Owner's Manual

MS 251, MS 251 C
English
42
The air filter system can be adapted to
suit different operating conditions by
installing different filters. Changing the
filter is quick and simple.
Fleece filter
N Fleece filter for normal operating
conditions and dry work areas.
HD2 filter
N HD2 filter (black filter frame, pleated
filter material) for extreme wintry
conditions (e.g. powder or drifting
snow) or very dusty work areas.
If there is a noticeable loss of engine
power
N Remove the shroud – see "Shroud"
Removing the air filter
N Clean away loose dirt from around
the filter
NOTICE
Do not use tools to remove and install
the air filter – the air filter could be
damaged in the process.
N Turn air filter 1/4 turn
counterclockwise and remove in the
direction of the rear handle
N Always replace a damaged filter
Cleaning the air filter
N Knock out the filter or blow it clear
with compressed air from the inside
outwards
If knocking-out or blowing-out does not
suffice, or in the case of stubborn dirt or
stuck filter fabric, the filter must be
subjected to a thorough cleaning.
Thorough filter cleaning
N Wash the filter in STIHL special-
purpose cleaner (special
accessory) or a clean, non-
flammable cleaning liquid (e. g.,
warm soapy water) – rinse the filter
from inside to out under a water jet
– do not use high-pressure cleaners
N Dry all filter parts – do not expose to
extreme heat
N Do not oil the filter
N Reinstall filter
Installing the air filter
N Fit air filter
N Press the air filter in the direction of
the filter housing and
simultaneously turn it clockwise
until the air filter engages – the
"STIHL" logo must be horizontal
N Fit the shroud – see "Shroud"
Air Filter System
5902BA009 KN
5902BA008 KN
Cleaning the Air Filter
1.
2710BA000 KN
2.
2710BA001 KN
2.
1.