Fuel with ethanol begins to turn after one week. It’s an organic substance made from corn. It doesn’t want to stay chemically bound to gasoline, and will separate from it. Itabsorbs moisture,whichcauses ethanoltogel. It rots rubber, corrodes metal, and generally causes havoc within any fuel system. Note: If you have hand-held equipment with clear fuel lines; over time, youwill see an accumulation of ethanol. Ethanol will coat the fuel lines, as well as your carburetor. Adding a fuel treatment to your oil/fuel mix fuel will cut down on the time it takes to have this happen.