Generac 43903 standby Generator overspeed indicator on starting

I can check that, but my unit has a low oil LED but it has never come on, and I added some oil to the unit but it still would not work correctly. A local Generac-trained technician thinks it may be a sticky governor, however, and is sending some repair diagrams. I did try moving the throttle lever to and fro, and start it manually several times... it seems to have started working again, but I don't know if it really solved the problem. I will try starting it manually for a while in a few days to see if that helps. I can check that, but my unit has a low oil LED but it has never come on, and I added some oil to the unit but it still would not work correctly. A local Generac-trained technician thinks it may be a sticky governor, however, and is sending some repair diagrams. I did try moving the throttle lever to and fro, and start it manually several times... it seems to have started working again, but I don't know if it really solved the problem. I will try starting it manually for a while in a few days to see if that helps.

Thanks for the suggestion Robinmar. The battery is still good (3 years old/5 year battery) and the unit cranks and starts OK. It is a sealed type and since it starts the unit I don't want to break the seals yet. It turns out that starting it on Manual 5-6 times with some rest in between seems to solve the problem at the time finally, and I let it run 5-10 minutes to make sure.

But after a month or two, it often re-occurs. The unit does run once a week on the schedule, but if the over-speed problem occurs, I need to do the manual starting until it works again.

I don't know if it is just a lubrication problem with the governor mechanism or what. I am going to contact Generac to see if they have any experience with this problem. Thanks for the suggestion Robinmar. The battery is still good (3 years old/5 year battery) and the unit cranks and starts OK. It is a sealed type and since it starts the unit I don't want to break the seals yet. It turns out that starting it on Manual 5-6 times with some rest in between seems to solve the problem at the time finally, and I let it run 5-10 minutes to make sure. But after a month or two, it often re-occurs. The unit does run once a week on the schedule, but if the over-speed problem occurs, I need to do the manual starting until it works again. I don't know if it is just a lubrication problem with the governor mechanism or what. I am going to contact Generac to see if they have any experience with this problem.

After working with a local Back-up Power service technician, the problem turned out to be a loss of the energizing current on start up which establishes the 12 vdc to activate the various sensors, and caused the false "overspeed" indication which shuts down the generator after 5-10 seconds of running. It turned out that Generac has a repair kit which solves this problem! I found that the Generac recommended service company in Northern Nevada, APS-FAB, knows how to diagnose this problem and how to order the repair kit (although I had to contact Generac support management to find out about this solution, and the repair kit came without any installation instructions, so proper modification of the circuit was a bit of a trial and error process). The modifcation assures 12 vdc to energize the sensors even if the process circuit board fails to do so, as was the case for my unit. The faliure became evident after 2+ years, intermittent at first, and finally a hard failure. Replacement of the main PC circuit board also solved the problem, but costs over $200 just for the part. So, "overspeed" fault, in my case, had nothing to do with the governor or the actual speed control of the unit. I commend Generac for providing a low-cost fix to this problem which seems to be a fairly common mode of failure, but most folks will need the knowledge and diagnosis of a field service representative to resolve these problems. After working with a local Back-up Power service technician, the problem turned out to be a loss of the energizing current on start up which establishes the 12 vdc to activate the various sensors, and caused the false "overspeed" indication which shuts down the generator after 5-10 seconds of running. It turned out that Generac has a repair kit which solves this problem! I found that the Generac recommended service company in Northern Nevada, APS-FAB, knows how to diagnose this problem and how to order the repair kit (although I had to contact Generac support management to find out about this solution, and the repair kit came without any installation instructions, so proper modification of the circuit was a bit of a trial and error process). The modifcation assures 12 vdc to energize the sensors even if the process circuit board fails to do so, as was the case for my unit. The faliure became evident after 2+ years, intermittent at first, and finally a hard failure. Replacement of the main PC circuit board also solved the problem, but costs over $200 just for the part. So, "overspeed" fault, in my case, had nothing to do with the governor or the actual speed control of the unit. I commend Generac for providing a low-cost fix to this problem which seems to be a fairly common mode of failure, but most folks will need the knowledge and diagnosis of a field service representative to resolve these problems.

yes i have a generac model 04109-3am having the same problem for the last three years after having three different dealers here in the birmingham al. area and around $1000 spent i still have problem yes i have a generac model 04109-3am having the same problem for the last three years after having three different dealers here in the birmingham al. area and around $1000 spent i still have problem

Trollpaint, See my post of May 23 - have your service company check for the 12 volts that should be generated upon starting, which supplies the sensors. In my case, that voltage was intermittant or missing and that caused the control board to not find the speed sensor signal, resulting in the false overspeed indication. Trollpaint, See my post of May 23 - have your service company check for the 12 volts that should be generated upon starting, which supplies the sensors. In my case, that voltage was intermittant or missing and that caused the control board to not find the speed sensor signal, resulting in the false overspeed indication.