Starter Motor: Testing and Inspection
Fig. 5 Testing Magnetic Switch:
INSPECTION
MAGNETIC SWITCH PULL-IN TEST
1. Disconnect field coil wire from M-terminal of magnetic switch.
2. Connect a 12V battery between S-terminal and M-terminal.
CAUTION: This test must be performed quickly (in less than 10 seconds) to prevent coil from burning.
3. If pinion moves out, then pull-in coil is good. If it doesn't, replace magnetic switch.
MAGNETIC SWITCH HOLD-IN TEST
1. Disconnect field coil wire from M-terminal of magnetic switch.
2. Connect a 12V battery between S-terminal and body.
CAUTION: This test must be performed quickly (in less than 10 seconds) to prevent coil from burning.
3. If pinion remains out, everything is in order. If pinion moves in, hold-in circuit is open. Replace magnetic switch.
Free Running Test:
FREE RUNNING TEST
1. Place starter motor in a vise equipped with soft jaws and connect a fully-charged 12-volts battery to starter motor as follows:
2. Connect a test ammeter (130-ampere scale) and carbon pile rheostat in series between battery positive post and starter motor terminal.
3. Connect a voltmeter (15-volts scale) across starter motor.
4. Rotate carbon pile to full-resistance position.
5. Connect battery cable from battery negative post to starter motor body.
6. Adjust the rheostat until the battery voltage shown by the voltmeter is 11V.
7. Confirm that the maximum amperage is within the specifications and that the starter motor turns smoothly and freely.
Current: Max. 110 Amps
MAGNETIC SWITCH RETURN TEST
1. Disconnect field coil wire from M-terminal of magnetic switch.
2. Connect a 12V battery between M-terminal and body.
CAUTION: This test must be performed quickly (in less than 10 seconds) to prevent coil from burning.
3. Pull pinion out and release. If pinion quickly returns to its original position everything is in order. If it doesn't, replace magnetic switch.
CAUTION: Be careful not to pinch your finger when drawing out the pinion.
COMMUTATOR
Commutator:
1. Place the armature on a pair of V-blocks, and check the deflection by using a dial gauge.
Standard value: 0.05 mm (0.0020 in.)
Limit: 0.1 mm (0.0040 in.)
Commutator:
2. Check the outer diameter of the commutator.
Standard value: 32.3 mm (1.27 in.)
Limit: 31.2 mm (1.22 in.)
Commutator:
3. Check the depth of the undercut between segments.
Standard value: 0.5 mm (0.020 in.)
Brush Holder:
BRUSH HOLDER
Check for continuity between the brush holder plate and the brush holder.
The normal condition is non-continuity.
OVERRUNNING CLUTCH
1. While holding clutch housing, rotate the pinion. The drive pinion should rotate smoothly in one direction, but should not rotate in the opposite direction. If the clutch does not function properly, replace the overrunning clutch assembly.
2. Inspect pinion for wear or burrs. If the pinion is worn or burred, replace the overrunning clutch assembly. If the pinion is damaged, also inspect the ring gear for wear or burrs.
FRONT AND REAR BRACKET BUSHING
Inspect bushings for wear or burrs. If bushings are worn or burred, replace the front or rear bracket assembly.
ARMATURE TEST
Armature Short Circuit Test:
ARMATURE SHORT-CIRCUIT TEST
1. Place the armature in a growler.
2. Hold a thin steel blade parallel and just above while rotating the armature slowly in growler. A shorted armature will cause the blade to vibrate and be attracted to the core. Replace a shorted armature.
Armature Coil Grounding Test:
ARMATURE COIL GROUND TEST
Check the insulation between the armature coil cores and the commutator segments. They are normal if there is no continuity.
Armature Coil Open Circuit Inspection:
ARMATURE COIL OPEN-CIRCUIT TEST
Check for continuity between segments. The condition is normal if there is continuity.