Vaporizer is an important device in the gasoline fuel supply system. It is used to volatilize gasoline and form a uniform combustible mixture with air. It is often composed of floats, float chambers, needle valves, pipes, fuel injection pipes and measuring holes. The gasoline sent from the gasoline pump enters the float chamber from the inlet. The float chamber has a needle valve connected to the float to control the oil level to maintain a certain oil level. The gasoline enters the fuel injection pipe from the float chamber through the measuring hole. The fuel injection pipe outlet is about 3 to 5 mm higher than the oil level of the float chamber to prevent gasoline from overflowing. When the piston moves down and the intake valve opens, air from the air filter enters through the inlet and flows through the choke valve into the vaporizer. The air flows through the throat and the negative pressure is formed due to the sudden increase of the flow rate. The gasoline is ejected from the fuel injection pipe under the pressure difference, and is blown into a number of fine oil droplets by the high-speed air. The oil mist evaporates along the way and mixes with the air to form a uniform combustible mixture and then enters the cylinder. The amount of gasoline ejected from the fuel injection pipe is determined by the diameter of the orifice, and the amount of combustible mixture entering the cylinder is controlled by a throttle valve (commonly known as "throttle"). According to the direction of air flow, there are two types of upper suction type and lower suction type. According to the structure, there are single injection manifold vaporizers and multiple injector vaporizers. The simple vaporizer can only meet the needs of small gasoline engines with very stable individual loads. For most gasoline engines with frequent workload changes, a carburetor equipped with a series of auxiliary devices such as starting, idle (ie idling), enrichment, acceleration, etc., must be used to automatically change the flammability according to various load changes and different working conditions. The concentration of the mixture to ensure good engine performance and low fuel consumption.