Removal, installation and check of the mechanical fuel pump

Carbureted engine

The mechanical fuel pump is located on the left side of the cylinder block and is driven through an intermediate shaft. To check the fuel pump, it must be removed.

Caution: When removing the fuel tank, fuel may spill. Gasoline and its vapors are poisonous and flammable, so ensure that the workplace is well ventilated. Avoid getting fuel on the skin. Wear fuel resistant gloves. No open flame, fire hazard! Prepare a fire extinguisher.

Withdrawal

Disconnect ground wire (-) battery.

Caution: Disconnecting the battery will erase the contents of the electronic memories, such as engine trouble codes or radio codes. Before switching off, also read the instructions in chapter "Removing and installing the battery".

Remove air filter, see next chapter.

Loosen the fastening clamps and disconnect the fuel hoses. Seal the hoses with clean bolts of the correct diameter. Mark the fuel lines with adhesive tape.

Attention: Before disconnecting the fuel lines, place a rag underneath to collect the spilled fuel.

Attention: If the hoses are fastened with terminal clamps, they should be cut and, during assembly, clamps tightened with a screw should be installed instead.

Unscrew the 2 screws securing the fuel pump flange and remove the pump together with the seals.

Examination

Stir the pump lever. At the same time, suction noise should be clearly audible.

By placing a finger on the holes of the fuel line fittings and at the same time acting on the lever, the pump can be checked for suction and discharge.

At the service station, you can check the discharge pressure at the pump. Prescribed value: between 0.24 and 0.41 bar.

If the prescribed value is not reached, the pump must be replaced. The pump is beyond repair.

Installation

Using a scraper, carefully clean the sealing surfaces of the cylinder block, fuel pump and insulator from seal residues.

Attach the fuel pump with new seals and tighten the mounting bolts to 15 Nm.

Connect the fuel lines according to the markings and secure them with clamps.

Connect ground wire to battery (-).

If available, set the clock and enter the anti-theft code for the radio.

Start the engine and check the tightness of the connection between the fuel lines and the pump.