Starting a cold engine
The air damper is closed due to the operation of the element that expands under the influence of heat. During start-up, the engine vacuum causes intense fuel suction with a reduced amount of air. After starting the engine, the vacuum starter, acting on the traction mechanism, causes the air damper to slightly open. Throttle valve slightly open (additional opening) so as to obtain idling with increased engine speed.
During engine warm-up, the heat-expanding element is heated by the coolant and has less effect on the starter.
Idling
The throttle valve is closed, fuel enters through the main fuel jet and reaches the idle fuel jet, where it forms a mixture with air. The amount of mixture supplied can be adjusted with the mixture composition screw.
Special slot (opening of the so-called smooth transition) allows to avoid sudden depletion of the mixture during the opening of the throttle valve 1 of the chamber.
In chamber 2, the smooth transition system feeds a special circuit. A tube equipped with a jet is immersed in a float chamber. At its end in the cover, a special air jet supplies air, and the mixture reaches the place where the throttle valve is slightly opened. The second chamber does not have an idle system.
Normal operation
Fuel is supplied through a needle valve to a float chamber in which a float mounted on the axle controls the opening of the needle valve to maintain a constant fuel level. Fuel leaves the float chamber through the main fuel jet and is fed into the well. The first chamber is open, the fuel is sucked in and mixed with air in the emulsion tubes. The mixture is fed to the diffuser where spraying takes place. The same process occurs in the second chamber when its throttle valve is open.
Acceleration
During the opening of the throttle valve of the first chamber, the cam mounted on its axis pushes the lever, which acts by means of a pusher equipped with a shock-absorbing spring on the pump diaphragm. fuel injected (simultaneously in two chambers) through a sprayer. During the closing of the throttle valve, fuel is sucked into the pump chamber from the float chamber. Ball check valves separate the suction and pumping circuits.