Improves engine efficiency & removes internal carbon deposits from marine engines. Sierra combustion cleaner fuel additive Dissolves gum and varnish build up in fuel system Frees sticky piston rings Displaces moisture in fuel Can be used as a fuel stabilizer for winter storage For use in both 2-cycle & 4-stroke marine engines Mix 1 to 2 ounces to every one gallon of gasoline 12 ounce bottle