Winter Operation - Stihl MS 251 C-Q Instruction Manual

Checking operation of the coasting
brake
Before starting work: Open the throttle
wide and then release the rear handle.
The chain must stop moving within less
than a second.
Checking operation of the chain brake
Before starting work: Run engine at idle
speed, engage the chain brake (push
hand guard towards 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.
In case of doubt about the above
functions, contact your servicing dealer
for assistance. STIHL recommends that
you have servicing and repair work
carried out exclusively by an authorized
STIHL servicing dealer.
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:
Full-time usage: every 3
months
Part-time usage: every 6
months
Occasional usage: every 12
months
MS 251 C-Q

Winter Operation

Pre-heating carburetor
Remove the shroud – see "Shroud"
N
At temperatures below +10 °C
Using a screwdriver, pry the shutter
N
out of the s (summer operation)
position
Place the shutter with the opening in
N
the direction of the chain saw in
the r position (winter operation) –
shutter must audibly snap into place
Fit the shroud – see "Shroud"
N
Heated air is now drawn in from around
the cylinder and circulates around the
carburetor – this helps prevent
carburetor icing.
At temperatures above +20 °C
Ensure that the shutter is always
N
returned to position s (summer
operation), otherwise the engine
may malfunction due to overheating
At temperatures below -10 °C
if the chain saw is extremely cold
N
(frost formation) – after starting,
bring the engine up to operating
temperature at increased idle speed
(disengage chain brake!)
In case of erratic idling behavior or poor
acceleration
Turn the low speed screw (L)
N
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".
Air filter system
Retrofit new air filter if necessary –
N
see "Air filter system"
English
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