Metering rod control for an air valve carburetor

Abstract From the Canadian patent

Abstract of the Disclosure, An air valve for a carburetor has its lower end mounted for pivotal movement between open and closed positions relative to the air and fuel mixture conduit and carries a metering rod which extends generally in a horizontal direction. The metering rod has an end extending within a metering orifice of an orifice plate in an opening of the mixture conduit wall. The metering rod is urged by a coiled torsion spring upwardly against the orifice plate. The torsion spring has a small coil with a relatively high spring rate and a large coil with a relatively low spring rate. The large coil continuously urges the rod into engagement with the upper surface of the orifice …