A variable venturi carburetor in which a biasing spring urges a metering needle to contact the metering jet during low air-intake operating conditions and including an expanded portion formed at the front end of the metering needle which is loosely contained in a large bore portion of a well during low air-intake operating conditions and which engages a small bore portion of the well during high air intake operating conditions to center the metering needle in the metering jet for maintaining bleed sensitivity constant while the amount of bleed air varies.