Onan 4000 and Seafoam for Surging/Revving on Startup
On our 2020 Minnie Winnie 22R, we have the Onan 4000 generator. It's been pretty reliable, and I'm pretty good about starting it up about once a month. However, I had to let it sit in storage for two months during this summer in Texas heat while on a trip overseas. When I returned home, the next day I went to the RV storage and started the generator, and noticed that it was surging/revving for about the first 3-5 minutes. I then put it under load with the A/C, and it smoothed out after 5 minutes. Decided to visit the RV a couple more times over the next week, and the surging/revving now happens on each startup.
One other thing I should mention, is the carburetor was replaced under warranty by Cummins/Onan when I bought the RV new. It had apparently sat on the showroom floor for about a year, and no one started it up during that time. So its had a new carburetor since two years ago, and now has about 45 hours of run time.
In any case, consulted with YouTube and found several helpful videos using SeaFoam and a gallon of gas in a separate container. Disconnect the main fuel line, and run a fairly concentrated mixture of SeaFoam with premium gas (91 octane). All of the videos have different mix ratios, so I'm guessing it's not that critical to be exact. They run the generator for about 30 minutes, "hot soak", and then run it again for another 15-30 minutes.
As it would happen, I was on the phone to Lichtsinn RV talking to the service department about another topic, but brought my surging/revving issue up in the conversation. They suggested that on my next RV trip, run all the regular gas out of the fuel tank, and fill up with premium gas. Once I'm sure the tank has only premium, then add a can of SeaFoam. At that point, just run the generator for some period of time - maybe 30 minutes. Let it sit for a while, and then run another 30 minutes. Then after that, then just go back to filling up with regular gas.
This idea of just filling up with premium and pouring SeaFoam in the main gas tank would be easier. As it turns out, I'm planning about a 2000 mile trip pretty soon, and it's something I could do along the way. Of course I'll pay a bit more for fuel on those premium gallons of gas, but for the convenience of this alternative procedure would be worth it - if successful.
Before doing idea #2, I had some questions for the forum:
1. Are there any issues with running premium fuel and SeaFoam on the Ford V-10 engine? I should note that the engine has about 21K miles, and is running very good.
2. If the answer to the question above is no, what gas-to-SeaFoam ratio should I use? The gas tank has a 55 gallon capacity, but it seems like I should have something less than that.
3. Should I not consider this idea, and go with one of the YouTube video procedures?
2020 Minnie Winnie 22R with E-350/6.8L