Abstract: In the device provided, air/fuel mixture for an internal combustion engine passes through a conventional carburetor where vaporized fuel and aspirated liquid fuel droplets are mixed witth the air. The device comprises a conduit for conveying the carbureted mixture from the carburetor to an intake manifold. The conduit has an upper opening and a lower opening. A rotatable turbulence producing means, such as a freely rotatable impeller, is disposed in the conduit near the lower opening. The rotatable means rotates about a vertical axis by passage of the carbureted air/fuel mixture therethrough and turbulence of the mixture is produced. Liquid fuel droplets are engaged by a collector and vaporizing means which is disposed in the conduit near the upper opening and above the rotatable means. The collector and vaporizing means has a substantially enclosed central portion disposed axially above the vertical axis of the rotatable and outer portions slopingly connected to and disposed above the central portion.