Today, all transport: cars, motorcycles, airplanes use four-stroke engines, i.e. piston internal combustion engines, where the working process in each cylinder occurs in two crankshaft revolutions (4 piston strokes).
Engine idle speed can be unstable due to a number of factors. It all depends on the brand of the car. The cause of a malfunction of the engine at idle speed can be not only the carburetor, but, for example, a system that affects the vacuum value in the intake manifold of the engine. cameras. The source may be if it gets stuck open due to dirt on the diffuser walls. The throttle valve of the second chamber opens automatically by means of a vacuum drive when the engine reaches a certain speed (about 3500 rpm). At the moment of opening the damper, the transition system of the second chamber comes into operation. If the nozzles or channels of this system are clogged in the carburetor, then a sharp short-term drop in engine speed occurs. The transitional system operates at a small angle of rotation of the damper, therefore, upon further opening of the throttle, the fuel immediately enters the second chamber without entering the transitional system. To eliminate this drawback, it is necessary to flush the carburetor. If, with a sharp release of gas, the speed drops until the engine stops completely, then the idle system should be repaired. A steady return to a constant idle speed of about 700-800 rpm is one of the tests of his system. Another reason for this phenomenon is a malfunction of the EPHH control unit. When switching the speed from second to third gear, i.e. at medium speed (3000-3500 rpm), the secondary carburetor chamber is switched on. If there is a delay in its inclusion, then the mixture is depleted, and the acceleration of the car will be zero. To eliminate this problem, you can remove the spring from the pneumatic actuator of the secondary chamber. After that, the dynamics will return to normal, elasticity will increase, i.e. downshifts will need to be done less frequently.
