Onan 2500 generator propane

[ray]

It chugs along with no load puts out 120. When I ad a load its starts surging putting out unlevel current.
I have changed the spark plug, added more propane, checked the oil and it’s ok. The carburetor has no adjustments.
Has anyone had this problem? Any ideas would be welcome.
Thanks
Ray

[markopolo]

I saw this on Onan's FAQ page: http://www.cumminsonan.com/rv/support/faq/

Can LP fuel plug up the regulator?

The most common contaminants found in LP fuel are the oils from the LP pumping facility. The oil is removed from LP fuel at the location where the fuel vaporizes. In liquid withdrawal LP fuel systems, this occurs in the regulator. Oil contaminants can then clog the regulator. The larger QG series generators liquid withdrawal LP fuel systems provide a drain for oil removal. See your Cummins Onan Certified RV Service and Parts Dealer for assistance.

I had to empty my propane tank once to replace a gauge and there was a fair bit of oil in the tank.

Also, on my gasoline Onan, the no load voltage should be typically 125volts and full load voltage is 118volts per service manual specs. I don't know for sure but 120volts no load might be too low.

[Mike]

Originally Posted by ray

The carburetor has no adjustments.

If it's not a gummed up regulator by the oil, maybe it's a fuel/air mix problem.
Sorry for asking but, is there an altitude adjustment on it anywhere that you can find?
If there is maybe check/adjust that, as I recently had my gas genset serviced and it was
mentioned as a possible cause (too rich/lean) of surging while running under load.
Here's a link to some discussion of what is and isn't on some gensets and what may be
causing problems with air/fuel mix. Some mention the LPG models do have an altitude
adjustment of some sort.
Bottom line, if you aren't able to figure it out, get to an Onan repair facility.
Possibly expensive, but may be worth it.

[carrothers]

I had a similar problem with Onan surging with and without load. Onan dealer replaced $650 worth of parts and still didn't correct the problem. finally, they took the unit out of the RV (underneath on my Road Trek) and disconnected the oil level sensor. It has worked fine every since. Tech said that Onan won't admit they have a problem and won't officially condone a registered service tech disconnecting this sensor; but if the customer demands it they have to do it. I just check my oil level every 10 hours; but it hasn't used any oil in the first 50 hours of operation. Tech says change it after 100 hours. It cost me over $1000 to find this out on a generator that had less than 5 hours on it; but it was over a year old and Onan would not warranty the work. I was and still am very disappointed in Onan that they know they have a problem and won't address it.