If gasoline with 10% ethanol is stored for a few weeks, will the ethanol evaporate?
I have read that to check for ethanol in gas is to add a little water to a container; mark the level and add gas. If the water lever stays the same, it is ethanol-free. I purchased ethanol free-gas and it passed the test. I then tested some gas with 10% ethanol that had been stored for approximately 1 month in a plastic gas can and got the same results. According to my source, the water/ethanol level should have gone up.