Carburetor; Assembling The Carburetor; 13.5.3 Metering Diaphragm - Stihl MS 661 Manual

– Clean all disassembled parts with
a brush and a standard solvent-
based degreasant containing no
chlorinated or halogenated
hydrocarbons.
– Blow out loose dirt in metering
and pump chambers with
compressed air or remove with a
brush.
13.5.2 Assembling the

Carburetor

Perform the following steps on a
clean base (cloth, paper):
– Inspect fuel strainer. If there are
hard deposits or the surface is
damaged or misshapen, install a
new strainer.
– Check shape and tip of inlet
needle – replace needle if
damaged or worn, b 13.5.4
– Install new diaphragm and
gaskets.
– After installing and adjusting the
carburetor, use new limiter caps.

13.5.3 Metering Diaphragm

– Troubleshooting, b 3.6
– Remove the carburetor, b 13.4
– Check the sleeve, remove and
replace it if necessary.
102
All models
2 1
1
1
: Take out the screws (1) and
remove the end cover (2).
If the gasket and metering
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.
Installing
2
1
1
3
Note installed positions of
gasket (1) and metering
diaphragm (2).
: Position the gasket (1) and
metering diaphragm (2) so that
the pegs (3) engage the holes.
2
2
: Position the end cover (1) so that
the stub (arrow) points in the
direction of the choke shutter.
: Line up the end cover (1) so that
the holes engage the pegs (2).
3
1
2
MS 661, MS 661 C-M