Abstract: The disclosure embraces a fuel feed and charge forming apparatus wherein the apparatus is of comparatively small size particularly for use with chain saws and other motor driven tools to effect the reduction in weight. The charge forming apparatus embodies a body construction providing external support members to resist creep and bolt-torque deformation, as well as providing a heat sink-heat transfer means. A valve seat construction for shape retention is also provided to inhibit fuel metering distortions caused by deformation of valve seats by carburetor body creep.

Abstract: A slide valve carburetor includes an idle fuel system to deliver fuel to the central downstream portion of the main air induction passage. The idle fuel delivery system is sequentially occluded as the driven device attains full-throttle operation, and can be designed to allow passage of supplementary fuel at full or partial throttle operation.

Abstract: An automatic fuel control valve useful with, rotary, as well as 2-stroke cycle and 4-stroke cycle reciprocating internal combustion engines employs a rubber-like check valve and a porous plug in combination with a chamber for averaging recurrent vacuum pulses from the engine, in which the resulting average pressure is applied to maintain a fuel valve in the open condition while the engine is running and to permit the valve to close when the engine is not running.