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Ask Hank F. Your Own Question
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14535
Experience:  Certified on Onan and Generac generators
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Have a Kohler Generator 12RES propane fueled - have an OC

Customer Question

Have a Kohler Generator 12RES propane fueled - have an OC (over crank) message we can't get cleared. oil was low- fixed that problem, took off air cleaner outer cover filthy air cleaner itself looks clean, going to check spark plugs next. generator set has 482.8 hrs on it. What, if anything, should I try next?
Submitted: 1 year ago.
Category: Small Engine
Customer: replied 1 year ago.
have not heard from you
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Hank F. replied 1 year ago.

Hello, my name is ***** ***** I am going to assist you with this.

Does your genset shut down and give the OC code after 3 cranking attempts, or during the first cranking attempt?

Customer: replied 11 months ago.
It's happening during the first cranking attempt.
Expert:  Hank F. replied 11 months ago.

If it is setting the OC code after the first crank attempt, it is most likely the MPU gone bad, and the controller can not sense th signal from the MPU.

At the P1 connector, connect a voltmeter across pins p1-17 and P1-29. Red is positive, black is negative.

Crank the genset.

The MPU must put out a minimum of 1.75VAC while cranking.

If it does not, check the air gap of the MPU. It should be set at .020".

Let me know what you find.