Stihl MS 661 C-M User Manual

104 MS 661, MS 661 C-M
13.5.5 Pump Diaphragm
– Troubleshooting, b 3.6
– Remove the carburetor, b 13.4
Versions without carburetor
heating
: 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.
1166RA251 TG
1
2 1
1
1
Versions with carburetor heating
: Take out the screws (1) and
remove the thermostatic
switch (2) and end cover (3).
All models
If the gasket and pump diaphragm
are stuck to the carburetor, remove
them very carefully.
: 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.
1166RA252 TG
1
2 1
1
1
3
1166RA253 TG
2
1
– Check fuel strainer for
contamination and damage.
Clean or replace if necessary.
: 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
: Fit the new gasket (1) so that it
contours match the end cover (2)
and its holes engage the
pegs (3).
1166RA254 TG
1
1166RA255 TG
1
3
3
2

Stihl MS 661 C-M Specifications

General

Idle speed	- RPM
Motor type	2-stroke motor
Chain pitch	3/8 \
Blade length	800 mm
Product color	Black, Grey, Orange
Automatic oiling	Yes
Engine displacement	91.1 cm³
Power source	Gasoline
Sound power level	118 dB
Vibration emission	6.9 m/s²
Sound pressure level	105 dB

Weight and Dimensions

Weight	7400 g