CARBURETTOR
10
25
Metering unit
Fuel chamber
Note the interrelated positions of the
components when dismantling, as they
can be reassembled in the wrong order.
The gaskets A are identical.
A
A
Needle valve
A faulty needle valve is the most com-
mon cause of malfunction caused by the
carburettor. Perform a pressure test as
previously described. If the test indicates
a leaking needle valve, proceed as follows:
Dismantle the screw holding the axle and
remove the components.
Needle valve
Perform a pressure test as
previously described. If the test
indicates a leaking needle valve,
proceed as follows: Dismantle
the screw holding the axle and
remove the components.
Measurement chamber diaphragm
The air volume above the diaphragm acts
as an air spring and is a pre requisite for
the fuel to be pumped to the fuel cham-
ber on the underside.
Make a visual inspection of the dia -
phragm with regard to cracks and leakage.
Fuel on the top, towards the cover, indi-
cate leakage. Change the diaphragm.
Measurement chamber
diaphragm
Make a visual inspection of the
diaphragm with regard to cracks
and leakage.
Fuel on the top, towards the
cover, indicate leakage. Change
the diaphragm.
Check that the spring is intact and that
the lever runs easily on the axle.
Check that the spring is intact
and that the lever runs easily on
the axle.
Inspect the tip of the needle with
a magnifying glass
If there are signs of deposits that cannot
be removed easily or the tip of the needle
is deformed (waistline) after the seating
that it seals against, the needle valve
should be replaced. Always replace in
uncertain cases.
See the needle valve as a wear part that
needs to be replaced during the life of the
machine. (The picture shows a new needle
tip.)
Inspect the tip of the
needle with a magnifying
glass
If there are signs of deposits or
the tip of the needle is deformed
(waistline) after the seating that
it seals against, the needle valve
should be replaced. Always
replace in uncertain cases. (The
picture shows a new needle tip.)
Clean the seating
Check whether there is dirt on the needle
valve's seating. Blown clean with com-
pressed air.
Clean the seating
Check whether there is dirt on
the needle valve's seating. Blown
clean with compressed air.