Guardian 7500 by Generac Generator Question

[gregm784]

When i fire up my gen it makes AC for roughly 7-10 seconds then AC power quits.  Troubleshooting shows voltage at the main circuit breaker is 159v AC.  When i'm in the generator area, i can hear something 'click' (like a breaker) and the red light on the regulator goes out.  After 30 seconds off (roughly) it clicks again and if i restart the gen, i have AC power again until it repeats. 

I can't locate the click.  Does the voltage regulator have a over charge protector in it?  Do i have a bad regulator?  that's what i come up with, but not sure.

 

[Roy M]

The high voltage indicates the regulator is the problem.

 

[Gary RV_Wizard]

The voltage regulator monitors the voltage output and adjusts the engine rpms (opens/closes the throttle) to maintain the correct voltage & frequency. Your symptoms suggest either the regulator has failed or the engine is unable to respond to its call for more or less RPMs.  Most engine-related problems are low voltage or frequency rather tan high, so I'm guessing yours is a regulator problem.

 

[Charlie 5320]

The voltage regulator monitors the voltage output and adjusts the engine rpms (opens/closes the throttle) to maintain the correct voltage & frequency. Your symptoms suggest either the regulator has failed or the engine is unable to respond to its call for more or less RPMs.  Most engine-related problems are low voltage or frequency rather tan high, so I'm guessing yours is a regulator problem.

Voltage has NOTHING to do with engine RPMs on a generac generator. They have a mechanical governor that has to be set for RPM. The governor needs to be set with a tachometer or can be set for HRZ output.


To the OP, if the throttle linkage is bound up, it could cause an over voltage condition, therefore it stops producing power. Voltage that high can and will cause damage to your appliances. I would take the air cleaner off and spray the linkage with carb cleaner while working the linkage, ENGINE OFF. Did it start doing this all at one time or has it been increasing RPM over time? If after you clean it, and it continues to over voltage, turn off the breakers, hook up a meter and start it. If the voltage is too high, move the linkage with your hand to see if the voltage drops. I could be a linkage problem or voltage regulator problem. There is a little blue pod on the regulator, next to the led, turning it CCW will reduce the voltage. If you have to do this the regulator is on it's way out. NEVER shut the generator down with a load on it, the regulator don't like that.

 

[gregm784]

The throttle linkage is free & clean and responsive.  I'm going to place an order for a VR and hope that fixes it. 

Thank you for all the input.  i'll check RPM this weekend first.

 

[Charlie 5320]

The throttle linkage is free & clean and responsive.  I'm going to place an order for a VR and hope that fixes it. 

Thank you for all the input.  i'll check RPM this weekend first.

Try turning the little pot screw CCW first. You will have to adjust the new regulator most likely. Turn the little screw about 1/2 turn and check it again. Blue pod with a white screw.
 

 

[gregm784]

I checked the RPM. It was a few hundred high, now within spec.  that put me at 126V.  I backed the pot adjuster off and now it hovers between 119.8 and 120.4 no matter how much load is against it. 

THANK YOU !!!!!!!! I appreciate all the knowledge here.

 

[Charlie 5320]

I checked the RPM. It was a few hundred high, now within spec.  that put me at 126V.  I backed the pot adjuster off and now it hovers between 119.8 and 120.4 no matter how much load is against it. 

THANK YOU !!!!!!!! I appreciate all the knowledge here.

That 126 vac was fine. Check it with both airs running, after it warms up real good. If your meter does hrz, make sure it's set at 60 loaded .