Control means for secondary throttle

Claim 1

In a multiple stage carburetor for an internal combustion engine, a primary mixture conduit having a primary throttle valve therein and a secondary mixture conduit having a secondary throttle valve therein, primary and secondary throttle shafts on which the primary and secondary throttle valves are mounted, a linkage releasably connecting the primary and secondary throttle shafts for rotation including a latch member for the linkage movable to a latched position to connect the linkage for sequential opening of the secondary throttle valve; the improvement comprising a diaphragm motor operatively connected to the latch member to move the latch member to a latched position, a vacuum line connected to the diaphragm motor and in fluid communication with the intake manifold vacuum, an air bleed in the vacuum line including an air bleed valve member, and a temperature responsive bimetallic element operatively connected to the air bleed valve member to control the amount of air bled into the vacuum line, said bimetallic element responsive to a predetermined high engine operating temperature and being actuated upon reaching the desired engine operating temperature to increase the amount of air bled into the vacuum line and effect movement of the latch member to latched position to permit opening of the secondary throttle valve.