Aspen 4 is an oil-free alkylate gasoline that is suitable for four-stroke engines of lawn mowers, rotary cultivators, snow blowers, motorboats and other equipment. Conventional gasoline contains ethanol, which attracts moisture and can cause engine failure. Aspen alkylate gasoline does not contain ethanol, so it is ideal for use, for example, in the marine environment. To use Aspen alkylate gasoline in your two-stroke outboard engine, simply mix Aspen 4 gasoline with outboard oil. To reduce the impact on the environment, choose a biodegradable oil.