Abstract: A system vaporizes fuel for an internal combustion engine. This system has an auxiliary fuel tank connected to the main fuel pump. An auxiliary fuel pump has its intake connected to the auxiliary fuel tank and discharges into an auxiliary fuel line. The auxiliary fuel line passes through a preheater which heats the fuel through heat exchange with exhaust from the engine. The preheated fuel passes to a vaporizer chamber. The vaporizer chamber is electrically heated to vaporize the fuel, which then passes to the carburetor for mixing with air. The system has a bypass line to deliver an increased amount of fuel to the vaporizer chamber if the engine is accelerated. Valves and thermostats enable operation of the engine using conventional liquid fuel until the heat exchanger and vaporizer chamber reach operating temperature.