INSPECTING AND CLEANING THE PUMP
The functioning of the pump can be inspected by letting air bubbles inside the hose.
The fuel progresses 18-20 mm per pump stroke. Slow movement is a sign of a blockage and air bubbles
show that there is an air leak in the suction side or pump. Small sized bubbles do not pose a problem.
Back and forth movement is caused by a leaking non-return valve.
The most common defects of the pump are:
1. Clogging, or the movement of the pump piston is slowed down or hindered altogether due to external
impurities or paraffin.
2. A leaking non-return valve in the suction cycle.
REMOVING SMALL IMPURITIES AND PARAFFIN FROM THE PUMP
1. Remove the pump from the hose connectors.
2. Now you can force isopropanol through the pump with e.g. a syringe.
OPENING AND CLEANING THE PUMP
(only in an extreme emergency; leave this to the service centre, if possible)
1. Remove the pump and remove the hoses from the connectors.
2. Remove the wiring of the pump.
3. Disconnect the wiring connector strip (8) so that it remains attached to the coil wires.
4. Remove the iron shell (1) of the pump by opening its screws.
5. Pull the upper part (3) of the pump out of the coil (4). The piston (9) and spring (10) come loose at the
same time.
6. The lower end of the pump (5) can be removed by pulling as well.
7. Now you can wash the insides of the pump with e.g. isopropanol. There should not be any stiffness
between the piston and the cylinder.
8. Check the functioning of the non-return valve by attaching a piece of hose to pump outlet socket (11)
and blowing air under the liquid surface e.g. with an injection syringe. The valve should not leak. If
necessary, you can try to clean by forcing a powerful flow through the valve downstream.
9.
DO NOT OPEN
the sealed connection (7) between the pump body (6) and the valve body, as it is
adjusted to the correct stroke length.
10. Assemble in the reverse order. Be sure to check the O-rings (12 and 13), as well as the condition and
cleanliness of their grooves.
In order to ensure the tightness of the hoses, check the clamps when installing the pump. Potential leaks
on the suction side or the pump are seen as air bubbles downstream of the pump, even if they cannot be
seen on the suction side. Note that if there is air in the pump, it will take a while for it to be removed.