Ethanol is unfriendly to various flexible fuel system components. I'm unclear on why you would be using it. There is a fuel available in some gas stations that contains a few percent of ethanol and is sold slightly cheaper than pure petrol, but it gives inferior fuel consumption to almost exactly the same extent as the price saving, so it makes little or no sense for cars. (Ethanol requires an air fuel ratio of 8 to 1, compared with 14 to one for petrol. A litre of ethanol only has around 60% as much energy as a litre of petrol.) For a small engine with polymer components in the fuel system, using a fuel containing ethanol is a pretty dumb idea unless the fuel system has been designed specifically for ethanol, which would cost considerably more to manufacture. People in most parts of the US are stuck with having ethanol in their fuel - we in Australia are not, we (so far) get a choice. In my view it is a very easy choice to make.
