Cummins / Onan 6500 propane gen cranks but stops after a few min.

[HagerHawk]

Just bought my motorhome and it has a recently replaced 5/2015 Cummins / Onan 6500 generator that runs on Propane. The unit only has 152 hours since they replaced it. They also told me it has not been used since June of 2020

While the unit will crank, it will not stay running for more than a few minutes. Varies each time I get it to crank. I'm getting a generic code of 36 (Engine cutoff) most of the time and a couple of times I got a code of 15 (Frequency issue) which states to lighten the load and restart. I'm not running any load that I know of as all the appliances are turned off. No heaters running . Maybe refrigerator is on propane. 

Any ideas what I might troubleshoot? Why it will not remain running?

Thanks,

Tony

Edited January 5, 2021 by HagerHawk

[desertdeals69]

Propane regulator might be full of oil.

[kaypsmith]

12 minutes ago, desertdeals69 said:

Propane regulator might be full of oil.

Or how cold is it outside? When was the last time the propane tank filled? I use a propane generator also, and had the same issue to date three times in the last five years. Every time thus far it has been the result of an overfilled propane tank. If too cold side, propane can give the same results. Also check the radiator coolant level, this will shut down the unit, as well as low oil.

[HagerHawk]

2 hours ago, kaypsmith said:

Or how cold is it outside? When was the last time the propane tank filled? I use a propane generator also, and had the same issue to date three times in the last five years. Every time thus far it has been the result of an overfilled propane tank. If too cold side, propane can give the same results. Also check the radiator coolant level, this will shut down the unit, as well as low oil.

Temperature today was close to 70 deg, I just had the tank filled on the way home from picking up the Coach, Gage showed it to be 3/4 but now it is already showing 1/2

Could I have a possible leak and it is pulling air?

[wildebill308]

36 minutes ago, HagerHawk said:

Could I have a possible leak and it is pulling air?

I would check for leaks and possible bad regulator on thee system. Does your stove work? Other propane appliances?

Bill

[manholt]

I would not be using the tank until the problem is resolved....Please don't light a match!!!

[HagerHawk]

9 hours ago, wildebill308 said:

I would check for leaks and possible bad regulator on thee system. Does your stove work? Other propane appliances?

Bill

Yes, stove works and fridge seem to be working

[wildebill308]

So my scientific wild *** guess is it is the regulator going to the generator not giving it enough propane to stay running. Could be gummed up from non use.

Bill

[kaypsmith]

Again, be sure to check oil and coolant levels. From 3/4 to 1/2, (don't know how long between) "maybe leak", but not likely, propane goes out if leaking, and has an odor, so unless there is a smell, probably not a leak large enough to amount to your size problem, certainly can not hurt to check for leaks for safety sake. Try putting a load on the generator next time it cranks to make sure that it is producing current and see if it runs longer. Some older models generators used an exciter to start the generator function, if no current from generator, it will self stop the engine. If your fridge is on propane, it should be showing LP, if AC then it is on AC. What is the model # on generator?

Edited January 6, 2021 by kaypsmith

[kaypsmith]

If you don't have a manual, here is pdf link to probably same generator that you have, Page 51 shows fault code that you referred to, page 54/55 have some pertinent info.

https://www.granddesignrv.com/sites/default/files/Cummins Onan Generator Manual.pdf