Instruction Manual

MS 231, MS 231 C, MS 251, MS 251 C
English
27
Releasing the chain brake
N Pull the hand guard back toward the
front handle,
NOTICE
Always disengage chain brake before
accelerating the engine (except when
checking its operation) and before
starting cutting work.
High revs with the chain brake engaged
(chain locked) will quickly damage the
powerhead and chain drive (clutch,
chain brake).
The chain brake is also activated by the
inertia of the front hand guard if the
kickback force of the saw is high
enough: The hand guard is accelerated
toward the bar nose – even if your left
hand is not behind the hand guard, e.g.
during felling cut.
The chain brake will operate only if the
hand guard has not been modified in any
way.
Check operation of the chain brake
Before starting work: Run engine at idle
speed, engage the chain brake (push
hand guard toward bar nose) and open
the throttle wide for no more than
3 seconds – the chain must not rotate.
The hand guard must be free from dirt
and move freely.
Chain brake maintenance
The chain brake is subject to normal
wear. It is necessary to have it serviced
and maintained regularly by trained
personnel. STIHL recommends that you
have servicing and repair work carried
out exclusively by an authorized STIHL
servicing dealer. Maintain the following
servicing intervals:
Pre-heating carburetor
N Remove the shroud – see "Shroud"
At temperatures below +10 °C
N Using a screwdriver, pry the shutter
out of the s (summer operation)
position
N Place the shutter with the opening in
the direction of the chain saw in
the r position (winter operation) –
shutter must audibly snap into place
N Fit the shroud – see "Shroud"
143BA012 KN
Full-time usage: every 3
months
Part-time usage: every 6
months
Occasional usage: every 12
months
Winter Operation
2310BA000 KN
2310BA001 KN