Stihl FS 55 Instruction Manual
STIHL FS 55
STIH)
Instruction Manual
Manual de instrucciones
Warning!
Read and follow all safety precautions in
Instruction Manual – improper use can cause
serious or fatal injury.
Advertencia!
Lea y siga todas las precauciones de
seguridad dadas en el manual de
instrucciones – el uso incorrecto puede
causar lesiones graves o mortales.
Contents
English / USA
Guide to Using this Manual .............. 2
Safety Precautions and Working
Techniques ....................................... 3
Approved Combinations of
Mowing Tool, Deflector,
Handle and Harness ....................... 18
Mounting the Bike Handle .............. 20
BA_SE_012_006_01_13.fmPrinted on chlorine-free paper.
Mounting the Loop Handle ............. 21
Fitting the Carrying Eye .................. 22
Mounting the Deflector ................... 23
Mounting the Cutting Tools ............. 23
Fuel ................................................ 28
Fueling ............................................ 29
Fitting the Harness ......................... 29
Balancing the Brushcutter .............. 30
Starting / Stopping .......................... 31
Operating Instructions .................... 35
Cleaning the Air Filter ..................... 35
Motor Management ........................ 36
Adjusting the Carburetor ................ 36
Printing inks contain vegetable oils; paper can be recycled.
Checking the Spark Plug ................ 38
Rewind Starter ................................ 39
Storing the Machine ....................... 39
Lubricating the Gearbox ................. 39
Sharpening Metal Cutting Tools ..... 40
Inspections and Maintenance
by STIHL Service ........................... 41
Maintenance Chart ......................... 42
Parts and Controls ......................... 43
Specifications ................................. 45
Special Accessories ....................... 46
Maintenance and Repairs .............. 47
STIHL Incorporated
Federal Emission Control
Warranty Statement ........................ 48
STIHL Incorporated California
Exhaust and Evaporative Emissions
Control Warranty Statement ........... 50
Trademarks .................................... 52
Allow only persons who understand this
manual to operate your trimmer/
brushcutter.
To receive maximum performance and
satisfaction from your STIHL trimmer/
brushcutter, it is important that you read
and understand the maintenance and
safety precautions, starting on page 3,
before using your trimmer/brushcutter.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
!Warning!
Because a trimmer/brushcutter is a highspeed cutting tool some special safety
precautions must be observed to reduce
the risk of personal injury.
Careless or improper use may cause
serious or even fatal injury. Make sure
your unit is equipped with the proper
deflector, handle and harness for the
type of cutting attachment being used.
Always wear proper eye protection.
STIHL's philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements are made from time to time. If the
operating characteristics or the appearance of your trimmer/brushcutter differs
from those described in this manual,
please contact your STIHL dealer for
information and assistance.
STIHl
© ANDREAS STIHL AG & Co. KG, 2007
0458 233 8621 C. M15. K7. CP. Printed in USA
1FS 55
English / USA
Guide to Using this Manual
Pictograms
All the pictograms attached to the
machine are shown and explained in
this manual.
The operating and handling instructions
are supported by illustrations.
Symbols in text
The individual steps or procedures
described in the manual may be marked
in different ways:
: A bullet marks a step or procedure
without direct reference to an
illustration.
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration.
Example:
Loosen the screw (1)
Lever (2) ...
In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are marked with the
symbols described below:
Warning where there is a risk of an
accident or personal injury or
serious damage to property.
Caution where there is a risk of
damaging the machine or its
individual components.
Note or hint which is not essential
for using the machine, but may
improve the operator’s understanding of the situation and result
in better use of the machine.
Note or hint on correct procedure in
order to avoid damage to the
environment.
Equipment and features
This instruction manual may refer to
several models with different
features. Components that are not
installed on all models and related
applications are marked with an
asterisk (*). Such components may
be available as special accessories
from your STIHL dealer.
Engineering improvements
STIHL’s philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time to time. If the
operating characteristics or the
appearance of your machine differ from
those described in this manual, please
contact your STIHL dealer for
assistance.
Therefore some changes, modifications
and improvements may not be covered
in this manual.
2
FS 55
Safety Precautions and
Working Techniques
English / USA
Because a trimmer/
brushcutter is a highspeed, fast-cutting power
tool sometimes equipped
with sharp cutting blades,
special safety precautions
must be observed to reduce the risk of
personal injury.
It is important that you
read, fully understand and
observe the following
safety precautions and
warnings. Read the
instruction manual and
the safety precautions periodically.
Careless or improper use may cause
serious or fatal injury.
