Onan Generator issue

[dryflie]

So this is not exactly a camper problem but the Genset is connected to it so it might qualify. Bought a used Sunline last year with a Genset on the back end. Got it all wired correctly and it starts and runs but only if I hold down the start button (either at the generator or the inside remote start). It will run just fine as long as that start button is depressed but once my finger is removed it dies. It's getting gas, oil is brand new, as I said it will run fine for minutes with the start button depressed. The cover is on so if was a safety interlock that's not the issue.

Any clever ideas?

Thanks
Al

[EMD_Driver]

Hi Al,


What type of gas, does the genny run on? Gasoline, or LP gas?


Gary

[JohnB]

Hi Al

We are A ok asking for help fixing anything connected with camping or a Sunline, so a Gen set for sure qualifies.

While I don not know your exact Gen set, I use to have a small engines repair business a long time ago so there are only some many things that can cause what you are describing.

If it runs great with you holding the button and dies when you release it, it points to the switch or something some how killing the ignition.

Do you know if this unit has a magneto or a coil for the spark ignition? If it has a magneto something is grounding out the run signal as that is how you stop them. If it is a coil that runs off a battery used for electric start, then the power to the coil if dropping out.

Do you have a volt meter? And are motor electric friendly?

And what about an Onan Model/serial number. I can look up and see if they have a cut sheet on exactly what you have so I can see what you are up against and better point where to go look.

I know Kitty and EMD_Driver have and Onan genset but do not know models etc.

Glad to help as I can

John

As a last resort some pics with showing the system electrical so I can figure out what you have.

[kanyonkitty]

Our Genny is an Onan 3600LP (propane) if that will help, I can get the manuals out, (but NOT tonight).

Kitty

[dryflie]

Thanks for the replies. A bit of research on my part has turned up some answers. Turns out that this problem is very very common for generators that have been inactive for long times. There are three possible reasons for the problem.

1. The generator isn't producing any AC output. This would point to a wiring problem perhaps. The control board prevents the engine from continuing to run.

2. A bad regulator does the same thing.

3. Most common cause of all is a stuck LOP (low oil Pressure) switch. Inactivity make this switch stick and once again the control board prevents the engine running to avoid damage.

So I've got to get the trailer to an RV shop with Onan experience and hope they can pin the problem down. Good thing is that the generator does run fine with the start switch depressed so hopefully once the problem is determined and corrected we'll be making power.