When the throttle valve of the 1st chamber is opened, the cam 20, mounted on its axis, presses the lever and acts on the diaphragm of the pump 19 through the spring in the pusher. and 2 cameras.
When the throttle valve of the 1st chamber is closed, fuel from the float chamber is sucked into the cavity of the accelerator pump. Check ball valves close the inlet and outlet channels in series.