Abstract: A composite control valve is constructed by a valve housing, first and second diaphragms mounted to the valve housing and disposed to be opposed to each other, a negative pressure working chamber defined between the first and second diaphragms to communicate with a negative pressure generating section in an engine, a first control valve adapted to be opened and closed by advancing and returning of the first diaphragm, and a second control valve adapted to be opened and closed by advancing and returning of the second diaphragm. The first control valve is incorporated into an air vent system for a fuel tank, and the second control valve is incorporated into a fuel passage system extending from the fuel tank to a fuel supply section in the engine.

Abstract: A composite control valve is constructed by a valve housing, first and second diaphragms mounted to the valve housing and disposed to be opposed to each other, a negative pressure working chamber defined between the first and second diaphragms to communicate with a negative pressure generating section in an engine, a first control valve adapted to be opened and closed by advancing and returning of the first diaphragm, and a second control valve adapted to be opened and closed by advancing and returning of the second diaphragm. The first control valve is incorporated into an air vent system for a fuel tank, and the second control valve is incorporated into a fuel passage system extending from the fuel tank to a fuel supply section in the engine.

Abstract: A down-drafting constant vacuum pressure type diaphragm carburettor includes a carburettor body with an induction passage, a throttle valve, a Venturi portion variable of open area. A vacuum actuated valve is arranged at upstream side of the throttle valve across the induction passage and extending in horizontal direction from one side to the other side, and controls an open area of a Venturi portion depending upon a vacuum pressure generated in the Venturi portion. A jet needle is mounted on the vacuum actuated valve. A fuel control system including a diaphragm arranged between a recessed portion of the carburettor body and a cover covering for defining a regulator chamber at the side of the recessed portion and an atmospheric pressure chamber at the side of the cover, and a valve seat. The diaphragm is arranged at lower side of a longitudinal axis of the jet needle.

Abstract: A carburetor having a main intake passage for a lean mixture and an auxiliary intake passage for a rich mixture is provided with a choke valve in each passage. A control mechanism for operating the two choke valves includes a lost-motion connection so that the main choke valve is at the first to be moved toward closed position, for cold starting of the engine. For colder temperatures, both choke valves are moved toward closed position, and for very cold starting conditions, both choke valves are moved to fully closed position. The control mechanism may be manually operated or it may be automatic under the control of a bimetal element. When the engine on being started reaches a state of complete firing, with stable RPM, both choke valves are opened to predetermined pull-down angles.