The function of the petrol pump is to suck the petrol out of the petrol tank and to give the petrol tank some pressure so that it overcomes the resistance of the pipe and enters the carburetor's float chamber or the electronically controlled injection engine via the pipe and the petrol filter In the fuel supply guide. Common faults of the gasoline pump: insufficient fuel supply for the fuel pump The fuel supply for the fuel pump depends on the stroke of the pump membrane. When the stroke is large, the amount of pump oil should be large. However, the fuel pump needs a small amount of pump oil, Gasoline pump oil will inevitably more, if the engine fuel consumption, but the actual fuel supply is less, this situation is the fuel pump fuel supply is insufficient, there will be a carburetor float chamber oil level lower engine power shortage. Fault reasons: 1) Gas pump and shaft box by the seal at the place too thick. 2) Pump membrane rupture or pump film and pump housing seal at the lax. 3) out of the valve stuck or bad seal. 4) severe arm wear to reduce the pump membrane stroke. 5) The pipeline from the fuel tank to the gasoline pump is poor, or the pump membrane spring is over.