Operating Instructions - Stihl MS 171 Instruction Manual

English
► Pull the hand guard toward the handlebar
The chain brake is released – the chain saw is
ready for use.
NOTICE
Open the throttle only when the chain brake is
off. Increased engine speeds with the chain
brake on (saw chain is stationary) will quickly
damage the clutch and chain brake.
18.9 At very low temperatures
► let the engine warm up briefly with the throttle
slightly open
18.10 Switch off the engine
► Move the master control lever to the stop posi‐
tion 0
18.11 If the engine does not start
The master control lever was not returned from
the position choke shutter closed l to starting
acceleration n in time, the engine may be floo‐
ded.
► Move the master control lever to the stop posi‐
tion 0
► Remove the spark plug – see "Spark plug"
► Dry spark plug
► Crank the engine several times with the starter
– to clear the combustion chamber
► Replace the spark plug – see "Spark plug"
30
► Set the master control lever to starting accel‐
eration n – even if the engine is cold
► Restart the engine

19 Operating Instructions

19.1 During the break-in period
A factory new machine should not be run at high
revs (full throttle off load) for the first three tank
fillings. This avoids unnecessarily high loads dur‐
ing the break-in period. As all moving parts have
to bed in during the break-in period, the frictional
resistances in the shortblock are greater during
this period. The engine develops its maximum
power after about 5 to 15 tank fillings.
19.2 During work
NOTICE
Do not make the mixture leaner to achieve an
apparent increase in power – this could damage
the engine – see "Adjusting the Carburetor".
NOTICE
Open the throttle only when the chain brake is
off. Running the engine at high revs with the
chain brake engaged (chain locked) will quickly
damage the shortblock and chain drive (clutch,
chain brake).
19.2.1 Check chain tension frequently
A new saw chain must be retensioned more fre‐
quently than one that has been in use already for
an extended period.
19.2.2 Chain cold
Tension is correct when the chain fits snugly
against the underside of the bar but can still be
pulled along the bar by hand. Retension if neces‐
sary – see "Tensioning the Saw Chain".
19.2.3 Chain at operating temperature
The chain stretches and begins to sag. The drive
links must not come out of the bar groove on the
underside of the bar – the chain may otherwise
jump off the bar. Retension the chain – see "Ten‐
sioning the Saw Chain".
19 Operating Instructions
0458-533-0121-E