Pic. 50. Carburetor starter:
1 - diaphragm; 2 - adjusting screw; 3 - diaphragm rod; 4 - air damper control lever; 4.1 - lower profile of the groove of the lever 4 to limit the maximum opening of the air damper; 4.2 - the upper profile of the groove, which provides mechanical opening of the air damper; 4.3 - the edge of the lever 4 to ensure the starting clearance of the throttle valve of the first chamber; 5 - air damper; 6 - air damper lever; 7 - air damper return spring; 8 - draft of the handle of the air damper drive; 9 - adjusting screw stopper; 10 - adjusting screw for slightly opening the throttle valve of the first chamber; 11 - throttle control lever; 12 - throttle valve of the first chamber.
When the air damper control lever 4 is turned counterclockwise, the expanding groove between the inner profiles 4.1 and 4.2 releases the pin of the air damper lever 6 and the damper will be held in the closed position by the return spring 7. At the same time, due to a significant vacuum under the throttle valve and in the mixing chamber, the main metering system, the idle system and the transition system of the first chamber will work, preparing a rich combustible mixture.
The axis of the air damper is displaced, therefore, after starting and increasing the engine speed, the damper will be slightly opened by the air flow, stretching the spring 7, which will provide some depletion of the mixture.
An increase in vacuum in the under-throttle space affects the diaphragm Y, as a result of which the air damper is forcibly opened with the help of rod 3. Adjusting screw 2 allows you to adjust the amount of this opening. Its maximum value when starting and warming up the engine depends on the intermediate positions of the air damper control lever 4, i.e., on the width of the groove of this lever, and on the position of the adjusting screw 2.
As the engine warms up, the choke control handle is gradually moved forward, and lever 4 with profile 4.2 opens the choke.