Instruction Manual

FS 40, FS 40 C, FS 50, FS 50 C
English
12
of the attachment changes during use,
stop the engine immediately, wait until
the cutting attachment stops, and check
the nut securing the attachment for
tightness and the head for cracks, wear
or other damage.
WARNING
A loose head may vibrate, crack, break
or come off the trimmer, which may
result in serious or fatal injury. Make
sure that the cutting attachment is
properly tightened. Use the wrench
supplied or one of sufficient length to
obtain the proper torque. If the head
loosens after being properly tightened,
stop work immediately. The retaining nut
may be worn or damaged and should be
replaced. If the blade or head continues
to loosen, see your STIHL dealer. Never
use a trimmer with a loose cutting
attachment.
WARNING
Replace a cracked, damaged or worn-
out head or a cracked, bent, warped,
damaged, dull or worn out blade
immediately, even if damage is limited to
superficial cracks. Such attachments
may shatter at high speed and cause
serious or fatal injury.
WARNING
If the head, blade or deflector becomes
clogged or stuck, always shut off the
engine and make sure the cutting
attachment has stopped before
cleaning. Grass, weeds, etc. should be
cleaned off the blade or from around the
head at regular intervals.
WARNING
To reduce the risk of unintentional
rotation of the cutting attachment and
injury, always shut off the engine and
remove the spark plug boot before
replacing the cutting attachment. To
reduce the risk of injury, always shut off
the engine before adjusting the length of
the nylon line on manually adjustable
mowing heads.
WARNING
The gearbox becomes hot during
operation. To reduce the risk of burn
injury, do not touch the gear housing
when it is hot.
WARNING
Never modify your muffler. Any
modification could cause an increase in
heat radiation, sparks or sound level,
thereby increasing the risk of fire, burn
injury or hearing loss. You may also
permanently damage the engine. Have
your muffler serviced and repaired by
your STIHL servicing dealer only.
WARNING
The muffler and other parts of the engine
(e.g. fins of the cylinder, spark plug)
become hot during operation and remain
hot for a while after stopping the engine.
To reduce risk of burns, do not touch the
muffler and other parts while they are
hot. Keep the area around the muffler
clean. Remove excess lubricant and all
debris such as pine needles, branches
or leaves. Let the engine cool down
sitting on concrete, metal, bare ground
or solid wood (away from any
combustible substances, such as dry
brush, grass or wood chips.
WARNING
An improperly mounted or damaged
cylinder housing or a
damaged/deformed muffler shell may
interfere with the cooling process of the
muffler. To reduce the risk of fire or burn
injury, do not continue work with a
damaged or improperly mounted
cylinder housing or a
damaged/deformed muffler shell.
Your muffler is furnished with a spark
arresting screen designed to reduce the
risk of fire from the emission of hot
particles. Never operate your unit with a
missing or damaged spark arresting
screen. If your gas/oil mix ratio is correct
(i.e., not too rich), this screen will
normally stay clean as a result of the
heat from the muffler and need no
service or maintenance. If you
experience loss of performance and you
suspect a clogged screen, have your
muffler maintained by a STIHL servicing
dealer. Some state or federal laws or
regulations may require a properly
maintained spark arrestor for certain
uses. See the "Maintenance, Repair and
Storing" section of these Safety
Precautions. Remember that the risk of
a brush or forest fire is greater in hot or
dry conditions.