US Patent 7104253 Stratified scavenging carburetor

In one presently preferred embodiment a stratified scavenging carburetor has a scavenging air passage with an air control valve and a fuel and air mixing passage with a throttle control valve, and a lost motion coupling associated with the valves to delay opening of the closed air valve until the throttle valve has partially opened from its idle position to an off idle position and preferably thereafter to open the air valve in phased relationship with the throttle valve so that the valves become wide open at substantially the same time. Preferably the coupling has reels associated with the valve and connected by a flexible cord.