Generac overspeed on starting cold - Generac Power Systems Electrical Supplies

SOURCE: 10kw Generac shut down overspeed

Make sure that the throttle linkage is all there and not damaged/misadjusted, then get a manometer and check your inlet gas pressure. Gas pressure should be 8 inches of water column and stay there running or not.

Carl

SOURCE: Attempted to start Generac Guardian 15 kw air

I work on these every day. Its either gonna be the rotor or stater, the voltage regulator, but most likely its a bad stepper motor which is the throttle motor, or control board. Thats all that could be causing that so its one of those. If its the rotor or stater thats bad it causes the generator to RPM up because it thinks its not producing enough power due to that. I had the same problem with the same one we just fixed and it was the slip rings on the end of the rotor so bad rotor.

SOURCE: Generac 43903 standby Generator overspeed indicator on starting

I have a generator that did the same thing. It would start and then stop within a few seconds. The more expensive generators have an oil level safety switch to prevent the engine from burning up. There is usually a wire connecting to the switch on the outside of the engine near the oil fill hole. Remove this wire and try to start the generator. If it runs without a problem then it is the switch. You need to remove the switch and take it apart carefully and clean it. There is a small float inside the assembly. When the oil runs low the float allows the switch to short to ground which kills the spark to the spark plug. Hope that helps.

Bob Janelli

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Testimonial: "This is good information in the event that the low oil switch is part of the problem."

SOURCE: Generac Guardian 15 kw overspeed fault

Did you remember to set the overspeed shutdown threshold on the control board?

SOURCE: Generac Guardian 12 KW Model 04456-2 shuts down on overspeed in cold weather

Leigh,
See my 5/22/12 comments on my "overspeed fault" problem resolution [Generac 43903 standby Generator overspeed indicator on starting] . If it only runs for a few seconds and then quits, you may have a similar condition to the one my unit had. A good technician should be able to diagnose the problem and determine if you have a similar failure to the one I had, or one of the other causes suggested by RSG000.