Stihl MS 311 Manual page 76

1
: Carefully separate the pump
diaphragm (2) and gasket (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 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.
MS 311, MS 391
Installing
2
1
2
: Fit the new gasket (1) so that the
contours (arrows) match and it is
held in position by the pegs (2).
2
2
: Fit the pump diaphragm on the
gasket (1) so that the contours
(arrows) match and it is held in
position by the pegs (2).
2
1
: Position the end cover (1) so that
the lever (arrow) points in the
direction of the adjusting screws.
: Fit the end cover (1) from below
so that the pump diaphragm and
gasket are still held in position.
1
2
1
– Move the end cover (1) a little
until its pegs engage the holes in
the carburetor body.
– Check that the pump diaphragm
and gasket are properly seated.
: Fit and tighten down the screw
(2) firmly.
– Reassemble all other parts in the
reverse sequence.
75