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americanrascal's avatar
Dec 15, 2015

Onan 4000 KY Clicking sound?

Our rig is about 2 yrs old with a 4000KY Onan gen set. It has about 160 hrs on it and runs smooth and well. It is used and cycled regularly (about every 2 weeks for 1-2 hours) under load.

But of late its started a loud and noticeable intermittent clicking sound. I note no deterioration in its running, it runs smooth, no error codes, starts relatively easily.

I pulled the cover to check for rubbing on the cowling but the clicking continues.

Any ideas what to suspect? My mind is thinking its an impending fuel pump issue?
  • Do you have any rodents nearby with a propensity to drop a nut or seed into the cowling?
  • Now the fun begins. This is what we called the hunting game. When it starts clicking. Put your hand on the solenoid body. See if you can feel it moving. You might also put your hand on the valve cover. Feel for the clicking. Also check the floor where the genset mounts. Look for anything that could be hitting the frame.


    OK will try detecting action on solenoid. Tried tapping it yesterday to get it to make a sound but no result. Will try to feel with my fingers if its activating. I will also check valve cover but that seems more towards rear of set and sound seem to emanate forward. All seems OK with the floor of the set. The solenoid is silent however when I engage the starter. Can't even hear it click, but will still check again.

    My first thought was the starter bendix creeping out and touching the ring gear


    I assume that would involve removing the starter and looking for wear? Could be though.

    Do you have any rodents nearby with a propensity to drop a nut or seed into the cowling?


    Yes I have the usual covey of squirrels in our yard but no evidence of their being anywhere near the unit or eating in the area.


    Thanks for the input folks. I will attempt to check all today (after the rain :) )
  • You don't want to remove the starter unless you absolutely have to. It's not that it's a conceptually complicated job, it's just that the starter is completely inaccessible without removing the top cover from the generator, which generally means removing the generator from the RV. This, in turn, usually means disconnecting all the wiring (and the AC connections are rather deeply buried), the fuel line, and manhandling things with a floor jack or similar.

    If you do have to remove the generator by dropping it down, measure the clearance under the side of the RV before you start and see if you might want to jack the RV or put it on ramps or something. It's not very much fun to try to work on a generator that's dropped but still imprisoned under the RV.

    Don't ask me how I know this.
  • Did anyone figure out what was going on here. We have the same issue. Generator runs perfect but every once in a while when we step outside the RV we can hear clicking coming from the generator. We thought it was the weather here in the Midwest we are from Arizona and never noticed it out there but then again we only ran our generator out there at night when we watched the satellite to many hours during the day for our solar to charge our batteries all the way up...
  • This is what mine is doing. A Cummins authorize service center said it's gonna make this noise.. I don't remember it doing this before.. Hum.. https://youtu.be/6D4o3BUbYfk
    Any opinions welcome
  • Glad to have found this thread. When working in my trail boss conversions horse trailer and running the generator I noticed a regular ticking coming from the control panel area. Now I know it is normal and coming from the gen control meter. :)