Carburetor

A carburetor having a choke valve rotatable between closed and open positions, a rotatable choke pulldown lever connected to the choke valve for rotating the same, a throttle valve biased towards a closed position and rotatable between closed and open positions, a throttle lever operably fixed for rotation with the throttle valve and having a stop screw thereon, a rotatable fast idle cam having first and second circumferentially contiguous radial face type steps thereon of lessening radial extent adapted in first and second rotative positions of the cam, respectively, to project into the path of movement of the stop screw in a throttle valve closing direction to stop the throttle valve rotation in a different open position as a function of the step engaged by the stop screw, a first link connected to the pulldown lever for moving the pulldown lever to open the choke valve, a second link connected to the cam for rotating the cam to disengage the first cam step from the stop screw and engage the second cam step with the stop screw, a vacuum controlled servo, and control means connecting both the first and second links to the servo for controlled actuation of the pulldown lever and movement of the cam, the control means including an actuating rod reciprocable in opposite directions, the rod having a first elongated slot slidably receiving one end of the first link therein in a lost motion type manner, the rod having a second elongated slot slidably receiving therein one end of the second link in a lost motion type manner, the first link end abutting an end of the first slot when the choke valve is in a closed position, the second link end being spaced from the ends of the second slot when the choke valve is closed whereby actuation of the rod in one direction first moves the first link to open the choke valve and subsequently moves the second link to rotate the cam, the servo including a housing, a movable fluid pressure actuated diaphragm in the housing with the housing defining a vacuum chamber and an ambient air vent chamber, means connecting the diaphragm to the rod for movement thereof, spring means biasing the diaphragm and rod in a choke valve closing direction, conduit means connecting a source of engine vacuum to the vacuum chamber, and means to control the movement of the diaphragm to provide a dual stage movement of the rod including vacuum metering means to control the flow of vacuum to act on the diaphragm.