ABSRACTA new rotary type carburetor was developed for a gasoline engine. It has a rotor which feeds fuel into an engine proportionally to the inlet air flowrate. Comparing with a conventional venturi type carburetor it was simple in design with less parts. The rotary type carburetor was tested on an engine dynamometer for the various engine operating conditions. During acceleration and deceleration, the rotary type carburetor could not supply the fuel adequately, resulted in unstable engine operation. Under steady running conditions the rotary type carburetor was superior to venturi type in power and fuel economy. It was concluded from the experimental study that the rotary type carburetor is more suitable for the steady running gasoline engines especially at high speeds.