Stihl 064 Service Manual page 78

STIHL 064, 066
11.3 Leakage Testing the
Carburetor
Top:
Fuel line fitted on elbow connector
Bottom:
Fuel line 1110 141 8600 fitted
on nipple 0000 855 9200
Troubleshooting chart - see 2.4.
The carburetor can be tested for
leaks with the carburetor and
crankcase tester.
- Remove the air filter - see 11.1.
- Pull fuel hose off carburetor's
elbow connector.
Top:
Tester's fuel line fitted on
elbow connector
Bottom:
Nipple connected to pressure hose
- Push fuel line with nipple onto
the elbow connector. Connect
nipple to tester's pressure hose.
- Close the vent screw on the
rubber bulb and pump air into
the carburetor until the pres-
sure gauge shows a reading of
approx. 0.4 bar (5.7 psi).
Top:
Pressure testing carburetor
with carburetor crankcase tester
1106 850 2905
Bottom:
Damaged inlet needle
If this pressure remains constant,
the carburetor is airtight. However,
if it drops, there are two possible
causes:
1. The inlet needle is not sealing
(foreign matter in valve seat or
sealing cone of inlet needle is
damaged or inlet control lever
sticking).
2. The metering diaphragm is
damaged.
In either of these cases the car-
buretor must be removed and
serviced - see 11.5.
78