Inspect the brush cover for discoloration, indication the starter has been overheated.
Inspect the pinion teeth for wear and damage.
Armature Short-Circuit Test: Use a growler tester, put the armature on the growler and hold a hack saw blade against the armature core while slowly rotating the armature [Figure 60-40-25]. A short circuited armature causes the blade to vibrate and be attracted to the core. An armature which is short-circuited must be replaced.
Armature Winding Ground Test: Use a circuit tester, touch one probe to a commutator segment and the other probe to the armature core [Figure 60-40-26]. There should be no continuity. If there is continuity, the armature is grounded and must be replaced.
Armature Winding Continuity Test: Use a circuit tester, touch the probes to two commutator segments [Figure 60-40-27]. There should be continuity at any point. If there is no continuity, the winding is open-circuited, replace the armature.
Commutator Run-Out Test: check the commutator run-out as shown in [Figure 60-40-28].
Service Limit – 0.020 inch (0,4 mm)
If the commutator exceeds the service limit, repair as needed.
Measure the segment mica depth (Item 1) [Figure 60-40-29].
Service Limit – 0.008 inch (0,2 mm)
If it is worn, replace the armature.
Check the commutator surface for burned spots which usually indicates an open-circuit, and correct it using #400 sand paper.
Check the field windings for wear and damage.
Check all the connections for clean and tight solder joints.
Field Winding Ground Test: Use a circuit tester, touch one probe to the field winding end of the brush and the other probe to the surface of the frame [Figure 60-40-30]. There should be no continuity. If there is continuity, the field windings are grounded.
Replace the frame.
Field Windings Continuity Test: Use a circuit tester, touch one probe to the wire and the other probe to the brush [Figure 60-40-31]. There should be continuity. If there is no continuity, the field windings are open-circuited.
Replace the frame.
Inspect the brushes for wear and damage.
Replace the brush holder and yoke if the brushes need replacement.
Check brush spring, for damage or rust. Replace as needed.
Brush Holder Insulation Test: Use a circuit tester, touch one probe to the positive brush holder plate and the other probe to the holder plate [Figure 60-40-32]. There should be no continuity. If there is continuity, replace or repair.
NOTE: Assemble the over running clutch, pinion shaft, springs, and pinion for this test.
Inspect the pinion, it must rotate freely in the direction of the starter rotation and lock in the opposite rotation.
Pull the pinion out (to the engaged position) [Figure 60-40-33] and allow it to snap back to the retracted position. The pinion must fully return to the retracted position.
The following tests should be done without the armature assembly. Install the magnetic switch in the switch housing.
NOTE: Each test should be performed a short time (3 to 5 seconds) to prevent the magnetic switch winding from burning. Each test should be performed with 12 volts.
Pull-In Test: Connect the wires as shown in [Figure 60-40-34]. When connecting Terminal C and M.T. are closed, the pinion should engage.
Hold-In Test: With the same conditions as in the pull-in test, open the connecting Terminal C [Figure 60-40-35]. The pinion should remain in the engaged position.
Return Test: With the same conditions as in the hold-in test, open the connecting Terminal 50 [Figure 60-40-36]. The pinion should return immediately.
