Disclosed herein is a carburetor including a member defining an air induction passage including a downstream portion, an upstream portion, and a venturi located between the downstream portion and the upstream portion, a member defining a fuel chamber, a fuel well located in the air induction passage defining member, extending in the fuel chamber, and communicating with the fuel chamber, a high speed nozzle located in the fuel well and communicating with the venturi, and an enrichment fuel pump including a cover fixed to the fuel chamber defining member, a diaphragm located between the cover and the fuel chamber defining member and defining a fuel pumping chamber and a variable pressure chamber, a duct communicating between the variable pressure chamber and the downstream portion of the air induction passage downstream of the throttle valve, an inlet conduit communicating between the fuel chamber and the fuel pumping chamber and including an inlet check valve permitting in-flow into the fuel pumping chamber and preventing out-flow therefrom, and an outlet conduit communicating between the fuel pumping chamber and the fuel well and including an outlet check valve permitting out-flow from the fuel pumping chamber and preventing in-flow thereto.