Leakage Test (Pressure Test) On Carburetor - Stihl 009 User Manual

STIHL 009, 010, 011
8.3 Leakage Test (Pressure Test)
on Carburetor
Tester connected
The carburetor can be tested for
leaks with the carburetor and
crankcase tester 1106 850 2900.
First remove the filter cover and filter
plate and disconnect the fuel line
from the elbow connector. As the
inside diameter of the test hose is
larger than the outside diameter of
the elbow connector, a fuel line
(1120 358 0700) must be used as
an adapter to make the connection.
Push one end of the fuel line onto the
elbow connector and the other end
into the test hose.
Now close the vent screw on the
rubber bulb and pump air into the
carburetor until the pressure gauge
indicates a pressure of 0.4 to 0.5 bar.
If this pressure remains constant, the
carburetor is airtight. However, if it
drops, there are two possible causes:
Bottom:
Correct position of fuel line
1. The inlet needle is not sealing
(foreign matter in valve seat or
cone of inlet needle is damaged).
2. The metering diaphragm is dama-
ged.
In either of these cases the carbure-
tor must be removed and repaired. It
is necessary to unscrew the carbure-
tor mounting screws and raise the
carburetor in order to refit the fuel
line.
Removing the carburetor
First remove the filter cover and filter
plate and pull the fuel line off the car-
buretor. Take out the two pan head
screws. Lift out the carburetor and
disconnect the throttle cable from the
lever on the throttle shaft - this is best
done with the throttle shaft in the full-
throttle position; the same applies for
reassembly.
There is a gasket at both sides of the
diaphragm, between the carburetor
and crankcase flange. Replace these
gaskets when installing the carbu-
retor. Coat the sealing faces with a
little jointing paste, taking care not to
cover the pulse bore.
It is still necessary to unscrew and lift
the carburetor even if only the throttle
cable is faulty.
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