Starter Motor: Testing and Inspection
CHECKING FOR OPERATIONMagnetic Switch Pull-In Test:
MAGNETIC SWITCH PULL-IN TEST
1. Disconnect 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:
MAGNETIC SWITCH HOLD-IN TEST
1. Disconnect 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. Draw out the pinion to the pinion stopper by hand.
4. If pinion remains out, everything is operating properly. If pinion moves in, hold-in circuit is open. Replace the magnetic switch.
Free Running Test:
FREE RUNNING TEST
1. Place the starter motor in a vise equipped with soft jaws and connect a fully-charged 12-volt battery to starter motor as follows:
2. Connect a test ammeter (100 - ampere scale) and carbon pile rheostat in series between the battery positive post and starter motor terminal.
3. Connect a voltmeter (15 - volt scale) across the 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 11 V.
7. Confirm that the maximum amperage is within the specifications and that the starter motor turns smoothly and freely.
Standard value: 90 A or less
Magnetic Switch Return Test:
MAGNETIC SWITCH RETURN TEST
1. Disconnect 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 operating properly. If it doesn't, replace magnetic switch.
CAUTION: Be careful not to pinch your finger when drawing out the pinion.
INSPECTION
COMMUTATOR CHECK
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 (0.004 in.)
Commutator:
2. Check the outer diameter of the commutator.
Standard value: 29.4 mm (1.158 in.)
Limit: 28.4 mm (1.118 in.)
Commutator:
3. Check the depth of the undercut between segments.
Standard value: 0.5 mm (0.020 in.)
Brush Holder:
BRUSH HOLDER CHECK
Check for continuity between the brush holder plate and the
brush holder.
The normal condition is non-continuity.
Brushes And Springs Replacement:
BRUSH CHECK
1. Brushes that are worn beyond wear limit line, or oil-soaked, should be replaced.
2. When replacing ground brush, slide the brush from brush holder by prying retaining spring back.
OVERRUNNING CLUTCH CHECK
1. While holding clutch housing, rotate the pinion. Drive pinion should rotate smoothly in one direction, but should not rotate in opposite direction. If clutch does not function properly, replace overrunning clutch assembly.
2. Inspect pinion for wear or burrs. If pinion is worn or burred, replace overrunning clutch assembly. It pinion is damaged, also inspect ring gear for wear or burrs.
FRONT AND REAR BRACKET BUSHING CHECK
Inspect bushing for wear or burrs. It bushing is worn or burred, replace front bracket assembly or rear bracket assembly.
ARMATURE CHECK
Armature Short Circuit Test:
1. Check that the armature coil is not shorted.
2. Place armature in a growler.
3. Hold a thin steel blade parallel and just above while rotating armature slowly in growler. A shorted armature will cause blade to vibrate and be attracted to the core. Replace shorted armature.
Armature Coil Grounding Test:
4. 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:
5. Check for continuity between segments. The condition is normal if there is continuity.