Starter Motor: Testing and Inspection
INSPECTION1. ARMATURE
1. Check the commutator for any sign of burns of rough surfaces or stepped wear. If it has minor wear, correct it by using sand paper (#300).
2. Run-out test
Check the commutator for run-out, and then replace if it exceeds the limit.
3. Armature short-circuit test
Check the armature for short circuit by placing it on growler tester. Hold an iron sheet (thickness gauge, etc.) against the armature core while slowly rotating the 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.
4. Armature discontinuity test
Using a circuit tester, touch one probe to the Armature and the other to commutator. No continuity is normal. If there is continuity, the armature is grounded.
Replace the armature if it is grounded.
2. OVERRUNNING CLUTCH
Inspect the teeth of pinion for wear and damage. Replace if it is damaged. Rotate the pinion in the right direction of rotation (counterclockwise). It should rotate smoothly. But in the opposite direction, it should be locked.
CAUTION: Do not clean the overrunning clutch with oil to prevent grease from flowing out.
3. 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 holder discontinuity test
Using a circuit tester, bring one probe into contact with positive side brush holder and the other with negative side brush holder.
No continuity is normal.
4. SWITCH ASSEMBLY
1. Return spring check
Make sure the plunger returns to its original position immediately after pressed-in then released.
2. Magnet switch continuity test
Be sure there is continuity between the terminals S and M, and between terminal S and ground. Use a circuit tester.
Also check to be sure there is no continuity between terminal M and B.
5. FRONT BEARING
Check the front bearing to make sure there are no damage or rust.
Also, insert the shaft into front bearing to make sure the front bearing rotates smoothly when the shaft is rotated.
Replace the front bearing if faulty.
6. SHOCK ABSORBER BEARING CLEARANCE
Measure the outside (A) diameter of sliding part for shaft shock absorber bearing.
Then, measure the inside (B) diameter of shock absorber bearing, and calculate the clearance.
If it exceeds the service limit, replace the oilless bearing or shaft.
7. REAR BEARING
Check the rear bearing, and replace the rear bearing if there are damage, lock or rust.
8. PLANETARY GEAR BUSHING
Measure the outer diameter (A) of pin which is press-fitted into shaft.
Then, measure the inner diameter (B) of planetary gear bushing, and calculate the clearance.
If it exceeds the service limit, replace the planetary gear or shaft.
9. SWITCH ASSEMBLY OPERATION
NOTE: Test period of each test must be within short time (3-5 seconds).
1. Vacuum test
Disconnect the harness from terminal M and connect it as shown in the figure. Make sure the pinion gear sticks out.
2. Hold test
Make sure the pinion gear remains stick out evenafter disconnecting terminal M in the above condition.
3. Return test
Connect the positive terminal to terminal S and the negative terminal to terminal M and starter body to pull the pinion gear at the main contact point. Make sure the pinion gear returns to its original position when the terminal S is disconnected.
10. 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 in figure.
1. No-load test
With switch on, adjust the variable resistance until the voltage is 11 V, read the value of ammeter to measure rotating speed. Compare these values with the standard.
No-load test (standard):
Voltage/Current
Max. 11 V / 90 A or less
Rotating speed
More than 1,720 rpm
2. Load test
Apply the specified braking torque to starter. The condition is satisfactory if the current draw and rotating speed are within specifications.
Load test (standard):
Voltage/Load
8 V / 12.78 N.m (1.30 kgf.m, 9.4 ft.lb)
Current/Speed
370 A/850 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 standard voltage.
Lock test (standard):
Voltage/Current
3 V/900 A or less
Torque
15.42 N.m (1.57 kgf.m, 11.3 ft.lb)