Throttle positioner

A throttle positioner to ensure a predetermined minimum opening for a throttle valve in an internal combustion engine when the engine is abruptly decelerated from a relatively high-speed condition, comprising a throttle arm connected with a shaft of the throttle valve, a member movable between a first position where it traverses a trace of movement of the throttle arm and a second position where it is held out of said trace, a diaphragm means adapted to operate with the intake vacuum of the engine so as to bias said member toward said second position when the intake vacuum is applied thereto, a port which opens to an intake passage of the engine at a position which is downstream of the throttle valve when it is closed until said throttle arm engages said movable member, and is upstream of the throttle valve when it is opened with said throttle arm not being in engagement with said movable member, and a conduit means which connects said port with said diaphragm means, said port and conduit means including a buffering air chamber and a parallel assembly of a check valve and a constricting orifice means disposed therein, said check valve being oriented to allow fluid to flow only toward said diaphragm means.