Stihl MS 661 C-M User Manual

24 MS 661, MS 661 C-M
6. Engine
6.1 Muffler
Always check and, if necessary,
repair the fuel system, carburetor,
air filter and ignition system before
looking for faults on the engine.
– Check M-Tronic models with
STIHL MDG 1 using
troubleshooting chart, b 8.7
– Troubleshooting, b 3
To ensure that no dirt particles enter
the cylinder, set the piston to top
dead center before removing the
muffler – top dead center is reached
when the magnet poles ("N / S") on
the flywheel face upwards.
: Take out the screws (1, 2).
: Remove the top casing (3),
check it and replace if necessary.
: Remove the gasket (1) and take
out the screws (2)
– always install a new gasket.
1166RA032 TG
2
2
3
1
1
1166RA033 TG
1
2 2
– Remove and inspect the muffler
and replace it if necessary.
: Remove oil muffler gasket (1)
and heat shield (2) – always
install a new gasket.
– Remove and install the spark
arresting screen – see instruction
manual.
Installing
– Clean away any dirt from the
cylinder and exhaust port.
: Check and clean the sealing
faces (arrows) on exhaust port,
heat shield and muffler, remove
any gasket residue – make sure
there is no gasket residue or dirt
particles in the exhaust port.
Always replace components with
damaged sealing faces.
1166RA034 TG
1
2
1166RA035 TG
: Insert screws (1) through the
muffler and fit the muffler
gasket (2).
: Hold the heat shield (3) with the
pegs facing the muffler so that
the contour (arrow) is next to the
muffler outlet and then push it
into position.
: Coat screw holes (arrows) and
screws (2) with threadlocking
adhesive
– only coat threads in screw
holes (arrows), not the pilot
holes, b 16
: Carefully place muffler (1) with
gasket and heat shield in position
and insert the screws (2).
– Check position of muffler gasket
and heat shield.
: Insert and tighten down the
screws (2) firmly.
1166RA036 TG
13
2 1
2
2
1166RA037 TG
1

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