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Old 07-30-2021, 02:10 PM   #1
Junior Member
Brand: Thor Motor Coach
State: Michigan
Posts: 5
THOR #24371
Onan Generator Question


I have a 2018 Thor Four Winds Sprinter with a Cummins Onan RV QG3600 LP generator. When I first start the generator, it spits and sputters for about 30 seconds. After running 30 seconds or so it seems fine. Almost like it needs to "warm up" but I don't think that makes sense since it's running on LP and I don't recall it doing this before. It runs strong for hours with no sputtering.

I've done some basic trouble shooting and research online and it seems like it could be the regulator. I would like to confirm this before digging in too far since it looks to be pretty hard to get to.

Please see the video here:

Any input would be appreciated.

Thank you!

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Old 07-30-2021, 02:16 PM   #2
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Brand: Thor Motor Coach
Model: ACE 27.1
State: Florida
Posts: 9,721
THOR #7035
I would agree with your "regulator" assessment (the one on the generator engine). If it was a gasoline generator I would say it had carburetor issues by the way it's running in the video.

I'm assuming this didn't just start right after filling the propane tank and all other propane appliances are working correctly?
Ted & Melinda
2016 ACE 27.1
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Old 07-30-2021, 02:29 PM   #3
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Brand: Thor Motor Coach
Model: Axis 24.1
State: Connecticut
Posts: 1,153
THOR #20289
It may just be air in the propane lines. I don't have a propane generator, but I know when I first light the gas burner after sitting for a few weeks, it burns yellowish and sputters a bit for maybe 30 seconds until it settles down.

I don't know if the air leakage (if that is what it is) is due to normal leakage in the solenoids for the water heater, furnace and maybe the gas valve on the stove or leakage at the various fittings underneath for propane.
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Old 07-30-2021, 03:08 PM   #4
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Brand: Thor Motor Coach
Model: 2011 FW Hurricane 33T
State: England
Posts: 949
THOR #16471
I do not have an LP generator, but found this interesting. Maybe the regulator vent needs to be looked at...?

Good luck
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