The terminology utilized in this manual
when referring to the power tool reflects
the fact that different types of cutting
attachments may be mounted on it. The
term "trimmer" is used to designate an
FS unit that is equipped with a nylon line
head or a head with flexible plastic
blades (i.e., the PolyCut head). A
"brushcutter" designates a unit
equipped with a rigid metal blade. Many
FS models may be used as either a
trimmer or a brushcutter - therefore, the
power tool is referred in this manual as a
"trimmer/brushcutter." Some smaller
and/or lightweight FS models may only
be used as a trimmer, i.e., they may not
be used with metal blades.
!Warning
As more fully explained later in these
Safety Precautions, to reduce the risk of
personal injury, make sure your unit is
equipped with the proper handle,
harness and deflector for the type of
cutting attachment you are using. Use
only cutting attachments that are
specifically authorized by STIHL for use
on your FS model.
Have your STIHL dealer show you how
to operate your power tool. Observe all
applicable local safety regulations,
standards and ordinances.
!Warning!
Do not lend or rent your power tool
without the instruction manual. Be sure
that anyone using it understands the
information contained in this manual.
!Warning!
The use of this machine may be
hazardous. If the rotating line or blade
comes in contact with your body, it will
cut you. When it comes in contact with
solid foreign objects such as rocks or
bits of metal, it may fling them directly or
by ricochet in the direction of bystanders
or the operator. Striking such objects
could damage the cutting attachment
and may cause blades to crack, chip or
break. Thrown objects, including broken
heads or blades, may result in serious or
fatal injury to the operator or bystanders.
STIHL does not recommend the use of
rigid blades when cutting in stony areas.
Use your trimmer/brushcutter equipped
with the appropriate cutting attachment
only for cutting grass and similar
material. It must not be used for any
other purposes, since such misuse may
result in an accident or damage to the
machine.
!Warning!
Minors should never be allowed to use
this power tool. Bystanders, especially
children, and animals should not be
allowed in the area where it is in use.
3FS 55
English / USA
!Warning!
To reduce the risk of injury to bystanders
and damage to property, never let your
power tool run unattended. When it is
not in use (e.g. during a work break),
shut it off and make sure that
unauthorized persons do not use it.
Most of these safety precautions and
warnings apply to the use of all STIHL
trimmer/brushcutters. Different models
may have different parts and controls.
See the appropriate section of your
instruction manual for a description of
the controls and the function of the parts
of your model.
Safe use of a trimmer/brushcutter
involves
1. the operator
2. the power tool
3. the use of the power tool.
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.
!Warning!
Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition that
might be aggravated by strenuous work,
check with your doctor before operating
this machine.
!Warning!
Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger
disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
These conditions reduce the hand's
ability to feel and regulate temperature,
produce numbness and burning
sensations and may cause nerve and
circulation damage and tissue necrosis.
All factors which contribute to whitefinger disease are not known, but cold
weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
disease. In order to reduce the risk of
whitefinger disease and carpal tunnel
syndrome, please note the following:
Most STIHL power tools are available
with an anti-vibration (“AV”) system
designed to reduce the transmission of
vibrations created by the machine to the
operator's hands. An AV system is
recommended for those persons using
power tools on a regular or sustained
basis.
4
FS 55
English / USA
Keep the AV system well maintained. A
power tool with loose components or
with damaged or worn AV buffers will
tend to have higher vibration levels.
Maintain a firm grip at all times, but do
not squeeze the handles with constant,
excessive pressure. Wear gloves and
keep your hands warm. Take frequent
breaks.
All the above-mentioned precautions do
not guarantee that you will not sustain
whitefinger disease or carpal tunnel
syndrome. Therefore, continual and
regular users should closely monitor the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
!Warning!
The ignition system of the STIHL unit
produces an electromagnetic field of a
very low intensity. This field may
interfere with some pacemakers. To
reduce the risk of serious or fatal injury,
persons with a pacemaker should
consult their physician and the
pacemaker manufacturer before
operating this tool.
Proper Clothing
To reduce the risk of injury, the operator
should wear proper protective apparel.
!Warning!
The deflector provided with your power
tool will not protect the operator from all
foreign objects (gravel, glass, wire, etc.)
thrown back by the rotating cutting
attachment. Thrown objects may also
ricochet and strike the operator.
!Warning!
To reduce the risk of injury
to your eyes never
operate your power tool
unless wearing goggles or
properly fitted protective
glasses with adequate top
and side protection complying with ANSI
Z 87.1 (or your applicable national
standard). To reduce the risk of injury to
your face STIHL recommends that you
also wear a face shield or face screen
over your goggles or protective glasses.
!Warning!
Power tool noise may
damage your hearing.
