13.5.5 Pump Diaphragm - Stihl MS 661 Manual

13.5.5 Pump Diaphragm

– Troubleshooting, b 3.6
– Remove the carburetor, b 13.4
Versions without carburetor
heating
2 1
1
1
: Take out the screws (1).
: Remove the end cover (2).
If the gasket and pump diaphragm
are stuck to the carburetor, remove
them very carefully.
104
Versions with carburetor heating
2 1
1
1
: Take out the screws (1) and
remove the thermostatic
1
switch (2) and end cover (3).
All models
If the gasket and pump diaphragm
are stuck to the carburetor, remove
them very carefully.
2
: Carefully separate the pump
diaphragm (1) and gasket (2)
– Inspect the end cover and
replace if necessary.
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.
3
1
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.
Installing
1
1
3
2
: Fit the new gasket (1) so that it
contours match the end cover (2)
and its holes engage the
pegs (3).
MS 661, MS 661 C-M
3