Abstract: A carburetor having a choke valve has an open-close valve sliding reciprocatingly inside a valve hole partway along a bypass air passage. The open-close valve, pressed by urging member, slides according to a rotation angle of a choke valve shaft while a distal end side continuously contacts a side face of the shaft. A projecting part, urged by a coil spring, projects from a distal end of a body. The urging member includes a temperature-sensitive material that expands at or above a prescribed temperature. When the choke valve is closed and the ambient temperature is less than the prescribed temperature, the bypass air passage enters a closed state while the body remains in a closed-valve position; and when the ambient temperature is at or above the prescribed temperature, the urging member elongates and the body enters an open-valve position, and the bypass air passage enters an open state.

Abstract: A carburetor control system includes: a governor device that is coupled to a throttle lever, opens a throttle valve when an operation of an engine is stopped, and opens or closes the throttle valve in accordance with a rotational number of the engine when the engine is in operation; a choke return spring urging a choke lever in a direction to close a choke valve; and an automatic choke device opening the choke valve in accordance with an increase in temperature of the engine. In the carburetor control system, the throttle lever is provided with a drive arm pivoting the choke lever, during a cold operation of the engine, to a position where the choke valve is at an intermediate degree of opening in operative connection with the throttle lever being pivoted by the governor device to a position where the throttle valve is at a degree of opening for idling or a position in a vicinity thereof.

Abstract: In at least some embodiments, the present invention relates to an automatic choke system for use in an engine having a muffler and a choking mechanism that are located remotely apart from one another. The system includes a thermally responsive device, at least one component that serves to connect, at least in part, the device to the choking mechanism, and a further mechanism for conveying heat from the muffler to the device. Additionally, the system in at least one embodiment includes at least one of: (a) a pipe for conveying a fluid from a first location proximate the muffler to a second location proximate the device, the pipe being comprised within the further mechanism; and (b) a rotatable axle that spans a majority of a distance between the first location and a third location that is proximate the choking mechanism, the axle being comprised within the at least one component.

Abstract: A carburetor automatic control system in an engine includes, a temperature-sensitive operating device for operating a choke valve so that the choke valve is opened with a temperature increase of the engine and a governor for opening and closing a throttle valve to maintain a preset rotational speed of the engine. The governor device includes, a stepping motor opening and closing the throttle valve over a range from an idling opening degree to a fully opening degree, and an electronic control unit driving the stepping motor so that the rotational speed of the engine is maintained the preset speed. A relief mechanism is interposed between the choke valve and the temperature-sensitive operating device, the relief mechanism opening the choke valve in response to an intake vacuum pressure within the intake passage when the engine is in a cold state and the choke valve is in a fully closed state.

Abstract: A carburetor valve control system for stabilizing engine warm-up operating conditions by automatically controlling the degree of opening of a throttle valve so as to be larger than a normal degree of opening for idling, without carrying out a special operation of appropriately strengthening the spring force of a governor spring. The carburetor throttle valve control system includes a throttle lever and a governor system coupled to the throttle lever. A choke return spring is connected to a choke lever, the choke return spring urging the choke lever to a choke valve closing side. An automatic choke system is disposed so as to face the choke lever. A throttle valve closure restricting member is provided between the throttle lever and the choke lever. During engine warming-up, when the spring force of a governor spring is adjusted to zero or a minimum, the choke lever restricts closing of the throttle valve via the throttle lever by means of the spring force of the choke return spring.

Abstract: An internal combustion engine including a carburetor. The internal combustion engine includes a choke valve disposed within the carburetor, and a choke lever interconnected with the choke valve for movement with the choke valve. The engine also includes a throttle valve disposed within the carburetor and a throttle lever interconnected with the throttle valve for movement therewith. An intermediate lever is disposed between the throttle lever and the choke lever for movement with the choke and throttle levers. In one embodiment, the engine includes a connecting link coupled between the choke and intermediate levers, the connecting link movable with movement of the choke lever such that movement of the choke lever is translated into movement of the intermediate lever.

Abstract: A device for controlling a choke valve of a carburetor for an engine includes: a choke closed state hold device for holding, in a closing position, a choke lever urged by a spring in a direction for opening the choke valve, when the choke lever is turned to the closing position, the choke closed state hold device releasing the choke lever from the held state by a throttle operation thereafter performed; a control lever which turns between a low-temperature position and a high-temperature position, and which at its low-temperature position limits the position of the choke lever released from the choke closed state hold device to an intermediate position and at its high-temperature position limits the position of the choke lever to an opening position; a first control spring which urges the control lever toward the low-temperature position; and a second control spring which is made of a shape memory alloy, and which turns the control lever to the high-temperature position when the engine temperature reaches a p

Abstract: A choke valve control system includes a choke-operating lever for opening and closing a choke valve of a carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion of the valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor. In this choke valve control system, the damper includes a damper housing, a rotor, and a damper oil which is accommodated in a sealed manner in the damper housing and applies a viscosity resistance to the rotation of the rotor, which resistance increases as the viscosity increases with decreasing temperature.

Abstract: A variable venturi carburetor for a combustion engine has an uprighted cup-shaped piston head which forms an integral part of a venturi within a fuel-and-air mixing passage carried by a carburetor body, and a needle that projects rigidly downward from the head into a fuel feed passage. The position of the piston head controls air flow by adjusting the air flow cross-section of the variable venturi, and the needle simultaneously controls fuel flow into the fuel-and-air mixing passage at the venturi via obstruction of the fuel feed passage. The piston head and needle move in unison by a flexible diaphragm engaged to and disposed above the head. An atmospheric chamber is defined below the diaphragm and a vacuum chamber is defined generally above the diaphragm. A vacuum passage extends through the bottom of the head communicating between the fuel-and-air mixing passage at the venturi and the vacuum chamber.