Wear sound barriers (ear
plugs or ear mufflers) to
protect your hearing.
Continual and regular
users should have their hearing checked
regularly.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
Always wear gloves when
handling the machine and
metal blades. Heavy-duty,
nonslip gloves improve
your grip and help to
protect your hands.
Clothing must be sturdy
and snug-fitting, but allow
complete freedom of
movement. Wear long
pants made of heavy
material to help protect
your legs. Do not wear
shorts, sandals or go
barefoot.
5FS 55
English / USA
Avoid loose- fitting jackets,
scarfs, neckties, jewelry,
flared or cuffed pants,
unconfined long hair or
anything that could
become caught on
branches, brush or the moving parts of
the unit. Secure hair so it is above
shoulder level.
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended.
Wear an approved safety
hard hat to reduce the risk
of injury to your head
when there is a danger of
head injuries.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
“Main Parts and Controls.”
!Warning!
Never modify this power tool in any way.
Only attachments supplied by STIHL
and expressly approved by STIHL for
use with the specific STIHL model are
authorized. Although certain
unauthorized attachments are useable
with STIHL power tools, their use may, in
fact, be extremely dangerous. For the
cutting attachments authorized by
STIHL for your unit, see the chapter
“Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness“ in the instruction manual or the
STIHL “Power Tools and Accessories“
catalog.
If this tool is subjected to unusually high
loads for which it was not designed (e.g.
heavy impact or a fall), always check
that it is in good condition before
continuing work. Check in particular that
the fuel system is tight (no leaks) and
that the controls and safety devices are
working properly. Do not continue
operating this machine if it is damaged.
In case of doubt, have it checked by your
STIHL servicing dealer.
THE USE OF THE POWER TOOL
Transporting the Power Tool
!Warning!
To reduce the risk of injury from loss of
control and blade or line contact, never
carry or transport your power tool with
the cutting attachment moving.
389BA019 KN
It may be carried only in a horizontal
position. Grip the shaft in a manner that
the machine is balanced horizontally.
Keep the hot muffler away from your
body and the cutting attachment behind
you.
6
FS 55
English / USA
!Warning!
Always shut off the engine and make
sure the cutting attachment has stopped
before putting a trimmer/brushcutter
down. When transporting it in a vehicle,
properly secure it to prevent turnover,
fuel spillage and damage to the unit.
STIHL recommends that you keep metal
blades covered with the transport guard
(optional accessory).
Fuel
Your STIHL power tool uses an oilgasoline mixture for fuel (see the chapter on “Fuel” of your instruction manual).
!Warning!
Gasoline is an extremely
flammable fuel. If spilled
and ignited by a spark or
other ignition source, it
can cause fire and serious
burn injury or property
damage. Use extreme caution when
handling gasoline or fuel mix. Do not
smoke or bring any fire or flame near the
fuel or the power tool. Note that
combustible fuel vapor may escape from
the fuel system.
Fueling Instructions
!Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before
refueling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
In order to reduce the risk of burns and
other personal injury from escaping gas
vapor, remove the fuel filler cap on your
power tool carefully so as to allow any
pressure build-up in the tank to release
slowly. Never remove the fuel filler cap
while the engine is running.
Select bare ground for fueling and move
at least 10 feet (3 m) from the fueling
spot before starting the engine. Wipe off
any spilled fuel before starting your
machine.
!Warning!
Check for fuel leakage while refueling
and during operation. If fuel leakage is
found, do not start or run the engine until
the leak is fixed and any spilled fuel has
been wiped away. Take care not to get
fuel on your clothing. If this happens,
change your clothing immediately.
Different models may be equipped with
different fuel caps.
Cap with grip
!Warning!
In order to reduce the risk of fuel spillage
and fire from an improperly tightened
fuel cap, correctly position and tighten
the fuel cap in the fuel tank opening.
To do this with this STIHL
cap, raise the grip on the
top of the cap until it is
upright at a 90° angle.
Insert the cap in the fuel
tank opening with the
triangular marks on the grip of the cap
and on the fuel tank opening lining up.
Using the grip, turn the cap firmly
clockwise as far as it will go (approx. a
quarter turn).
Fold the grip flush with the
top of the cap. If the grip
does not lie completely
flush with the cap and the
detent on the grip does
not fit in the
corresponding recess in the filler neck,
the cap is not properly seated and
tightened and you must repeat the
above steps.
7FS 55
English / USA
Screw cap
!Warning!
Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill
quantities of fuel. In order
to reduce the risk of fuel
spillage and fire, tighten the fuel filler cap
by hand as securely as possible.
Before Starting
!Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger interlock, stop switch, cutting
attachment, deflector and harness. The
throttle trigger must move freely and
always spring back to the idle position.
