Abstract: In a device of the type including a throttle operating wire secured to a rotatable member operatively connected with the throttle valve, the wire is slidably covered by a tubular flexible guide having an axially extensible portion and furnished with spring means for biasing the guide portion in an extending direction. The flexible wire guide is held fixed at the opposite ends, is flexed therebetween, and is axially contractible against the spring bias when the tension of the wire exceeds a predetermined level so that stop means provided to limit the extent of closing movement of the throttle valve is kept free from any deformation as resulting from an excessive wire tension. This enables the throttle valve to assume the exact idling position and ensures desired engine idling.