Disclosed herein is a carburetor including a housing having a throat, means for supplying fuel to the throat intermediate its opposite ends, the fuel supplying means including a tube extending into the throat and including a plurality of fuel supply openings spaced along its length. A pivotable throttle member is positioned in the throat intermediate its opposite ends and is pivotable between a fluid flow restricting position and an open position. The pivotable throttle member includes a cam surface. The carburetor is also constructed such that an increased number of the openings supply fuel to the throat as the throttle member pivots from a fluid flow restricting position to an open position and the openings are closed as the throttle member pivots from an open position to a fluid flow restricting position. This is accomplished by a sleeve surrounding the tube and supported for slidable movement on the tube, and a cam follower engaging the cam surface, the cam follower carrying the sleeve whereby the sleeve is slideable on the tube in response to movement of the cam surface with respect to the cam follower.