Never attempt to modify the controls or
safety devices. Never use a power tool
that is damaged or not properly
maintained.
!Warning!
Do not attach any cutting attachment to
a unit without proper installation of all
required parts. Failure to use the proper
parts may cause the blade or head to fly
off and seriously injure the operator or
bystanders.
!Warning!
The cutting attachment must be properly
tightened and in safe operating
condition. Inspect for loose parts (nuts,
screws, etc.) and for cracked or
damaged heads or cracked, bent,
warped or damaged blades. Replace
damaged heads or blades before using
the power tool. Always keep blades
sharp.
Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, grease
or resin in order for you to maintain a firm
grip and properly control your power
tool.
!Warning!
Check that the spark plug boot is
securely mounted on the spark plug – a
loose boot may cause arcing that could
ignite combustible fumes and cause a
fire.
! Warning!
To reduce the risk
of personal injury
to the operator
from blade or line
contact and
thrown objects, make sure your unit is
equipped with the proper deflector,
handle and harness for the type of
cutting attachment being used (see
chart in the chapter on "Approved
Combinations of Cutting Attachment,
Deflector, Handle and Harness").
As can be seen in that chart, some
cutting attachments may require you to
change your deflector, handle and/or
harness.
Keep the deflector (and the attached
skirt where appropriate) adjusted
properly at all times (see chapters on
"Mounting the Deflector" and "Mounting
the Cutting Attachments" of your
instruction manual).
8
FS 55
English / USA
.
A
Arrows on the deflector (A) (as seen
from the underside) show the correct
direction of rotation of the cutting
attachment. When viewed from above,
however, the cutting attachment rotates
counterclockwise.
Adjust carrying harness and hand grip to
suit your size before starting work. The
machine should be properly balanced as
specified in your instruction manual for
proper control and less fatigue in
operation. To be better prepared in case
of an emergency, practice releasing the
unit from the harness as quickly as
possible.
Starting
Start the engine at least 10 feet
(3 meters) from the fueling spot,
outdoors only.
For specific starting instructions, see the
appropriate section of your manual.
Place the power tool on firm ground or
000BA006 KN
other solid surface in an open area.
Maintain good balance and secure
footing.
!Warning!
To reduce the risk of injury from blade or
line contact, be absolutely sure that the
cutting attachment is clear of you and all
other obstructions and objects, including
the ground, because when the engine
starts at starting-throttle, engine speed
will be fast enough for the clutch to
engage and move the cutting
attachment.
Once the engine has started,
immediately blip the throttle trigger,
which should release the starting throttle
and allow the engine to slow down to
idle.
With the engine running only at idle,
attach the power tool to the spring hook
of your harness (see appropriate
chapter of this manual).
!Warning!
Your power tool is a one-person
machine. Do not allow other persons in
the general work area, even when
starting.
!Warning!
To reduce the risk of injury from loss of
control, do not attempt to “drop start”
your power tool.
!Warning!
When you pull the starter grip, do not
wrap the starter rope around your hand.
Do not let the grip snap back, but guide
the starter rope to rewind it properly.
Failure to follow this procedure may
result in injury to your hand or fingers
and may damage the starter
mechanism.
9FS 55
English / USA
Important Adjustments
!Warning!
To reduce the risk of personal injury from
loss of control or contact with the
running cutting attachment, do not use
your unit with incorrect idle adjustment.
At correct idle speed, the cutting
attachment should not move. For
directions on how to adjust idle speed,
see the appropriate section of your
instruction manual.
If you cannot set the correct idle speed,
have your STIHL dealer check your
power tool and make proper
adjustments and repairs.
During Operation
Holding and controlling the power
tool
Always hold the unit firmly with both
hands on the handles while you are
working. Wrap your fingers and thumbs
around the handles.
!Warning!
Never attempt to operate
your power tool with one
hand. Loss of control of
the power tool resulting in
serious or fatal injury may
result. To reduce the risk
of cut injuries, keep hands and feet away
from the cutting attachment. Never
touch a moving cutting attachment with
your hand or any other part of your body.
002BA055 KN
!Warning!
Do not overreach. Keep proper footing
and balance at all times. Special care
must be taken in slippery conditions (wet
ground, snow) and in difficult, overgrown
terrain. Watch for hidden obstacles such
as tree stumps, roots and ditches to
avoid stumbling. For better footing, clear
002BA054 KN
away scrub and cuttings. Be extremely
cautious when working on slopes or
uneven ground.
!Warning
To reduce the risk of injury from loss of
control, never work on a ladder or on any
other insecure support. Never hold the
cutting attachment above waist height.
