Stihl MS 661 C-M Installation, Operation & Maintenance Manual

MS 661 C-M
English
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N Remove chain sprocket cover, saw
chain and guide bar.
N Release chain brake – pull hand
guard against the front handle
Fit new chain sprocket
– after use of two saw chains or
earlier
– if the wear marks (arrows) are
deeper than 0.02 in (0.5 mm) –
otherwise the service life of the saw
chain is reduced – use check gauge
(special accessory) to test
Using two saw chains in alternation
helps preserve the chain sprocket.
Use only STIHL original chain sprockets
to help ensure reliable functioning of the
chain brake.
N Use a screwdriver to remove the E-
clip (1)
N Remove the washer (2)
N Remove rim sprocket (3) (if so
equipped), clutch drum (4) and
needle cage (6).
N Inspect transport profile for rim
sprocket on the clutch drum (4) – if
there are also heavy signs of wear,
also replace the clutch drum
N Remove clutch drum with integrated
spur chain sprocket (5) (if so
equipped) including needle cage (6)
from the crankshaft – for
powerheads with Quickstop Plus
chain brake system, depress
throttle trigger lockout beforehand
Install spur chain sprocket / rim sprocket
N Clean crankshaft stub and needle
cage and lubricate with STIHL
lubricant (special accessory)
N Slide needle cage onto the
crankshaft stub
N After refitting, turn the clutch drum
and/or spur chain sprocket approx.
1 full turn so that the carrier for the
oil pump drive engages
N Refit the rim sprocket – cavities
toward the outside
N Refit washer and E-clip on the
crankshaft
Checking and Replacing the
Chain Sprocket
001BA121 KN
001BA122 KN
1
2
4
5
6
1
2
3
6

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