Servicing The Carburetor; Metering Diaphragm; Inlet Needle - Stihl MS 231 Manual

12.6

Servicing the Carburetor

12.6.1 Metering Diaphragm

– Troubleshooting, b 3.6
– Remove the carburetor, b 12.5
: 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
: Check the O-ring (1) and replace
it if necessary
: On versions with a manual fuel
pump, check the nipple (2) and
replace the end cover if
necessary.
90
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2 1
: Carefully separate the metering
diaphragm (1) and gasket (2).
1
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.
Installing
1
2
2
– Note installed positions of
metering diaphragm (2) and
gasket (1).
: Position the gasket (1) and
metering diaphragm (2) so that
pegs (arrows) engage the small
holes in the tabs.
2 1
3
: Position the end cover (1) so that
the stub (3) points in the direction
of the choke shutter and the
holes line up.
: Fit the screws (2) but do not
tighten them down yet.
– Check position of metering
diaphragm and gasket, then
tighten down the screws firmly in
a crosswise pattern.
Take care not to damage the O-
ring (arrow).
– Reassemble all other parts in the
reverse sequence.

12.6.2 Inlet Needle

– Remove the metering
diaphragm,
b 12.6.1
MS 231, MS 231 C, MS 251, MS 251 C
2
2
2