10
FS 55
English / USA
Working conditions
Operate and start your power tool only
outdoors in a well ventilated area.
Operate it under good visibility and
daylight conditions only. Work carefully.
!Warning!
As soon as the engine is
running, this product
generates toxic exhaust
fumes containing
chemicals such as
unburned hydrocarbons
(including benzene) and carbon
monoxide that are known to cause
respiratory problems, cancer, birth
defects, or other reproductive harm.
Some of the gases (e.g. carbon
monoxide) may be colorless and
odorless. To reduce the risk of serious or
fatal injury/illness from inhaling toxic
fumes, never run the machine indoors or
in poorly ventilated locations.
!Warning!
If the vegetation being cut or the
surrounding ground is coated with a
chemical substance (such as an active
pesticide or herbicide), read and follow
the instructions and warnings that
accompanied the substance at issue.
!Warning!
Inhalation of certain dusts, especially
organic dusts such as mold or pollen,
can cause susceptible persons to have
an allergic or asthmatic reaction.
Substantial or repeated inhalation of
dust and other airborne contaminants, in
particular those with a smaller particle
size, may cause respiratory or other
illnesses. Control dust at the source
where possible. Use good work
practices, such as operating the unit so
that the wind or operating process
directs any dust raised by the power tool
away from the operator. Follow the
recommendations of EPA/OSHA/
NIOSH and occupational and trade
associations with respect to dust
(“particulate matter”). When the
inhalation of dust cannot be substantially
controlled, i.e., kept at or near the
ambient (background) level, the
operator and any bystanders should
wear a respirator approved by NIOSH/
MSHA for the type of dust encountered.
Operating instructions
!Warning!
Do not operate your power tool using the
starting throttle lock, as you do not have
control of the engine speed.
In the event of an emergency, shut off
the engine immediately – move the slide
control / stop switch to 0 or STOP.
!Warning!
The cutting attachment
continues to rotate for a
short period after the
throttle trigger is released
(flywheel effect).
!Warning!
The rotating cutting attachment may
fling foreign objects directly or by
ricochet a great distance.
11FS 55
English / USA
15m (50ft)
To reduce the risk of eye and other injury
always wear proper eye protection (see
the chapter on “Proper Clothing“) and
ensure that bystanders are at least 50
feet (15 m) away. To reduce the risk of
damage to property, also maintain this
distance from such objects as vehicles
or windows. Any coworkers who must be
in the restricted area should also wear
goggles or protective glasses. Stop the
engine immediately if you are
approached.
!Warning!
Before you start work,
examine the area for
stones, glass, fence wire,
metal, trash or other solid
objects. The cutting
attachment could throw
objects of this kind.
!Warning!
This trimmer/brushcutter is normally to
be used at ground level with the cutting
attachment parallel to the ground. Use of
a trimmer/brushcutter above ground
level or with the cutting attachment
perpendicular to the ground may
increase the risk of injury, since the
cutting attachment is more fully exposed
and the power tool may be more difficult
to control.
!Warning!
During cutting, check the tightness and
the condition of the cutting attachment at
regular short intervals with the engine
and attachment stopped. If the behavior
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 blade or head for
cracks, wear and damage.
!Warning!
A loose blade or head may vibrate,
crack, break or come off the trimmer/
brushcutter, 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
blade or 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/brushcutter with a loose
cutting attachment.
!Warning!
Replace a cracked, damaged or wornout 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.
12
FS 55
English / USA
!Warning!
When using rigid blades, avoid cutting
close to fences, sides of buildings, tree
trunks, stones or other such objects that
could cause the power tool to kick out or
could cause damage to the blade.
STIHL recommends use of the nylon line
heads for such jobs. In addition, be alert
to an increased possibility of ricochets in
such situations.
!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!
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.
!Warning!
To reduce the risk of fire and burn injury,
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.
!Warning!
Never modify your muffler. The muffler
could be damaged and cause an
increase in heat radiation or sparks,
thereby increasing the risk of fire and
burn injury. You may also permanently
damage the engine. Have your muffler
serviced and repaired by your STIHL
servicing dealer only.
Catalytic converter
!Warning!
Some STIHL power tools
are equipped with a
catalytic converter, which
is designed to reduce the
exhaust emissions of the
engine by a chemical
process in the muffler. Due to this
process, the muffler does not cool down
as rapidly as conventional mufflers when
the engine returns to idle or is shut off.
To reduce the risk of fire and burn
injuries, the following specific safety
precautions must be observed.
13FS 55
English / USA
!Warning!
