Husqvarna K 1260 Workshop Manual page 27

11
A
27
CARBURETTOR
Pump unit
Function
The pump diaphragm (A) is driven by the pressure variations in the crankcase,
which are led to the top of the pump diaphragm.
The fuel on the underside of the diaphragm is pumped to the valves (B).
The counter pressure of the measurement chamber diaphragm against the
B
needle valve in the measurement chamber controls the valves' degree of
opening and the quantity of fuel pumped into the measurement chamber's
fuel side.
Inspection
Pump diaphragm leakage is
checked as previously described.
Check that the valve flaps
closed tightly against the carbu-
rettor housing.
Fuel strainer
Inspect the strainer with a
magni fying glass. Loose dirt
particles can be blown away
from the needle valve's seating.
Replace the strainer if it is
defective. Dismantle with a
needle and assemble with a 7
mm pin punch.
Inspection
Pump diaphragm leakage is checked as
previously described.
The function of the valve flaps cannot
be pressure tested and must be visually
inspected. The valve flaps must be abso -
lutely flat and close tight against the car-
burettor housing in order for the pump
function to work. If the flaps show signs
of buckling, fatigue or cracking, the dia -
phragm must be replaced.
Fuel strainer
There is a fine-meshed strainer located on
the fuel inlet to the carburet tor. Inspect
this with a magnifying glass. Loose dirt
particles can be blown away from the
needle valve's seating. If there are depo-
sits that are hard to remove or the mesh
is damaged the strainer must be replaced.
The strainer is dismantled using a
needle or awl. Fit the new strainer with a
.3 in./7 mm pin punch.
Channels
Blowing clean the carburettor
In connection with a service on the
carburettor it is appropriate to blow out
any particles from the channels using
compressed air. The measurement cham-
ber diaphragm and the pump diaphragm
as well as the needle valve must be dis-
mantled before starting to blow clean.
Open the choke valve to give free air
passage through the venturi.
The rings indicate where blowing clean
should be done.