Tests conducted by Valvoline Oil Company have shown a slight increase in lubricity, and have put these concerns to rest. Because ethanol absorbs water in the fuel tank and lines, it can help to prevent the accumulation of water in the gas tank. However, if excessive water is absorbed, a phase separation could occur, resulting in a mixture of alcohol and water in the bottom of the tank. This would make it very difficult for the engine to operate and can cause corrosion. By taking caution that no water enters the system, ensuring that the equipment has a properly sealing tank cap, and by filling the tank before extended storage periods, the probability of excessive water in the tank can be minimized.
Some manufacturers recommend draining the tank and system before storage.
In environments with high humidity, this is the best method of preventing water accumulation. Some manufacturers may also recommend treating the fuel with a stabilizer to inhibit the oxidation and subsequent deterioration of the gasoline during storage. Only a few manufacturers may make these recommendations, but it is very important to consult the owners' manual. Even if some manufacturers discourage the use of ethanol-blended fuels for their equipment, it does not mean that they are lower quality fuels. It may simply be that the particular manufacturer has not yet conducted a test program or wants more field experience with these fuels.