1. Before checking the pump, first check that the piping is free and that the filter is not clogged.
2. Connect a pressure gauge using a suitable coupler between the pump and the carburetor, as shown in the illustration below. Disconnect the fuel return hose from the pump to the tank, plug the pump nozzle. For example, you can insert a bolt of suitable diameter into the end of the hose.
Elements for checking the supply pressure of the fuel pump
1 - to the carburetor; 2 - outlet hose; 3 - a bolt inserted for sealing; 4 - inlet hose; 5 - from the fuel filter; 6 - pressure gauge
3. Run the engine at various speeds and read the pressure gauge. The pressure should be between 0.20-0.34 bar.
4. If the value is not correct, remove the pump and check it.
Fuel pump repair
The fuel pump is a wear part and cannot be dismantled because the top cover is pressed onto the bottom of the pump during manufacture. If the test values do not correspond to the required values, a new pump must be installed. The pump can be briefly tested by plugging the inlet and outlet hoses and pressing the pump lever. The suction noise of the pump can tell if the pump is producing suction and discharge pressure. However, the test does not tell if the pressure pump is working properly.