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 271, MS 291, MS 291 C
Winter Operation
Pre-heat carburetor
N
Remove the shroud – see "Shroud"
At temperatures below +50 °F
(+10 °C)
every 3
N
Using the combination wrench or a
months
screwdriver, pry the shutter out of
the s (summer operation) position
every 6
months
every 12
months
N
Place the slide with the opening in
the direction of the chain saw
(winter operation) – arrow points
toward symbol r – shutter must
audibly snap into place
In the winter operation position, the tip of
the arrow (1) is visible.
N
Fit the shroud – see "Shroud"
Heated air is now drawn in from around
the cylinder and circulates around the
carburetor – this helps prevent
carburetor icing.
At temperatures above +70 °F
(+20 °C)
N
Ensure that the slide is set back to
position s (summer operation)
without fail, otherwise the engine
may malfunction due to overheating
At temperatures below +14 °F (-10 °C)
In case of erratic idling behavior or poor
acceleration
N
Turn the low speed screw (L)
1/4 turn counterclockwise
Whenever the low speed screw (L) has
been adjusted, it is usually also
necessary to adjust the idle speed
adjusting screw (LA), see "Setting the
carburetor".
N
if the chain saw is extremely cold
(frost formation) – after starting,
bring the engine up to operating
temperature at increased idle speed
(disengage chain brake!)
1
Air filter system
N
Retrofit new air filter if necessary –
see "Air filter system"
English
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