Starter Motor: Testing and Inspection
INSPECTION1. INSPECT STARTER ARMATURE ASSEMBLY
a. Measure the resistance.
1. Measure the resistance between the segments of the commutator.
Standard resistance: Below 1 Ohm
If the result is not as specified, replace the starter armature assembly.
2. Measure the resistance between a segment of the commutator and armature coil core.
Standard resistance: 10 kOhms or higher
If the result is not as specified, replace the armature assembly.
b. Inspect circle runout.
1. Place the armature on V-blocks.
2. Using a dial gauge, measure the circle runout.
Maximum circle runout: 0.05 mm (0.0020 in.)
If the circle runout is greater than the maximum, correct it on a lathe.
c. Using a vernier caliper, measure the commutator diameter.
Standard undercut depth: 35.0 mm (1.378 in.)
Minimum undercut depth: 34.0 mm (1.339 in.)
If the diameter is less than the minimum, replace the armature assembly.
d. Measure the undercut depth of the commutator.
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 the minimum, correct it with a hacksaw blade.
e. Inspect the bearings.
1. Check that the bearing rotate smoothly.
If the diameter is less than the minimum, replace the armature assembly.
2. INSPECT STARTER YOKE ASSEMBLY
a. Inspect the field coil for an open circuit.
1. Measure the resistance between the lead wire and field coil brush lead.
Standard resistance: Below 1 Ohm
If the result is not as specified, replace the starter yoke assembly.
b. Inspect the shunt coil for an open circuit.
1. Measure the resistance between the shunt coil terminals.
Standard resistance: 1.5 to 1.9 Ohms at 20 degrees C (68 degrees F)
If the result is not as specified, replace the starter yoke assembly.
3. INSPECT BRUSH
a. Using a vernier caliper, 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 the minimum, replace the starter brush holder assembly and starter yoke assembly.
4. INSPECT STARTER BRUSH HOLDER ASSEMBLY
a. Inspect the brush insulation.
1. Using an ohmmeter, measure the resistance between the positive and negative brush holders.
Standard resistance: 10 kOhms or higher
If the result is not as specified, replace the brush holder assembly.
b. Take the pull scale reading the instant the brush spring separates from the brush.
Standard spring installed load: 21.5 to 27.5 N (2.2 to 2.8 kgf.cm, 4.8 to 6.2 in.lbf)
Minimum spring installed load: 12.7 (1.3 kgf.cm, 2.9 in.lbf)
If the spring load is less than the minimum, replace the brush spring.
5. INSPECT STARTER CLUTCH SUB-ASSEMBLY
a. 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.
6. INSPECT MAGNET STARTER SWITCH ASSEMBLY
a. Check if the pull-in coil has an open circuit.
1. Measure the resistance between terminals 50 and C.
Standard resistance: Below 2 Ohms
If the result is not as specified, replace the magnet starter switch assembly.
b. Check if the hold-in coil has an open circuit.
1. Measure the resistance between terminal 50 and the switch body.
Standard resistance: Below 1 Ohm
If the result is not as specified, replace the magnet starter switch assembly.