Membrane carburetor for manually started internal combustion engine

摘要

The membrane carburetor is for a hand started internal combustion engine, e.g. for a chain saw. It has a main fuel jet (19) into the venturi section of the inlet manifold and an idling jet (20) input downstream of the venturi and downstream of the throttle valve (15). A choke valve (11) upstream of the venturi assumes the same setting for both cold and hot starting. The valve has a preset bypass flow formed by either a loose fit inside the inlet manifold, or by apertures in the valve flap. The apertures provide sufficient air flow to enable the engine to start and idle. The choke valve is opened by the engine suction for operation above idling speed.