Patent ID: 8608136

Claim:
A dust seal structure for a valve stem in a rotary throttle valve carburetor, having a cylindrical throttle valve provided with a metering needle and a throttle through-hole, and disposed perpendicularly with respect to an air intake passage in a carburetor main body; and a fuel nozzle disposed on the central axis of the throttle valve, made to open into the throttle through-hole, and provided with the metering needle inserted therein, so that the valve stem of the throttle valve, which protrudes at one end from the shaft hole formed in the cover body of the valve hole in the carburetor body, is caused to rotate in accordance with the operation of the accelerator pedal, whereby the throttle valve moves in the direction of a central axis thereof while rotating as a whole, and controls an airflow rate and a fuel flow rate; wherein a dust-proof member composed of a sealing ring is fitted within the shaft hole formed in the body between the valve stem and the shaft hole.