Berryman B-12 Chemtool Fuel Injector Cleaner (part #0116, 0101, 0105) will be most effective when used, as-supplied. We advise against mixing it with more than 1 part gasoline. Dwell time requirements vary, but the tank should soak at least a couple hours and can go overnight, if desired. At some point, the product will become saturated with gum and varnish, the mixture will have to be drained, and the process will need to be repeated until the tank is completely clean.