Carbureted engine
The fuel pump is screwed onto the cylinder head. It is actuated via a lever directly from the camshaft. It is not necessary to remove the pump to check it.
Attention! When removing the fuel pump, some fuel may come out. Fuel vapors are poisonous, so ensure that the room is well ventilated. Avoid skin contact with fuel. Wear fuel resistant gloves. Do not work near open flames! Keep a fire extinguisher ready!
Examination
1. Disconnect the fuel hose on the carburetor and connect to a pressure gauge.
2. Disconnect the fuel return hose from the pump and plug the fitting on the pump with a plug. Fasten the plug with a clamp. Plug the fuel return line with a clean bolt.
3. Ask an assistant to start the engine. At the number of revolutions of the starter, read the pressure gauge. Pressure at starter speed should be 2.8-3.5 bar (E1, E3, E5: 2.0-3.0 bar).
4. Remove the pressure gauge and lower the fuel hose into the measuring vessel (beaker).
5. Ask an assistant to start the engine. The idle pump should deliver 800 ml of fuel per minute.
6. Remove the plug, connect the fuel lines and secure with clamps.
7. If the test values are not correct, the pump is defective and must be replaced.
Removing
1. Loosen hose clamps and disconnect fuel hoses -1- and -2-. Plug the hoses with suitable clean bolts. Mark hoses with adhesive tape.
Attention! When disconnecting fuel lines, place a rag to collect escaping fuel.
2. To unscrew bolts of fastening and to remove the fuel pump -3-, linings and an insulator.
Installation
1. Carefully free the sealing surface on the cylinder head and the insulator from seal residues using a scraper.
2. Install the fuel pump with 2 new gaskets and insulator and tighten the mounting bolts with force 25 Nm.
3. Connect the fuel lines according to the marking and secure with hose clamps.
4. Start the engine and check the tightness of the fuel pump and connections.