Stihl MS 661 C-M User Manual

111MS 661, MS 661 C-M
Saw chain runs while engine is
idling
– Turn the idle speed screw (LA)
counterclockwise until the chain
stops running, then turn it back
11/2turns.
Erratic idling behavior, poor
acceleration
(although low speed screw = 1/4)
Idle setting too lean.
– Warm up the engine.
– Turn the low speed screw (L)
counterclockwise until the engine
runs and accelerates smoothly.
It is usually necessary to change the
setting of the idle speed screw (L)
after every correction to the low
speed screw (LA).
Fine tuning for operation at high
altitude
A minor correction may be
necessary if engine power is not
satisfactory when operating at high
altitude.
– Check "Setting".
– Warm up the engine.
– Turn the high speed screw (H)
slightly clockwise (leaner) – no
further than stop on versions with
limiter caps.
Turn the adjusting screws only very
slightly. Even minor adjustments
can noticeably affect engine running
behavior.
If the setting is made too lean there
is a risk of engine damage as a
result of lack of lubrication and
overheating.
Readjust carburetor to "Standard
Setting" after returning from high
altitude.
13.9 Manifold
A damaged intake manifold can
cause engine running problems,
b 3.7
– Troubleshooting, b 3.6 or
b 3.7
– Remove the shroud, b 6.4
– Remove the stop buffer at the
clutch side, b 10.1
– Remove the carburetor, b 13.4
: Remove the washer (1) and
sleeve (2).
1166RA041 TG
2
1
: Take out the screw (1), push the
tank housing (2) down a little and
hold it there.
: Push the manifold flange (1) out
of the tank housing in the
direction of the cylinder.
– Pull the tank housing out part way
– do not overtension wiring
harness and do not pull the
impulse hose off the stub.
: Loosen the screw (1) and slip the
hose clamp over the manifold (2)
in the direction of the tank
housing.
1166RA183 TG
1
2
1166RA348 TG
1
12
1166RA349 TG

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