Owner's Manual

MS 251, MS 251 C
English
55
Cooling inlets Clean X
Air inlet on fan housing Clean X XX
Cylinder fins Clean XX X
Preseparator port and carburetor body Clean X
"Carb preheat" shutter and preheating port Clean (winter operation only) X
Carburetor
Check idle adjustment – chain must not
rotate
XX
Readjust idle X
Spark plug
Readjust electrode gap X
Replace after every 100 operating hours
All accessible screws and nuts (not adjust-
ing screws)
3)
Retighten X
Spark arresting screen
4)
in muffler
Check X
Clean or replace X
Chain catcher
Check X
Replace X
Exhaust port
Decoke after first 139 hours of opera-
tion, then every 150 hours
X
Safety labels Replace X
1)
STIHL recommends a STIHL servicing dealer.
2)
see chapter on "Chain Brake"
3)
Firmly tighten down the cylinder base screws of professional saws (3.4 kW or more) after 10 to 20 hours of operation.
4)
not in all versions, market-specific
The following intervals apply to normal operating conditions only. If your daily work-
ing time is longer or operating conditions are difficult (very dusty work area, resin-
rich wood, tropical wood, etc.), shorten the specified intervals accordingly. If you only
use the saw occasionally, extend the intervals accordingly.
before starting work after finishing work or daily after each refueling stop weekly monthly every 12 months if problem if damaged if required