1. Starting Systems
State a major safety precaution when removing or working around a starting motor

6. Don’t make your starter an Arc Welder!
Always unhook the battery ground
Before removing the starter motor

7. Starting Systems Identify the following components Armature Commutator
Brushes
Pole Shoe
Field Coil

8. Starter Armatures

9. The Armature is a rotating electromagnet

10. Commutator bars allow current in and out of the armature

11. Brushes ride on commutator bars
Brushes transfer electrons from the stationary field coils to the spinning armature

12. Insulated Brushes
Grounded Brushes

13. Field Coils are Stationary Electromagnets
Pole Shoes concentrate the stationary magnetic field

14. Starting Systems Identify the following components
Starter housing or frame
Bushings
Starter Drive Pinion
Over-running clutch

22. Starter Diagnosis

24. Allow the armature to drag on the pole shoes
Worn out bushings...
Allow the armature to drag on the pole shoes
This will slow the starter and INCREASE amp draw

25. Worn or Dry Armature shaft will INCREASE amp flow

26. Burned commutator bars restrict the amp flow

27. Worn out brushes DECREASE amp flow

28. There will be more questions...
...On the test….
…than I am covering here.
Read your book…
and complete Starter Labs

29. Test the Starting System
Check Cranking RPM
Check Cranking Volts
Check Cranking Amps

30. Low Cranking RPM A slow turning starter will pull extra amps
Could be caused by tight engine
(New Engines)
Can be caused by advanced timing

31. Low Cranking RPM Low cranking RPM…. …With low cranking Amps…
Bad Starter
Worn brushes, Bad commutator bars, open in field or armature

32. P = I x E Cranking Volts Power is required to turn motor
Low volts will cause high amps

33. Low Cranking Volts Cranking volts at battery should be over 10V
Load test battery if low cranking volts
Excessive amp draw can cause low cranking volts in a good battery

34. High Cranking Amps Check voltage drop across STARTER MOTOR
If Battery cranking volt is 1/2 volt more than Starter volt drop diagnose battery cables and connections

35. If cranking volts are within 1 volt of battery…
Insure engine turns freely
Insure ignition does not cause slow turning engine
Replace Starter Motor
(assuming there are excessive amps)

36. Before you install the rebuilt starter
Bench test the replacement
It may save you a starter R & R

37. Starting Systems Understand the operation of the two starting circuits
#1 Starter Control Circuit
#2 Starter Motor Circuit

43. Starter Solenoid
Understand the function of the Pull In solenoid windings….
…and the hold in solenoid windings

46. Starter Solenoids
Predict the effect of an open circuit in the solenoid pull in windings….
….and the solenoid hold in windings

50. Notice pitted contact ring

51. 24 Volt Series/Parallel Switch
Understand how 12 volt batteries can be used to run a 24 Volt starting system

54. Series/Parallel Switch
Diagnose a defective series parallel switch using a volt meter

59. Starter Control
Identify variations in starter control circuits

63. Test the Starting System
The Bottom Line
Test cranking RPM
Test Cranking Volts
Test Cranking Amps