Carburetor

In a carburetor including an intake bore having a venturi portion therein, a throttle valve disposed in said intake bore at the downstream side of said venturi portion, a primary nozzle opening to a portion of said intake bore between said throttle valve and said venturi portion, and a secondary nozzle opening to said venturi portion, said primary nozzle and said secondary nozzle being in communication with a float chamber through a primary jet and a secondary jet, respectively;

• an improvement which comprises:
• a slow fuel passage shunting from a portion between said primary nozzle and said primary jet, said slow fuel passage being communicated with an idle port and a by-pass port both of which open to said intake bore in the vicinity of said throttle valve;
• a cup-shaped disposed beneath the level of the fuel in said float chamber and defining therein a downwardly opened space, said primary jet opening to an uppermost portion of the space in said cup-shaped member while said secondary jet opening to an intermediate portion of the space in said cup-shaped member;
• a main fuel tank storing an alcoholic fuel therein and communicating with said float chamber through a float chamber;
• and an auxiliary fuel tank storing gasoline therein and communicating with the space in said cup-shaped member through a metering pump.