Generator Keeps Shutting Down

I have a Onan 6300LP Propane genset on my motor home,

History – Bought the motor home 10 months ago and have been using it a lot. Generator has been running fine and only started giving me trouble a few weeks ago.

Symptoms – Starts and runs fine for up to an hour and then just shuts off. Most often it will only run for ten minutes. Once it shuts down will not stay running for more than a few seconds until I let it cool down.

Unit Status – Generator has 392 hours on it. I just changed the oil and filter and confirmed the oil level is correct. I used 15W40 standard motor oil. I also replaced the air filter (It had some yellow liquid in the filter. After changing and running it there was some clear liquid instead) Propane tank was just refilled, cutoff valve is fully open.

Tests Performed – 

• I checked air cooling passages to make sure nothing is restricting airflow for cooling the engine.
• I removed the brush block and cleaned the slip rings. Brushes were showing proper wear but sticking in the block. I freed them so they move properly, reinstalled brush block.
• I confirmed with a volt meter that there is ~129 volts at the circuit breaker on the genset while running.
• I took the wire off the oil pressure sensor by the oil filter and grounded the wire. Generator started and ran fine but still died out after 6 minutes.
• I disconnected the remote start switch. It seemed to run longer after that, but began dying out again.
• Pulled a spark plug, looked clean and not worn.

After these tests I read through the Flight Systems troubleshooting guide which indicated that the control board could be bad. I ordered a new one and installed it, and the generator started up fine and ran for several hours until I shut it off. I thought the problem was fixed but the next time I started it it shut down after six minutes. Back to square one.

My next line of exploration was propane regulators. There is one by the onboard tank and one on the generator itself. There is also an electronic safety switch on the generator that can cut off propane supply. My research led me to first check the vents on the regulators. I visually inspected the generator regulator vent and it looked free of obstructions. I noticed a button on the regulator for resetting it in case of a pressure imbalance. I pressed the button, then started the unit. It ran for maybe sixty seconds before shutting down. I pressed and held the reset button for several seconds and it hissed louder this time. I restarted the unit, and it has kept running just fine for an hour now.

Long story short, I wish I had known that this was a simple propane regulator reset issue!