Starter Motor: Testing and Inspection
INSPECTION1. ARMATURE
1. Check the commutator for any sign of burns of rough surfaces or stepped wear. If wear is of a minor nature, correct it by using sand paper.
2. Run-out test
Check the commutator run-out, and then replace if it exceeds the limit.
3. Depth of segment mold
Check the depth of segment mold.
4. Armature short-circuit test Check the armature for short-circuit by placing it on growler tester. Hold a iron sheet against the armature core while slowly rotating armature. A short-circuited armature will cause the iron sheet to vibrate and to be attracted to core. If the iron sheet is attracted or vibrates, the armature, which is short-circuited, must be replaced or repaired.
5. Armature ground test
Using a circuit tester, touch one probe to the commutator segment and the other to shaft. There should be no continuity. If there is continuity, the armature is grounded. Replace the armature if it is grounded.
2. YOKE
Make sure the pole is set in position.
3. OVERRUNNING CLUTCH
Inspect the teeth of pinion for wear and damage. Replace if it is damaged. Rotate the pinion in direction of rotation (counterclockwise). It should rotate smoothly. But in opposite direction, it should be locked.
CAUTION: Do not clean the overrunning clutch with oil to prevent grease from flowing out.
4. BRUSH AND BRUSH HOLDER
1. Brush length
Measure the brush length, and then replace if it exceeds the service limit.
Replace if abnormal wear or cracks are noticed.
2. Brush movement
Be sure the brush moves smoothly inside brush holder.
3. Brush spring force
Measure the brush spring force with a spring scale.
If it is less than the service limit, replace the brush holder.
Brush spring force:
Standard
15.9 - 19.5 N (1.62 - 1.99 kgf, 3.57 - 4.38 lb) (when new)
Service limit
2.5 N (0.25 kgf, 0.56 lb)
5. SWITCH ASSEMBLY
Be sure there is continuity between the terminals S and M, and between terminal S and ground. Use a circuit tester (set in "ohm").
Also check to be sure there is no continuity between terminal M and B.
6. SWITCH ASSEMBLY OPERATION
1. Connect the terminal S of switch assembly to positive terminal of battery with a lead wire, and starter body to ground terminal of battery. The pinion should be forced endwise on shaft.
CAUTION: With the pinion forced endwise on shaft, starter motor can sometimes rotate because current flows, through pull-in coil, to motor. This is not a problem.
2. Disconnect the connector from terminal M, and then connect the positive terminal of battery and terminal M using a lead wire and ground terminal to starter body.
In this test set up, the pinion should return to its original position even when it is pulled out with a screwdriver.
7. PINION GAP
1. Measure the pinion gap while the pinion is pulled out as shown in the figure.
If the motor is running with the pinion forced endwise on shaft, disconnect the connector from terminal M of switch assembly, and then connect terminal M to ground terminal (-) of battery with a lead wire. Next, gently push the pinion back with your fingertips, and then measure the pinion gap.
2. If the pinion gap is outside specified range, remove or add number of adjustment washers used on the mounting surface of switch assembly until correct pinion gap is obtained.
8. PERFORMANCE TEST
The starter should be submitted to performance tests whenever it has been overhauled, to assure its satisfactory performance when installed on the engine.
Three performance tests, no-load test, load test, and lock test, are presented here; however, if the load test and lock test cannot be performed, carry out at least the no-load test.
For these performance tests, use the circuit shown.
1. No-load test
With switch on, adjust the variable resistance to obtain 11 V, take the ammeter reading, and then measure the starter speed. Compare these values with the specifications.
No-load test (Standard):
Voltage/Current
MT vehicles
MAX. 11 V/95 A
AT vehicles
MAX. 11 V/90 A
Rotating speed
MT vehicles
2,500 rpm or more
AT vehicles
2,000 rpm or more
2. Load test
Apply the specified braking torque to starter. The condition is satisfactory if the current draw and starter speed are within the specifications.
Load test (Standard):
Voltage/Load
MT vehicles
7.5 V/8.84 N (0.90 kgf, 1.99 lb)
AT vehicles
7.7 V/16.7 N (1.70 kgf, 3.75 lb)
current speed
MT vehicles
300 A/870 rpm or more
AT vehicles
400 A/710 rpm or more
3. Lock test
With the starter stalled, or not rotating, measure the torque developed and current draw when the voltage is adjusted to the specified voltage.
Lock test (Standard):
Voltage/Current
MT vehicles
4 V/680 A or less
AT vehicles
3.5 V/960 A or less
Torque
MT vehicles
17.0 N (1.73 kgf, 3.82 lb) or more
AT vehicles
31.0 N (3.16 kgf, 6.97 lb) or more