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Ethanol and small engines

On the mid-coast of Maine we are just getting supplies of gasoline with 10% ethanol. While I know this is no big deal for cars does it create any problems for generator, snowblower or lawn mower engines. I recently heard that it can damage carburetors? Hasn’t gasoline with 10% ethanol been available for some time in southern states? I’m not referring to E85.

Doesn’t for me. Here in NH been using it for years. There is no other choice. 10% is NOT a problem.

Most small engine manuals will tell you not to use it. I can’t imagine that you can’t get non-ethanol gas at all. In farm country like South Dakota its a little hard to find gas without 10% added, but is still available. The plastic seals and so on in the fuel systems don’t like it.

Ethanol is a replacement for MTBE in gasoline as an octane booster. The US Department of Energy says that these states ban MTBE:

California, New York, Colorado, Connecticut, Illinois, Kentucky, Michigan, and Ohio.

Even though It’s not banned in Maryland, I can’t recall the last time I saw a gas station selling gas without 10% ethanol (no MTBE).

Depends on when the small engine was built. Newer small engines are designed to handle a low concentration of ethanol in the gas. However, older small engine fuel systems can’t handle any concentration of ethanol in the fuel because it attacks the gaskets, seals, and even the metals used in older engines. This is why in Minnesota you can still purchase gasoline with no ethanol in the gas because it can damage the fuel systems in older small engines.


Many small engines use diaphragm type pumper carbs. These engines, especially older models, can have problems with ethanol. The old rubber parts just turn to goo after a while. Newer designs tolerate 10% ethanol just fine.

Marine engines tend to collect water in their fuel tanks…A little water in the bottom of the tank will cause the E-10 to separate (phase separation) into a cloudy witches brew that can really mess up a marine fuel system…

We have 10% here in NH and I’ve never had a problem with either my lawnmower or my snowblower.

I have found many articles stating the 10% ethanol gas will not do any harm to small engines. One question is, why would this question be brought up in so many different places if it wasnt a potential problem?
I searched for my own reasons…
2003 Yamah FZ1 - ran perfect until recently
2006 Yamaha Brun - ran perfect until recently
2008 Leaf blower - ran perfect until recently
2009 Toyo Lawn Tractor - running like crap
I know they are different kinds of small engines…but…they all ran very well until recently. They all have similar symptoms; sputtering, smoke from exhaust, need choke/enricher to start and run, want to stall at idle???
Person at Yamaha said tons of people have been bringing in bikes and toys with same problem(s). I had the Bruin and FZ1 serviced and the bike still sounds sick, not the good sick, the “how much more do I have to spend and how do I fix this problem” sick.
What gives…