Problems with E10 fuel in Onan's?

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Problems with E10 fuel in Onan's?

Unread post by Dodgy71 » Thu Mar 17, 2016 12:43 pm

E10 (10% ethanol in gasoline) fuel is about all you can buy in the US these days, unless you are buying race gas, aviation gas, marine gas, or 1 qt bottles of lawn equipment gas, thanks to alternative energy efforts :x \n The 3 big problems with ethanol in gasoline are that it "phase separates" meaning that the ethanol separates from the gasoline really quickly (like about 30 mins), the ethanol sucks up water from the atmosphere (much like brake fluid), and the ethanol attacks rubber (like fuel hose, fuel pump diaphragms, and rubber carb pieces), unless it is specifically formulated for use with ethanol.\n The effects of the first problem are minimal in a daily driven vehicle, as the vibration from driving tend to mix the ethanol and gasoline, so that you don't get a big hit of either. For vehicles that sit, or are stored, it can be a much bigger issue, as your fuel pickup may be picking up pure ethanol after a start from a long sleep, and the engine won't run too well on pure ethanol. BTW, the ethanol, when separated, is below the gasoline.\n The effects of the second problem are much more damaging to vehicles which are driven such that full tanks of gasoline are not used within 30 days. The water sits at the bottom (below the ethanol) of the fuel tank, fuel lines, and carburetors (if you have one). This water can rust tanks and fuel lines, and really corrode aluminum (in your carb).\n The third problem effects all equipment with a gasoline engine, that is more than a few years old because the rubber that was used was fine for 100% gasoline, but not OK for ethanol. This means that anything with a carburetor is far outside of the safe zone for E10 and rubber items.\n There is a tremendous amount info on this subject on the web, and the problems are well documented for many types of equipment (aviation, marine, small engine, and automotive). Even the auto manufacturers will not warranty use of anything more than E10 (unless a flex-fuel vehicle), because even with stainless fuel tanks and hard lines, and ethanol proof rubber in the fuel injection systems, the water is just to damaging.\n OK. Finally to my question. Are any of you having trouble running E10 in your "vintage" Onan's? And, have you done anything to mitigate the issues that E10 causes (such as replacing rubber fuel lines with ethanol approved, switching a diaphragm type fuel pump to an ethanol safe vane type, running the generator dry of fuel after use, etc.)?

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Re: Problems with E10 fuel in Onan's?

Unread post by KB2CRK » Thu Mar 17, 2016 1:33 pm

The only thing I have done is add Stabil when it is going to sit. I also exercise the generator monthly by starting it up and running it under load for about an hour.

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Re: Problems with E10 fuel in Onan's?

Unread post by 77Travco » Thu Mar 17, 2016 1:42 pm

I've never had an issue. I drive my Travco and exercise the genset about every 5 or 6 weeks or so. Keep in mind that the generator pickup tube only goes down to the 1/4 tank level... well above any separated ethanol that may be lurking at the bottom of the tank.

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Re: Problems with E10 fuel in Onan's?

Unread post by Dodgy71 » Thu Mar 17, 2016 2:02 pm

77: Very good point!\nKB: Exercising once a month sounds like a very good idea!

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