Abstract: Hot water is transmitted from an automobile's cooling system to a fuel vaporizer wherein it is utilized to heat gasoline to a vapor state. Air is drawn into the fuel vaporizer utilizing carburetor vacuum and is added to the vapor and drawn into the carburetor. Vaporized fuel and outside air are mixed in a separate dry vapor section within the vaporizer and the amount of air allowed to enter the fuel vaporizer is controlled utilizing a valve system. In this manner, the fuel-air vapor is more efficiently burned in the engine and improved gas mileage is achieved.