The high speed system controls the fuel-air mixture from part throttle to full throttle range of operation. To maintain a proper mixture ratio a small amount of air is admitted through the well into the discharge jet through the air bleed holes in the discharge jet at a point below the level of fuel in the metering well. The fuel flows from the fuel chamber through the main jet and into the main discharge jet where it is mixed with air admitted by the well vent. This fuel-air mixture is then discharged into the air stream through the main venturi.