Since a muffler with a catalytic converter
cools down less rapidly than conventional mufflers, always set your power
tool down in the upright position and
never locate it where the muffler is near
dry brush, grass, wood chips or other
combustible materials while it is still hot.
!Warning!
An improperly mounted or damaged
cylinder housing or a damaged/
deformed muffler shell may interfere
with the cooling process of the catalytic
converter. 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 catalytic converter is furnished with
screens designed to reduce the risk of
fire from the emission of hot particles.
Due to the heat from the catalytic
reaction, these screens will normally
stay clean 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.
USING THE CUTTING
ATTAC HMENTS
For an illustration of the various cutting
attachments and instructions on proper
mounting see the chapter on "Mounting
the Cutting Attachments" in your
instruction manual.
!Warning!
To reduce the risk of severe or fatal
injury from blade contact and/or loss of
control, never attempt to use a metal
blade on an FS model for which it is not
authorized.
Using the Mowing Heads
Do not use with mowing line longer than
the intended length. With a properly
mounted deflector, the built-in linelimiting blade will automatically adjust
the line to its proper length.
Using the unit with an overly long nylon
cutting line increases the load on the
engine and reduces its operating speed.
This causes the clutch to slip
continuously and results in overheating
and damage to important components
(e.g. clutch, polymer housing
components). Such damage could,
among other things, cause the cutting
attachment to rotate at idle.
000BA015 KN
Mowing heads are to be used only on
trimmer/brushcutters equipped with a
line-limiting blade in the deflector in
order to keep the line at the proper
length (see "Parts and Controls" chapter
in your instruction manual).
If the lawn edges are planted with trees
or bordered by a fence etc., it is best to
use a nylon line head. It achieves a
"softer" cut with less risk of damaging
tree bark etc. than polymer blades.
14
FS 55
English / USA
However, the polymer-bladed STIHL
PolyCut produces a better cut if there
are no plants along the edge of the lawn.
Sharpening is not necessary, and worn
polymer blades are easily replaced.
!Warning!
To reduce the risk of serious injury,
never use wire or metal-reinforced line
or other material in place of the nylon
cutting lines. Pieces of wire could break
off and be thrown at high speed toward
the operator or bystanders.
STIHL SuperCut mowing head
Fresh line is advanced automatically.
Frayed line is replaced by a simple
adjustment (see instruction sheet
supplied with mowing head).
STIHL TrimCut mowing head
Frayed line is replaced by a simple
adjustment (see instruction sheet
supplied with mowing head).
STIHL AUTOCUT mowing head
Nylon cutting cord advances
automatically when tapped against the
ground (TapAction).
STIHL PolyCut mowing head
Uses either nylon lines or nonrigid,
pivoting polymer blades.
!Warning!
Three rectangular wear limit marks are
applied to the base (periphery) of the
PolyCut. To reduce the risk of serious
injury from breakage of the head or
blades, the PolyCut must not be used
when it has worn as far as one of these
marks. It is important to follow the
maintenance instructions supplied with
the head.
STIHL FixCut mowing head
Uses pre-cut lengths of nylon line.
Observe wear indicators.
002BA177 KN
Do not continue using the mowing head
if the raised moldings (1) on the base are
missing or worn – see right illustration
above. The mowing head may otherwise
shatter and flying objects could result in
injury to the operator or bystanders.
Install a new mowing head.
15FS 55
English / USA
Risk of Kickout (Blade Thrust)
with All Rigid Cutting Blades
!Warning!
Kickout (blade thrust) is the sudden and
uncontrolled motion towards the
operator's right or rear that can occur
when the shaded area (especially the
darkly shaded area) of a rotating blade
comes in contact with a solid rigid object
like a tree, rock, bush or wall. The rapid
counterclockwise rotation of the blade
may be stopped or slowed, and the
cutting attachment may be thrown to the
right or to the rear.
This kickout (blade thrust) may cause
loss of control of the power tool and may
result in serious or fatal injury to the
operator or bystanders. To reduce the
risk of injury, extreme caution should be
used when cutting with the shaded area
of any rigid blade.
Using the Grass Cutting Blade
002BA135 KN
All kinds of grass and weeds can be
easily cut with the grass cutting blade.
The power tool is swept in an arc similar
to a scythe.
!Warning!
To reduce the risk of serious or fatal
injury from blade breakage, never
attempt to use this blade to cut woody
materials.
The 4-tooth grass cutting blade is
intended to cut grass and weeds. It has
4 cutting knives with cutting edges on
both sides, i.e. front and rear. When the
cutting edges on one side become dull,
the blade can be turned over to utilize
the cutting edges on the other side.
The 8-tooth grass cutting blade is
recommended for cutting fern or reed.
