Variable venturi carburetor

A variable venturi carburetor having an induction passage communicating with ambient air at one end and adapted to be connected to an engine inlet manifold at the opposite end, the induction passage having a fixed area venturi defined by a fixed area choke, the passage converging upstream of the choke and diverging downstream of the choke, a main fuel passage extending into the induction passage and communicating with a fuel discharge tube which extends axially along the choke, an elongated throttle body supported at its upstream end by engagement with the fuel tube for a sliding movement in the induction passage, a throttle control device arranged for supporting the downstream end of the throttle body for a sliding movement and for displacing the throttle body between an idle speed position and a full throttle position downstream of the idle speed position, the throttle body having a divergent portion merging into a convergent portion, the throttle body in its idle speed position closely fitting the induction passage, displacement of the throttle body towards the full throttle position opening a variable throat between the widest part of the throttle body and the divergent portion of the induction passage, the throttle body having internal passages connecting the fuel tube to the widest part of the throttle body for discharge of fuel into the variable throat, the fuel tube being formed with a number of openings in its wall, the openings being just below the exit of the main fuel passage and communicating with the fixed choke flow area, the openings being sufficiently large that the pressure in the fixed choke flow area determines the flow of fuel in the main fuel passage, the throttle control device comprising a throttle shaft extending across the induction passage and passing between legs formed in the downstream end of the throttle body, and a lever mounted on the throttle shaft within the induction passage for connecting the shaft to the throttle body.