Starter Motor: Testing and Inspection
INSPECTION1. INSPECT STARTER ASSEMBLY
CAUTION: These tests must be performed within 3 to 5 seconds to prevent the coil from burning out.
a. Perform pull-in/holding test.
1. Remove the nut and disconnect the lead wire from terminal C.
2. Connect the battery to the magnetic stater switch as shown in the illustration. Then check that the clutch pinion gear moves outward.
3. With the battery connected as above and the clutch pinion gear out, disconnect the negative (-) lead from terminal C. Check that the pinion gear remains out.
4. Disconnect the negative (-) lead from the starter body. Check that the clutch pinion gear returns inward.
If the result is not as specified, replace the starter assembly.
b. Perform operation test without load.
1. Connect the lead wire to terminal C with the nut.
Torque: 5.9 N.m (60 kgf.cm, 52 in.lbf)
2. Mount the starter in a vise.
3. Connect the battery and ammeter to the starter as shown in the illustration.
4. Check that the starter rotates smoothly and steadily while the pinion gear is moving outward. Then measure the current.
Specified current: 100 A or less at 11.5 V
If the result is not as specified, replace the starter assembly.
2. INSPECT STARTER ARMATURE ASSEMBLY
a. Inspect the commutator surface for contamination and burns.
If the surface is dirty or burnt, correct it with sandpaper (#400) or a lathe.
b. Inspect the commutator an open circuit.
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.
c. Inspect the commutator to check if it is not grounded.
1. Measure the resistance between the commutator and armature coil core.
Standard resistance: 10 k ohms or higher
If the result is not as specified, replace the starter armature assembly.
d. Inspect the commutator circle runout.
1. Place the armature on V-blocks.
2. Using a dial indicator, measure the commutator's runout.
Maximum commutator's runout: 0.05 mm (0.002 in.)
If the circle runout is greater than the maximum, correct it with sandpaper (#400) or replace the starter armature assembly.
e. Using a vernier caliper, 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 the minimum, replace the starter armature assembly.
f. Measure the undercut depth of the commutator.
Standard depth: 0.7 mm (0.028 in.)
Minimum depth: 0.2 mm (0.008 in.)
If the undercut depth is less than the minimum, increase the depth using a hacksaw blade.
g. Inspect the starter armature bearing.
1. Check that the bearing is not rough or worn.
OK: The bearing rotates smoothly.
If the bearing does not rotate smoothly, replace the starter armature assembly.
3. INSPECT STARTER YOKE ASSEMBLY
a. Inspect the resistance of the field coil.
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 resistance.
1. Measure the resistance between the shunt oil terminals.
Standard resistance: 1.5 to 1.9 ohms at 20 °C (68 °F)
If the result is not as specified, replace the starter yoke assembly.
4. INSPECT BRUSH
a. Using a vernier caliper, measure the brush length.
Standard brush length: 15.0 mm (0.591 in.)
Minimum brush length: 9.0 mm (0.354 in.)
If the brush length is less than the minimum, replace the brush holder and yoke assembly.
5. INSPECT STARTER BRUSH HOLDER ASSEMBLY
a. Check the resistance between the positive (+) and negative (-) brush holders.
Standard resistance: 10 k ohms or higher
If the result is not as specified, repair or replace the starter brush holder assembly.
b. Inspect the load of the brush spring.
1. Take the pull scale reading immediately after the brush spring separates from the brush.
Standard spring load: 21.5 to 27.5 N (2.2 to 2.8 kgf, 4.9 to 6.2 lbf)
Minimum spring load: 12.7 N (1.3 kgf, 2.9 lbf)
If the spring load is less than the minimum, replace the brush springs.
6. INSPECT STARTER CLUTCH SUB-ASSEMBLY
a. Inspect the starter clutch to check that it can rotate clockwise, but cannot rotate counterclockwise.
If the starter clutch does not operate as specified, replace the starter clutch sub-assembly.
7. INSPECT MAGNET STARTER SWITCH ASSEMBLY
a. Inspect the resistance of the pull-in coil.
1. Measure the resistance between terminals 50 and C.
Standard resistance: Below 1 ohm
If the resistance is not as specified, replace the magnet starter switch assembly.
b. Inspect the resistance of the hold-in coil.
1. Measure the resistance between terminal 50 and the switch body.
Standard resistance: Below 2 ohms
If the resistance is not as specified, replace the magnet starter switch assembly.