Abstract: Initially the engine operates normally with the exhaust gases preheating the air from the air cleaner intake, said air then being pressurized prior to it entering the carburetor. As the coolant temperature increases, heated coolant flows through a double heater coil within a chamber in which gasoline is contained. This vaporizes the gasoline and increases its pressure within the chamber until a predetermined pressure is reached which actuates a pressure switch controlling a solenoid valve which in turn by-passes the carburetor and allows pressurized fuel vapor to mix with preheated air under pressure thus operating the internal combustion engine on the cracked fuel and hot air mixture. When the engine is shut down the system returns to the original condition ready for the next starting cycle.