a fuel supply system for an internal combustion engine operated on gaseous fuels , for example , liquid petroleum gas . the system includes a housing having a chamber for vaporizing liquid gas , including means for heating the vaporizing chamber . also included in the housing is a mixing chamber for mixing the vaporized gas with incoming air for delivery to the intake manifold of an internal combustion engine through a standard carburetor . the fuel supply system includes means for mounting the system on the carburetor , including means for supporting an air filter circumjacent the mixing chamber .