If you don't cycle your fuel through the tank every two months, it starts an oxidation process and will turn into varnish over time. This varnish can clog your fuel lines and carburetor jets, and rust can start to form in the fuel tank. Griot's Garage Fuel Preservative prevents both the deterioration of fuels and fuel system corrosion. Great for automobiles, boats and lawn mowers. Start protecting your investment today! One ounce protects three gallons of any type of fuel for two years. Meets and exceeds military specification G-3056D. Accurate, safe and easy to dispense. 16 ounce bottle treats 48 gallons.