Onan generator only runs with switch held in

If you can get it onto a lift, replacing the voltage regulator in an underslung Onan Microlite 2.8 or 2.5 isn't hard, just patience-& dexterity-challenging, blindly feeling for a small tapped hole in the base pan that has NO lead-in or countersink, with the end of the screw. That's a real, real PITA (mine have only had one, a Torx).

Replacing the VR on ramps or the ground might be beyond all but the slimmest & most flexible. Dropping the generator _might_ be worth it, but all you achieve by having the cover off is a slightly better working angle accessing that dam'd screw hole.

You do need some minimal electrical savvy & a multi-meter to go thru the troubleshooting steps outlined in the Onan manual or on the Flight Systems website. I'd be darned sure that's what the issue was before buying one and going to the pain of replacing it.

Jim H.

stan909 wrote:
Did the OP ever get his fixed ? I wonder.

Yes I got it repaired at an RV dealer that specializes in working on the older classic GMC RV's that also had Onan generators. Total cost was $500.90 for dropping the generator and VR - $260 of that was for the potted electronic voltage regulator (some are charging over $400 for just the VR). Since my generator repair I have diagnosed the same identical problem for two other Roadtrek owners - this costly repair does not appear to be that unusual at all and according to my mechanic the main board with the starter switch (mother board) and VR are common repairs for the Onan. I also discovered that it is possible for you to replace the VR without dropping the generator, but replacing the two VR screws will be very difficult (some replace just one). Another approach I have seen is mounting the new potted VR on the outside of the Onan case - this method would be a much easier repair and could easily save you $500, since some are asking $750 and up to drop the generator and replace the VR.

I had that result when the problem was a ground fault in the motorhome's 120V system. But I read the codes to find out that was the problem.

I forgot to say that the repair cost me over $1000.

I actually have no patience but what was I going to do. I didn't want to put in a new generator for $2500+ and I am moving into a truck camper so the Class B was on it's way out anyway.

Did the OP ever get his fixed ? I wonder.

Wow. One year. You've got some kind of patience.

Don't know if anyone cares anymore about this thread, but after waiting over a year, I finally got my generator fixed. The list of excuses from the mechanic for taking so long was almost endless. The problem with the generator worked out to be the rotor - it had burnt copper that wound up taking out other parts.

loving retirement,

Sorry to confuse you but it could be several things - my mechanic is telling me it's the voltage regulator. I suggest you try to find a qualified service location that can work on Onan generators - maybe a good RV service location. You could try taking it to a Cummins Onan service location, but they might try to sell you a new generator.

powderman426 wrote:

Jim&Carolyn wrote:
What exactly do you mean by "older" or "newer" model? I don't see mine as a "newer" model.

What I meant was if it had electonics on it such as led or trouble code by number. The older units from back in the 70's and possibly the 80's had no troubleshooting features built in.

These last few posting on my original tread have me completely confused - "older or newer", "led trouble code by number", "blink codes" and "older units from back in the 70's and 80's." My rig that has the stated Onan generator problem is a 2002 Roadtrek and I can't find any blink codes, led trouble codes making me think I must have an "older unit" that was built around 2002. Do some Onan 2800's have blink codes and/or LED readouts and exactly which ones, what years and where is the readout?