Rotary throttle valve carburetor

A rotary throttle valve carburetor, comprising:

• a body having a fuel and air mixing passage;
• a throttle valve carried by the body for movement between idle and wide open positions, having a valve bore that is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from its idle position toward its wide open position;
• a fuel metering needle depending into the valve bore, and responsive to movement of the throttle valve for movement relative to the body in response to movement of the throttle valve;
• and
• a fuel nozzle projecting into the valve bore, communicated with a supply of fuel and operably associated with the fuel metering needle, the fuel nozzle having a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and including a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to movement of the throttle valve toward its wide open position to at least in part control fuel flow from the fuel supply, through the fuel nozzle and into the fuel and air mixing passage.