ethanol killing generator--over and over?

[MarkieBob]

Dealer replaced the fuel pump in my ONAN generator because of the ethanol in the gas. He said I might have to do it once or twice a year because the ethanol is eating up the diaphragm in the fuel pump. And ONAN will NOT warranty it because of the ethanol. Why can't a fuel pump be constructed to handle that? Technology does nearly everything else? I may just use my Honda 2000 instead 😞 How many of you are having this problem? Any other solutions besides burning pure fuel (yeah, right--7 mpg on 50+ cent higher gas?)

[10forty2]

Ethanol will destroy an engine, but you can help it by adding Seafoam at 1oz/gal of fuel to every tank. My 1999 Onan 5.5 seems to like it!

[ArchHoagland]

I think I'd find another dealer. That guy is taking you for a ride.

[azrving]

The worst damage that I've seen is in 4 stroke carburetors. The bowl has to be vented to atmosphere and the ethanol is hygroscopic so it absorbs moisture and gunks everything up. Two strokes don't have a bowl, just diaphragms so they don't have as much problem and it would seem to apply to something like your fuel pump. I don't think the fuel will necessarily destroy the diaphragm but leaving it in there a long time may. We put a full sheet of paper notice on each piece of repaired equipment that said never use fuel over 45 days old.

[WILDEBILL308]

MarkieBob wrote:
I guess I don't start it often enough. Once a month for a couple hours?

Well there is a reason Onan recommends you exercise the generator. Putting a slightly rich dose of Stabill before you let it set should be cheap insurance. That and following the exercise routine called out by Onan.
Let us know how it works.
Bill

[A1B00902]

read this it may help

https://www.theglobeandmail.com/globe-drive/culture/commentary/the-problem-with-ethanol-in-gasoline/article29103634/

[ksg5000]

As others have indicated - that's rubbish. Onan work just fine without having to buy special fuel - find another place to have your RV worked on.

[gbopp]

mmccray100 wrote:
I've got an Onan 5000 in my 1999 Winnebago.... never had that problem and have never heard of it. Is somebody pulling your leg?

I have the same generator in our 1996 Southwind. No problems.
I run it, under load, about 45 minutes every month.
The OP needs a new dealer.

[rk911]

mmccray100 wrote:
I've got an Onan 5000 in my 1999 Winnebago.... never had that problem and have never heard of it. Is somebody pulling your leg?

same here. Onan gennys in two motorhomes over a 30-yr period and no issues like the OP is reporting. maybe inferior parts to begin with. a call to Onan is advisable.

[ILVMYGT]

Sometimes it is hard to find non-ethanol fuel and it can be expensive. On page 45 of the Cummins document (link) says that no more then 10% ethanol. This would lead me to believe that the equipment is designed to run on blend of ethanol fuel. However there are some challenges with blended ethanol fuel specifically when storing for more that a month or 2. The ethanol comes out of solution. There are several additives the help with that. The ethanol also cleans out the fuel system and can plug fuel filters. Your coach is new enough that the fuel system is designed for ethanol fuel. I would google ethanol fuel to understand the issues with it.

https://cumminsengines.com/uploads/docs/Cummins_Onan_Generator_Seminar_Apr_2017_002.pdf

[lryrob9301]

Your "dealer" is full of ****. That Onan will run on ethanol gasoline just fine. I've had two coaches with Onan 5500 gas generators and they ran with it with no problems.

[OLYLEN]

I would get an after market fuel pump. What Gen do you have, 2 hours should be good. Might also try Stabil in the tank.

LEN

[MarkieBob]

I guess I don't start it often enough. Once a month for a couple hours?

[mmccray100]

I've got an Onan 5000 in my 1999 Winnebago.... never had that problem and have never heard of it. Is somebody pulling your leg?