Sea Foam ??

For storage pursposes, the small recommended dose per gallon of fuel is acceptable. The main components of seafoam are naptha and alcohol's The naptha helps reduce the volitility of the fuel (to reduce the ability of the fuel to evaporate the "lighter" hydrocarbons off and "gum") and the alcohol absorbs the water out of the fuel blend which causes increased oxidation of the gasoline.

You should, however, not be putting any more than the recommended dose in the fuel tank/gas can. Alcohol in small doses is perfectly fine and won't hurt a thing to run through the carburetor but in larger doses it will "turn" the rubber inside the carb and let the float needle leak by letting the carburetor flood.