POSITION CONTROLLER OF CARBURETOR THROTTLE VALVE

PURPOSE:To simplify the structure and to improve starting operating by providing a first idle opening setter integrally on an idling speed controller employing a negative pressure servo motor. CONSTITUTION:A push rod 11 provided on a negative pressure servo motor 2 is contacted against a lever 12 secured to a throttle valve 1. The servo motor 2 is provided with a second negative pressure chamber 15 communicating through a path 18 with a drive diaphragm chamber 9, signal diaphragm 4A, etc. Under stoppage of an engine, negative pressur will not function into each chamber of motor 2 and the throttle valve 1 is at the position where the return torque of restrictor 1 and reaction of spring 19 are balanced with reaction of springs 21, 22 thus to determine the first idle opening. Under operation, the negative pressure in second negative pressure chamber 15 will exceed over that in said chamber 9 to separate the positioning diaphragm 16 from diaphragm plate 20 thus to perform conventional idle control.