Servicing The Carburetor; 14.4.1 Metering Diaphragm - Stihl MS 200 Service Manual

2
1
– 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).
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 14.4.2
2. Metering diaphragm or gasket
damaged, replace if necessary,
b 14.4.1
3. Pump diaphragm or
gasket damaged, replaced
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,
MS 200 b 14.2,
MS 200 T b 14.2.1
– Tightening torques, b 3.5
– Reassemble all other parts in the
reverse sequence.
MS 200, MS 200 T
14.4

Servicing the Carburetor

14.4.1 Metering Diaphragm

1
– Troubleshooting, b 4.6
– Remove the carburetor,
MS 200 b 14.2,
MS 200 T b 14.2.1
: Take out the screws (arrows).
– Remove the end cover (1).
If the gasket and diaphragm are
stuck to the carburetor, remove
them very carefully.
1
: Carefully separate the metering
diaphragm (1) and gasket (2).
The diaphragm material is
subjected to continuous alternating
stresses and eventually shows
signs of fatigue, i.e. the diaphragm
distorts and swells and has to be
replaced.
– Check the metering diaphragm
for signs of damage and wear.
Install a new gasket.
2
1
3
– Note correct positions of
metering diaphragm (1) and
gasket (2), and place them on the
end cover (3).
: Fit the metering diaphragm (1) on
the peg (arrow) first, then the
gasket (2).
1
2
– Position the end cover (1) so that
the stub (2) points towards the
adjusting screws.
: Hold the end cover (1) so that the
metering diaphragm and gasket
remain in position. Carefully fit
the end cover
– the peg on the end cover must
engage the bore (arrow) in the
carburetor.
2
95