Both types of grass cutting blade have to
be resharpened when all cutting edges
are dull.
000BA020 KN
16
FS 55
English / USA
MAINTENANCE, REPAIR AND
STORING
Maintenance, replacement, or repair
of the emission control devices and
systems may be performed by any
nonroad engine repair establishment
or individual. However, if you make a
warranty claim for a component
which has not been serviced or
maintained properly or if
nonapproved replacement parts were
used, STIHL may deny coverage.
!Warning!
Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.
Strictly follow the maintenance and
repair instructions in the appropriate
sections of your instruction manual.
!Warning!
Always stop the engine and make sure
that the cutting attachment is stopped
before doing any maintenance or repair
work or cleaning the power tool. Do not
attempt any maintenance or repair work
not described in your instruction manual.
Have such work performed by your
STIHL servicing dealer only.
Wear gloves when handling or
performing maintenance on blades.
!Warning!
Use the specified spark plug, and make
sure it and the ignition lead are always
clean and in good condition. Always
press spark plug boot snugly onto spark
plug terminal of the proper size. (Note: If
terminal has detachable SAE adapter
nut, it must be securely attached.) A
loose connection between the spark
plug and the ignition wire connector in
the boot may create arcing that could
ignite combustible fumes and cause a
fire.
!Warning!
Never test the ignition system with the
spark plug boot removed from the spark
plug or with a removed spark plug, since
uncontained sparking may cause a fire.
!Warning!
Do not operate your power tool if the
muffler is damaged, missing or modified.
An improperly maintained muffler will
increase the risk of fire and hearing loss.
If your muffler was equipped with a
spark-arresting screen to reduce the risk
of fire, never operate your power tool if
the screen is missing or damaged.
Remember that the risk of forest fires is
greater in hot or dry weather.
!Warning!
Never repair damaged cutting attachments by welding, straightening or
modifying the shape. This may cause
parts of the cutting attachment to come
off and result in serious or fatal injuries.
Keep blades sharp. Tighten all nuts,
bolts and screws, except the carburetor
adjustment screws, after each use.
Store the power tool in a dry and high or
locked location out of reach of children.
Before storing for longer than a few
days, always empty the fuel tank. See
chapter "Storing the Machine" in the
instruction manual.
17FS 55
English / USA
Approved Combinations of Mowing Tool, Deflector, Handle
and Harness
Mowing tools
1 STIHL SuperCut 20-2
2 STIHL AutoCut C 25-2
3 STIHL AutoCut 25-2
4 STIHL TrimCut 30-2
5 STIHL PolyCut 20-3
6 STIHL FixCut 25-3
7 Grass cutting blade 230-4
8 Grass cutting blade 230-8
Deflectors
9 Deflector for mowing heads
10 Deflector for all mowing tools
with
11 Skirt and blade
12 Deflector for all mowing tools
without skirt and blade
Handles
13 Loop handle
14 Loop handle with
15 Barrier bar
16 Bike handle
Harnesses
17 Shoulder strap may be used
18 Shoulder strap must be used
19 Full harnesss may be used
Equipment
The complete unit includes:
- Mowing tool
- Deflector
- Handle
- Harness (bike unit only)
Select the correct combination from
the table according to the mowing
tool you intend to use. Read the table
horizontally from left to right. Other
combinations, e.g. reading the table
diagonally, are not permitted.
Warning!
To reduce the risk of injury from
thrown objects and blade contact,
never operate your unit without the
proper deflector for the mowing
attachment being used. To reduce the
risk of injury from loss of control
and / or contact with the mowing tool,
make sure your unit is equipped with
a proper handle and harness for the
type of mowing attachment beeing
used.
Warning!
Stihl brushcutters with a loop handle
without barrier bar may be used only
with the above mentioned mowing
head with nylon line or plastic blades.
Other plastic or metal mowing tool
may only be used on brushcutters
with a bike-handle or loop-handle
with barrier bar in order to reduce the
risk of personal injury through
contact with the mowing tool.
18
FS 55
English / USA
002
0
0
0
002BA003 K
002BA001 K
0
002BA005 K
Mowing tools Deflectors Handles Harnesses/Straps
1
681FK003
13
BA002 K
2
9
3
681FK006
681FK023
14
15
17
02BA125 KN
4
681FK037 KN
11
5
681FK011
10
681BA002 KN
16
02BA001 K
6
681FK111 KN
7
15
18 19
02BA127 KN
14
8
681FK014
12
681FK021
16
18 19
02BA127 KN
19FS 55
English / USA
Mounting the Bike Handle
5
11
A
7
6
4
2
3
1
Fitting the handlebar
: Place the clamp (1) and handle
support (2) on the drive tube (3).
