Idle By-Pass System
Air brought into carburetor during idling passes through a by-pass drilling, by-passing throttle valve. Bore of by-pass drilling can be altered in size by adjusting by-pass screw, depending upon fuel requirements of engine. Fuel for idling passes through main jet to pilot jet cutoff valve. With ignition on, the pilot jet cutoff valve opens, allowing fuel to pass idle drillings. Fuel is metered through pilot jet and auxiliary fuel jet. Metered fuel is mixed with air from metered air holes. A small portion of this air/fuel mixture passes as an emulsion through idle drilling from pilot jet directly into by-pass bore. The main portion of air/fuel mixture passes through idle drilling from auxiliary fuel jet and is metered by volume control screw to opening below throttle valve.