Seeking Help - Generator Won't Stay Running

[ron_dittmer]

My brother is texting me for advice. They are on a trip. His 2800 Onan starts and stays running until he lets go of the start switch. The same thing happens with both start switches, the on-gen and inside house remote panel. Main fuel tank is 3/4 full, gas cap off to assure no built up negative pressure.

Anyone here have the same trouble and the solution?

[phil-t]

Same as what has been written. I had that same problem - turned out to be the brushes and commutator on the genny end. Not a cheap fix by a Cummins repair center.
Several other causes for that same scenario - fuel problem (of some sort), low oil (or bad oil sensor), control board.
The genny is belt driven and that can be an issue on some models.
Flightsystems.com has some good troubleshooting documents and are an excellent source for parts.

[stew47]

Happened to mine. Shop replaced a control board. Found out later a company makes better version. The company is flight systems.

[ron_dittmer]

Hi Everyone,

OP Here. Thank you for all your replies. I have shared your comments with my brother. His plan is to finish his trip without a working generator and make the repairs himself after his return.

After I posted my request for advise, he found an area RV repair center. The tech there said it was the voltage regulator (same diagnosis as some of your comments). He would have had the repair done there but it is a 2 week wait.

Thanks again for all the quick replies!

[Sam_Spade]

Check the oil level first.
There is a low oil sensor. Don't know if it would act like that though.

Is the light in the switch AT the generator flashing after it stops ?
If so, there is a simple procedure to get the trouble code.

Most any Cummins diesel shop also does Onan.

[Kamphiker]

Sounds like bad regulator and/ or Slip rings.
Has the Generator been getting a monthly exercise ?

Lack of running causes the brushes & slip rings to get corroded & can take out the regulator along with it.

[Kamphiker]

Onan Manuals available here

https://www.smokstak.com/forum/showthread.php?t=85628

Also they have a forum

[DownTheAvenue]

lm17 wrote:
I would start with checking the fuel pump.

The engine part of the generator runs until the start button is no longer depressed. A fuel delivery problem would not be related to the start button.

[DownTheAvenue]

The problem is electrical. The generator needs to see both 12 volts and 120 volts to continue running after the start switch is no longer depressed. Unless one is very familiar with this model generator and/or have tools and a shop manual, then a professional repair shop will be required.

[gkainz]

lots of good info here

https://groups.google.com/forum/#!topic/rec.outdoors.rv-travel/LNXtSh_3v2U

[MDKMDK]

I had to have a relay or solenoid inside the generator replaced a few years ago when the wiring to it corroded due to lack of exercise. It was responsible for engaging the "run" function after the "start" function got the motor turning over. Can't recall what it was called. It required the generator be dropped out of the Roadtrek to repair it. My symptoms were the same as your brother.

[lm17]

I would start with checking the fuel pump.