Fuel through the needle valve 1 is fed into the float chamber, in which the float 2 pivotally mounted on the axis maintains a constant fuel level in the chamber.
From the float chamber, fuel enters through the main fuel jet 3 into the emulsion well. When the throttle valve of the 1st chamber is open, a vacuum is formed in its atomizer, under the influence of which the fuel in the emulsion well rises and mixes with the air leaving the emulsion tube hole, made integral with the main air jet 4. Through the atomizer 5, the fuel-air emulsion enters into the diffusers and then into the mixing chamber of the carburetor.
When the throttle valve of the 2nd chamber is open, the operation of the main dosing system of the 2nd chamber is similar.
The throttle valve of the 2nd chamber opens when moving under the action of a vacuum of the diaphragm of the pneumatic actuator 24, which is connected by a rod to the throttle valve 10 of the 2nd chamber. Due to the presence of a mechanical interlock, the throttle valve of the 2nd chamber can only be opened when the throttle valve of the 1st chamber is open and the engine is warm.