Carburetor with second choke break

摘要

A carburetor has an induction passage, a fuel circuit and a choke valve positioned at the inlet of the induction passage. A metering rod extends transversely of the induction passage and has a variable diameter end portion projecting into an outlet of the fuel circuit. The metering rod is movable relative to the outlet in response to the choke valve opening and closing to control the quantity of fuel entering the induction passage. An opening force is exerted on the choke valve in response to the vacuum created in the engine, the exertion of this opening force being delayed until after an initial opening force has been exerted on the choke valve. The exertion of the second opening force moves the choke valve from a first position to a second and more fully open position. The variable diameter end portion of the metering rod is inserted into the fuel circuit outlet in response to this second movement of the choke valve whereby the quantity of fuel delivered to the induction passage is varied by an amount necessary to produce a resultant air-fuel mixture whose air-fuel ratio is both sufficient to keep the engine running and reduce emissions produced by the engine.