Carburetor 1B1 — design description

The downdraft carburetor fell out of aluminum. The float and mixing chambers are in a single housing. The idle shut-off valve after turning off the ignition blocks the access of the idle mixture to the mixing chamber. If the valve is faulty, the engine will not start. The mixture enricher is located on the side during uniform movement. A curved washer connected by a lever to the throttle shaft drives the accelerator pump. After adjusting the amount of fuel injected, the bent washer is fixed with a locking screw and fits snugly against the pump cover. The carburettor cap contains jets and emulsion tubes, a float with a needle valve, a connecting tube for supplying fuel, an accelerator pump control lever, a starting choke with a roller, a riser tube for enriching the mixture at full power and an exhaust tube. in an emulsion tube. Below is the main jet, above is the combined air/fuel jet for base idle and the combined air/fuel jet for the auxiliary mixture. The air adjustment jet with a mixing tube is pressed into the emulsion tube from above and is located above the main jet. Acting on the start cable manually, it is possible to set the starting air damper, the starting roller and the bimetallic spring, the drive lever with a lever system, the throttle valve through the start lever, through the bent washer, the idle lever, with an adjusting screw, to the cold start position. After turning on the ignition, in the first phase of a cold start, as a result of turning the engine with a starter, under the throttle, but at the exit of the idle mixture, bypass holes, as well as in the mixing chamber under the start damper, a low pressure area is formed. The vacuum causes the flow of fuel. To avoid over-enrichment, the axis of the starting damper is shifted from the middle of the damper in such a way that the low pressure acting in the mixing chamber allows the damper to open slightly, overcoming the resistance of the bimetallic spring, strictly regulating the amount of air in the mixture.