The effect of the adjustment and maintenance of the fuel supply system of the carburetor engine on the vehicle emissions. The oil-type engine fuel supply system forms an appropriate combustible mixture based on the vehicle's driving conditions. The main points of maintenance adjustment are: cleaning and checking each nozzle, the main oil supply hole, the idle oil passage, the main air measuring hole, the idle air measuring hole: installing and checking the adjustment float; If the carburetor is not properly adjusted, the engine exhaust emissions will exceed the standard. For example