Pump Diaphragm - Stihl MS 271 Manual

: If there is an annular
indentation (arrow) on the
sealing cone of the inlet needle,
fit a new inlet needle.
Installing
1
: Fit the inlet needle (1).
: Fit the spring (2) in the bore.
1 2 3
: Position the inlet control lever (3)
with spindle (2) on the
spring (arrow) first, then slide the
inlet control lever's clevis into the
groove in the inlet needle (1).
MS 271 C, MS 291 C
Make sure the spring locates on the
control lever's nipple.
– Press the inlet control lever down
and secure it with the screw.
– Check that the inlet control lever
moves freely.
– Install the metering diaphragm,
b 12.6.1

12.6.3 Pump Diaphragm

– Troubleshooting, b 3.6
– Remove the carburetor, b 12.5
1 2
2
: Take out the screw (2).
: Remove the end cover (1).
If the gasket and pump diaphragm
are stuck to the carburetor, remove
them very carefully.
1
2
– Carefully remove the pump
diaphragm with gasket from the
end cover.
: Carefully separate the pump
diaphragm (1) and gasket (2)
– always install a new gasket.
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 pump diaphragm for
signs of damage and wear. Install
a new gasket.
– Check fuel strainer for
contamination and damage.
Clean or replace if necessary.
1
: Use a needle to remove the fuel
strainer (1) from the carburetor
body. Clean or replace the fuel
strainer.
– Reassemble in the reverse
sequence.
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