Operation Manual
87MS 240, MS 260, MS 260 C
: Push the fuel hose with nipple 
onto the carburetor’s fuel stub 
(arrow).
– Push the pressure hose of pump 
0000 850 1300 on to the nipple.
: Push the ring (1) to the right and 
pump air into the carburetor until 
the pressure gauge (2) indicates 
a pressure of about 0.8 bar 
(80 kPa).
165RA337 TG
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165RA338 TG
If this pressure remains constant, 
the carburetor is airtight. However, if 
it drops, there are three possible 
causes:
1. The inlet needle is not sealing
(foreign matter in valve seat, 
sealing cone of inlet needle
is damaged or 
inlet control lever is sticking). 
Remove to clean, 
b 14.4.1
2.  Metering diaphragm or gasket 
damaged, replace if necessary, 
b 14.4
3. Pump diaphragm or 
gasket damaged, replace 
if necessary, b 14.4.3
– After completing the test, push 
the ring (1) to the left to vent the 
system and then pull the fuel 
hose off the carburetor.
– Install the carburetor, b 14.2
– Tightening torques, b 3.5
– Reassemble all other parts in the 
reverse sequence.
14.4 Servicing the Carburetor
– Troubleshooting, b 4.6
– Remove the carburetor, b 14.2
– Disconnect the throttle rod, 
b 14.6
: Take out the screws (arrows).
Versions with handle and 
carburetor heating
: Remove the retainer (1) and 
thermostatic switch (2).
165RA339 TG
165RA340 TG
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