Chain Brake - Stihl MS 171 Instruction Manual

English

Chain Brake

Locking chain with chain brake
– in an emergency
– when starting
– at idling speed
The chain is stopped and locked when
the hand guard is pushed toward the bar
nose by the left hand – or when brake is
activated by inertia in certain kickback
situations.
30
Releasing the chain brake
N
Pull the hand guard back toward the
front handle.
Always disengage chain brake
before accelerating engine and
before starting cutting work. The
only exception to this rule is when
you check operation of the chain
brake.
High revs with the chain brake
engaged (chain locked) will
quickly damage the powerhead
and chain drive (clutch, chain
brake).
The chain brake is designed to be
activated also by the inertia of the
front hand guard
if the forces are sufficiently high. The
hand guard is accelerated toward the
bar nose - even if your left hand is not
behind the hand guard, e.g. during a
felling cut. The chain brake will operate
only if it has been properly maintained
and the hand guard has not been
modified in any way.
Check operation of chain brake
Before starting work: Run engine at idle
speed, engage the chain brake (push
hand guard toward bar nose).
Accelerate up to full throttle 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, such as your STIHL servicing
dealer, at the following intervals:
Full-time usage:
Part-time usage:
Occasional usage:
MS 171, MS 181, MS 181 C, MS 211, MS 211 C
every 3
months
every 6
months
every 12
months