MS 311, MS 391
English
33
For periods of 3 months or longer
N Drain and clean the fuel tank in a 
well ventilated area.
N Dispose of fuel properly in 
accordance with local 
environmental requirements.
N Run the engine until the carburetor 
is dry – this helps prevent the 
carburetor diaphragms sticking 
together.
N Remove the saw chain and guide 
bar, clean them and spray with 
corrosion inhibiting oil.
N Thoroughly clean the machine – 
pay special attention to the cylinder 
fins and air filter.
N If you use a biological chain and bar 
lubricant, e.g. STIHL BioPlus, 
completely fill the chain oil tank.
N Store the machine in a dry, high or 
locked location, out of the reach of 
children and other unauthorized 
persons.
N Remove chain sprocket cover, saw 
chain and guide bar.
N Release chain brake – pull hand 
guard against the front handle
Fit new chain sprocket
– after use of two saw chains or 
earlier
– if the wear marks (arrows) are 
deeper than 0.5 mm – otherwise the 
service life of the saw chain is 
reduced – use check gauge (special 
accessory) to test
Using two saw chains in alternation 
helps preserve the chain sprocket.
STIHL recommends use of original 
STIHL chain sprockets in order to 
ensure optimal functioning of the chain 
brake.
N Use a screwdriver to remove the E-
clip (1)
N Remove the washer (2)
N Remove rim sprocket (3)
N Inspect transport profile on the 
clutch drum (4) – if there are also 
heavy signs of wear, also replace 
the clutch drum
N Remove clutch drum or spur chain 
sprocket (5) including needle 
cage (6) from the crankshaft – with 
QuickStop Super chain brake, press 
throttle lock beforehand
Storing the Machine Checking and Replacing 
the Chain Sprocket
001BA121 KN
001BA122 KN
1
2
4
5
6
1
2
3
6