Startron is an enzyme fuel treatment. Stabilizes gasoline for up to 2 years. Cures ethanol problems. Rejuvenates old fuel. Cleans valves, and injectors. Removes gum and varnish. Helps prevent phase separation. Safe for all 2 and 4 cycle engines. Overdosing is NOT harmful. 1 gal treats up to 2,048 gallons of fuel.