Husqvarna K 960 Workshop Manual page 26

CARBURETTOR
A
A
Measurement chamber – function
The measurement chamber has two chambers: The air chamber (towards the
cover) and the fuel chamber (towards the carburettor body). These are separated
by the measuring chamber diaphragm. The diaphragm controls and maintains
a constant fuel level in the fuel chamber through the mechanically connected
needle valve.
The air chamber is connected with the inlet, after the air filter, and gives the
air chamber the same pressure (SmartCarb™ filter compensation).
Measurement chamber diaphragm – inspection
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.
Needle valve
Perform a pressure test as pre-
viously described. If the test
indicates a leaking needle valve,
it must be dismantled.
Check that the spring is not
deformed 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 or
the tip of the needle is deformed
it must be replaced. (The picture
shows a new needle tip.)
Clean the seating
Measurement chamber
Note the interrelated positions of the
components when dismantling, as they
can be reassembled in the wrong order.
The gaskets A are identical.
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.
Check that the spring is not deformed
and that the lever runs easily on the axle.
When reassembling: Note that the lever
has two forks where the needle valve and
measurement chamber diaphragm fit.
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.)
Clean the seating
Check whether there is dirt on the needle
valve's seating. If compressed air is used
for cleaning, the pump diaphragm must
be dismantled to prevent damage from
over pressure.
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