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ATG (MarApr16) – Starter Not Turning Motor

HJ writes: How do I fix my starter to turn motor over?

According to Roger: Failure of the engine to turn over is due to several different areas:

1) Low battery voltage is one, and must be addressed first before moving forward. The battery must have a nominal voltage of 12 and fully charged voltage of 12.72. The battery must be able to hold voltage under a 80 to 100 amp load of 9.6 volts. Replace battery or repair any defective cable connections to ensure proper voltage to start the car.

2) The Starter/Generator on a golf car does two things. First it turns the engine over for starting the engine. Secondly, it performs as a generator to keep the battery charged. Understand a Starter/Generator (SG) is nothing more than an electric motor. On some older cars (with two cycle engines) the SG must turn Clockwise and Counterclockwise. Four cycle engines will turn in whatever direction the engine manufacturer chose to use. So make sure of direction as once in a while someone will install a battery backwards and bad things happen. Do not trust what someone before did or said they did.

3) Mechanical damage such as a SG bearing locking up. Disconnect the SG belt and spin the pulley by hand making sure the armature can rotate without locking up. Turn the engine over by hand. Does it turn freely or lock up? Locking up is engine failure not SG failure. And can explain why the engine does not turn over.

4) Now let’s talk about the SG itself. As I do with most everything I do not just jump in and start replacing things or tell someone to start replacing things. I always look at procedure of why and how. Things we just talked about are things I categorize as known factors. Now we look into unknown factors.

5) If you look at the simple diagram notice there are 8 key components. Failure of any one of those components and the cars engine will not turn over. Based on comment number 1 we have a working battery. We start by confirming we have nominal voltage at (A) and (B). If we do we continue, if not we have cable issue, battery issues or ground issues. We will use the term ground through out as being negative. Continuing on we should see nominal voltage at (I). If that voltage is missing the key switch, fuse or a wire has issues. If voltage is present depress the accelerator pedal. We should now hear an audible “clicking” of the solenoid. If you do not, check for nominal voltage at (K). If that voltage is missing either the foot switch or wiring is an issue. If voltage is correct. Check for a ground voltage at (J) and if missing check fuses or grounding circuit. If the ground is good and nominal voltage is seen at the solenoid, the solenoid is defective. If the solenoid does click, check for nominal voltage at (C). If it is not present and the solenoid did “click” the solenoid is defective. If we see nominal voltage at (C) confirm we have nominal voltage at (D). If not that cable has issues or we missed something. If we have nominal voltage, check nominal voltage at (E). If nominal voltage is missing at (E) a motor brush (not shown) is open or a field connection is open inside the motor. If nominal voltage is seen, test nominal voltage at (F). If nominal voltage at (F) is missing we have cable issues or missed something. Nominal voltage present, then check nominal voltage at (G). If nominal voltage is not present at (G) we have a armature brush open or lead broken inside. If nominal voltage is present then the motor is not grounded to the frame or the engine is not grounded to the frame.

6) Old two cycle engines will need to be done the same way but include the inset drawing showing a mechanical switch for field reversing.

7) Should the engine just turn over slowly that again indicates comment numbers 1, 2, 3 or poorly seated motor brushes, defective armature or fields. This is the basics and should get you started and close to the problem area.

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Cartoon: March / April 2018

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