticks, replace the bearing.

15. INSPECT FRONT BEARING
Turn the bearing by hand while applying inward force.
If resistance is felt or the bearing sticks, replace the bearing.




16. DO PULL-IN COIL OPEN CIRCUIT TEST
Using an ohmmeter, check that there is continuity between terminals 50 and C.
If there is no continuity, check and replace the magnetic switch.




17. DO HOLD-IN COIL OPEN CIRCUIT TEST
Using an ohmmeter, check that there is continuity between terminal 50 and the switch body.
If there is no continuity, replace the magnetic switch.

TEST

NOTE: These tests must be done within 3 to 5 seconds to avoid burning out the coil.




1. DO PULL-IN TEST
a. Disconnect the field coil lead wire from terminal C.
b. Connect the battery to the magnetic switch. Check that the pinion gear moves outward.




2. DO HOLD-IN TEST
While connected as above with the pinion gear out, disconnect the negative (-) lead from terminal C. Check that the pinion gear remains out.




3. INSPECT CLUTCH PINION GEAR RETURN
Disconnect the negative (-) lead from the starter body. Check that the pinion gear returns inward.




4. DO NO-LOAD PERFORMANCE TEST
a. Connect the battery and ammeter to the starter.
b. Check that the starter rotates smoothly and steadily with the pinion gear moving out. Check that the ammeter shows the specified current.
Specified current: At 11.5 V: 100 A or less