MS 311, MS 391
English
15
N Fit the guide bar over the studs (1) – 
the cutting edges on the top of the 
bar must point to the right.
N Engage the peg of the tensioner 
slide in the locating hole (2) –- place 
the chain over sprocket (3) at the 
same time.
N Turn the tensioning 
screw (4)clockwise until there is 
very little chain sag on the 
underside of the bar – and the drive 
link tangs are engaged in the bar 
groove.
N Refit the sprocket cover and screw 
on the nuts only fingertight.
N Go to chapter on "Tensioning the 
Saw Chain"
Retensioning during cutting work:
N Shut off the engine.
N Loosen the nuts.
N Hold the bar nose up.
N Use a screwdriver to turn the 
tensioning screw (1) clockwise until 
the chain fits snugly against the 
underside of the bar.
N While still holding the bar nose up, 
tighten down the nuts firmly.
N Go to "Checking Chain Tension".
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
N Check chain tension frequently – 
see chapter on "Operating 
Instructions".
N Shut off the engine.
N Wear work gloves to protect your 
hands.
N The chain must fit snugly against 
the underside of the bar and it must 
still be possible to pull the chain 
along the bar by hand.
N If necessary, retension the chain.
A new chain has to be retensioned more 
often than one that has been in use for 
some time.
N Check chain tension frequently – 
see chapter on "Operating 
Instructions".
3
1
1
2
4
001BA187 KN
Tensioning the Chain
1
133BA024 KN
Checking Chain Tension
143BA007 KN