Stihl MS 661 C-M Instruction Manual

0458-759-8221-C
21
English 6 Kickback and Other Reactive Forces
WARNING
￭ Compliance with the chain saw kickback standards does
not mean that the bar and chain will rotate at most 45° in
a real life kickback.
￭ The computer-derived angles of the chain saw standards
may bear no relationship to actual kickback bar rotation
angles that may occur in a real life cutting situation.
￭ Devices designed to reduce the risk of kickback injuries
may lose some of their effectiveness when they are no
longer in their original condition, especially if they have
been improperly maintained.
– Read and follow the safety precautions and
instructions in this manual.
– When working, always position the chain saw such
that your body is clear of the cutting attachment and
outside of the cutting plane.
– Follow the maintenance and service instructions in
this manual.
￭ For the chain saw to meet the chain saw kickback
standards, use only the following cutting attachments:
– Compliant bar and chain combinations listed in
"Combinations of Guide Bars and Saw Chains,"
@ 26.1;
– Other replacement bar and chain combinations
marked in accordance with the standards for use on
the chain saw; or
– Replacement chain designated "low kickback chain."
6.2.3 Devices for Reducing the Risk of Kickback Injury
The STIHL Quickstop chain brake and STIHL's green-
labeled, reduced kickback bars and green-labeled, low
kickback chains are designed to reduce the risk of kickback
injury.
1. STIHL Quickstop Chain Brake
There are two mechanisms for activating the chain brake if
it is in a properly maintained condition:
– Manual Activation: If a kickback occurs, the chain saw
moves upwards toward the user in a rotating motion
around the front handle. The brake is designed to engage
if the left hand contacts the front hand guard, which is the
activation lever for the brake, and pushes it forward.
– Inertia Activation: All STIHL chain saws are equipped with
an inertia Quickstop chain brake. If the kickback impulse
is strong enough, this alone is sufficient to engage the
brake even without contacting the front hand guard.
WARNING
￭ To reduce the risk of kickback injury:
– Never use a saw if the chain brake does not function
properly.
– When in doubt, take the saw to an authorized STIHL
servicing dealer for inspection and/or repair.
– Do not use the saw until the problem has been
corrected.
￭ In a kickback situation, the front hand guard helps protect
your left hand from contacting the chain. Removal of the
front hand guard on a chain saw equipped with a
0000-GXX-4568-A0

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