Abstract: A choke for use with a carburetor on an internal combustion engine comprises a housing having an air inlet and an air outlet the air outlet being adapted for communication with the air intake of a carburetor. A valve means within the housing includes a valve member and means biassing the valve member in a direction to block the passage of air between the air inlet and the air outlet of the housing. The valve means is responsive to engine vacuum during starting of the engine to move the valve member in a direction against the biassing means to permit air to enter the carburetor from outside the housing via the air inlet and air outlet thereof.

Abstract: A diaphragm type carburetor comprising a main body portion defining a venturi having an air intake side and an engine outlet side. The carburetor has a throttle shutter mounted within the venturi between the air intake side and the engine outlet side, and a metering chamber supplies fuel into the venturi via a main discharge port. The main discharge port opens into the venturi on the air intake side of the throttle shutter. A monitoring means (FIG. 3) is provided to monitor an engine parameter and an electrically controlled valve means is provided to adjust the fuel flow through the main discharge port into the venturi. The valve means is responsive to an electrical signal generated by the monitoring means in response to the engine parameter.

Abstract: A carburetor comprises a main body portion defining a venturi having an air intake side and an engine outlet side, a throttle shutter mounted within the venturi between the air intake side and the engine outlet side, a fuel chamber for supplying fuel into the venturi via a main discharge port and at least one idle discharge port, the main discharge port opening into the venturi on the air intake side of the throttle shutter, a choke feed passage extending from the fuel chamber to the venturi, the choke feed passage opening into the venturi on the opposite side of the throttle shutter to the main discharge port, and means for selectively opening and closing the choke feed passage.