An automatic choke system for carburetors

An automatic choke system, comprising: a wax-type temperature sensing section; and an output section which opens a carburetor choke valve according to the heat receiving operation of the temperature detecting section. The temperature detecting portion comprising: a cylindrical housing with a bottom, which is connected to the engine and its high-temperature portion of the bottom point of the engine; a bottomed movable cylinder; stationary piston slidably supported by the movable cylinder and having one end projecting the movable cylinder; and a wax, which is housed in a sealed manner the movable cylinder, such that the movable cylinder and the piston and axially fixed relative to each other. The movable cylinder is fixed at the outer end of the piston which abuts against the inner surface of the bottom portion of the housing slidably received in the state of the housing. The output portion is connected to the movable cylinder. Thus, the rate of opening the choke valve immediately after the start shortly immediate increase in the engine warming-up operation, and when the access to the engine warming-up operation sometimes reduced.