onan generator dies out after about 5-10 minutes

[banjoman]

I started my onan generator on my 2001 Roadtrek and found that it would run for 4 or so minutes with no problem and then sputter and die out as if were running out of gas.
There is ample fuel in the vehicle and I have never had this problem before. It sounds like it is running out of gas but when I restart, It will run fine and repeat the cycle.
I have never had a problem with the onan and do run it monthly as per manual.
Any ideas where to start the troubleshooting?

[booster]

Originally Posted by banjoman

I started my onan generator on my 2001 Roadtrek and found that it would run for 4 or so minutes with no problem and then sputter and die out as if were running out of gas.
There is ample fuel in the vehicle and I have never had this problem before. It sounds like it is running out of gas but when I restart, It will run fine and repeat the cycle.
I have never had a problem with the onan and do run it monthly as per manual.
Any ideas where to start the troubleshooting?

There have been several similar problems folks have had with Roadtrek generators mentioned on the Yahoo board lately. Very similar symptoms and usually wound up being fuel related. Possible fuel pump failing, plugged up filter, or as was the case a couple of times, air leaks in the fuel line which showed up after folks put on a clear fuel line and could see bubbles. One was a bad connection at a fitting in the Onan case, and another was a crack in the fuel pickup in the tank.

[Robert1776]

I am responding late to this post, but I just went through this same problem on my Onan gas 2800 on my RT190. It would run for three or four or five minutes and just stop. Then pushing the start would not start it. After it sat for several hours I could start it but it did the same thing. I took it to a mechanic that I know and he found that the last time the oil was changed (a few months ago) too much oil was put in. I wondered why the shop put two quarts into a one quart capacity Onan. He drained the oil down to where it just reads full and now it runs normally again.

I hope this helps you as I called an Onan service center and they wanted $135 an hour with three hour minimum just to diagnose.

[mkguitar]

neat tip on the over oiling...
I do my own fixin'

OP, as above it could be fuel related.

gas formulations these days play havoc on carbed machines, and gas left to sit in a carb float bowl can gum up the carb ( which onan owners seem to replace rather than repair...when they go to a dealer...about $600).

If you have easy access to the fuel line, I'd suggest you add a petcock up by the rear wheel well that you can access.

you'll need to run the gas tank down before doing this...below 1/3 on many models, and use a vice grips to clamp the rubber line


While you have the fuel line apart for this, inject a carb cleaner which will hopefully loosen the gunk in the carb...and let that sit for hours.

reconnect fuel line with tap open


and run the starter- most vehicle starters should not be run for more than 20 seconds...and should rest for 5 minutes or better between cycles.

once the genny catches, then run the ac or other electrical load to get the genny working.

hopefully at this point it is working well.

let run for 30 minutes or more.

then turn off


later, start it up again

and if it runs perfectly and normally, turn off the electrical loads & turn off the fuel petcock.

let the genny run until it starves for gas ( carb float bowl empty)

every few weeks, hit the starter just to splash some oil around the genny motor internals.


use the genny when you need, just open the petcock...and everytime you store it, turn off the fuel and let it starve for gas & stall.

gas formulations and the midwest corn farmer mandated income policies are really hard on carb systems and esp on small motor which are used infrequently...lawn mowers, chainsaws etc etc.
The 10 or 15% ethanol added to fuel works ok in most fuel injection systems due to high line pressure to the injectors...but bad for carbs.

Mike