: Position the handlebar (4) in the
handle support – the rubber grip (5)
must be on the left (viewed from
engine).
: Place clamp (6) on handle support.
: Insert screws (7) in the holes and
screw down as far as stop in clamp.
233BA025 KN
: Secure handlebar (4) on the drive
tube (3) at distance (A) of approx.
15 cm (6 in) from the powerhead.
: Align the handlebar.
: Tighten down the screws firmly.
4
3
10
8
12
9
4
12
233BA018 KN
Fitting the control handle
: Release the screw (8) and remove it
with the washer. The nut (9) remains
in the control handle (10).
: Push the control handle onto the
handlebar (4) – the throttle trigger
(11) must point towards the
gearhead.
: Line up the holes (12).
: Fit screw and washer in control
handle and tighten down firmly.
233BA038 KN
20
* see “Guide to Using this Manual”
FS 55
Mounting the Loop Handle
English / USA
13
14
14
13
Fitting the throttle cable
Do not kink the throttle cable - make
sure the throttle trigger moves freely.
: Push the throttle cable (13) into the
retainer (14).
233BA027 KN
2
Loop handle with barrier bar
: Insert square nuts (1) in the
barrier bar (2).
: Line up the holes.
4
2
3
1
5
1
6
7
002BA098 KN
: Place the clamp (3) in the loop
handle (4) and position them both
against the drive tube (5).
: Fit the clamp (6) and place the
barrier bar (2) in position.
Note correct position.
: Line up the holes.
: Insert screws (7) in holes and screw
them into the barrier bar as far as
stop.
: Go to “Securing the loop handle”.
002BA099 KN
21FS 55
English / USA
Fitting the Carrying Eye
8
8
7
7
4
1
A
9
4
3
5
6
1
1
Loop handle without barrier bar
: Place the clamp (3) in the loop
handle (4) and position them both
against the drive tube (5).
: Fit the clamp (6) and line up the
holes.
: Fit washers (7) on screws (8).
: Insert screws (8) in holes and screw
on the square nuts (1) as far as
stop.
: Go to “Securing the loop handle”.
10
002BA136 KN
Securing the loop handle
: Secure the loop handle (4)
approx. 8”/20cm (A) forward of
the control handle (9).
: Line up the loop handle.
: Tighten down the screws firmly –
lock the nuts if necessary.
10= Sleeve*
1
2
002BA147 KN
: For position of carrying eye
"Parts and Controls"
: Place the clamp (1) with the
tapped hole on the left-hand side
of the drive tube.
: Squeeze the two ends of the clamp
together and hold in that position.
: Insert M 6 x 14 screw (2).
: Line up the carrying eye.
: Tighten down the screw firmly.
1)
002BA142 KN
see
22
* see “Guide to Using this Manual”
1) Included as standard or available as
special accessory
FS 55
English / USA
Mounting the Deflector
1
3
2
3
Mounting the deflector
1 = Deflector approved for all cutting
tools
2 = Deflector approved for use with
mowing heads only
: Place the deflector on the
gearhead.
: Fit the plate (3) and line it up.
: Insert M 5 x 18 screws and tighten
down firmly.
4
4
1
5
002BA102 KN
Fitting skirt and blade
These parts must be fitted to the
deflector (1) when you use a
mowing head:
: Slide the lower guide slot of the
skirt (4) onto the deflector (1) – it
must snap into position.
: Push the blade (5) into the upper
guide slot on the skirt and line it up
with the first hole.
: Fit the screw and tighten it down
firmly.
Mounting the Cutting Tools
Preparations
: Lay your brushcutter on its back
with the gearhead facing upward.
Mounting Hardware
for Cutting Tools
002BA103 KN
The mounting hardware supplied
depends on the cutting tool that comes
as original equipment with the new
brushcutter.
Mounting hardware is not packed
with the machine
Only mowing heads may be
mounted.
002BA104 KN
23FS 55
English / USA
Mounting hardware is packed with
the machine
3
Mowing heads and metal cutting
tools may be mounted.
4
5
1
2
: Pull the hose (1) (protector for
shipping) off the shaft (2).
: Go to "Mounting the Mowing Head".
If you want to mount a metal cutting
tool in place of a mowing head, you
will need the following additional
parts: Nut (3), rider plate (4) and
thrust washer (5) (special
accessories).
Mounting hardware is loose
: Pull the hose (1) (protector for
shipping) off the shaft (2).
The nut (3), rider plate (4) and thrust
washer (5) are in the parts kit
supplied with the machine.
: Go to "Mounting the Mowing Head"
or "Mounting Metal Cutting Tools".
Mounting hardware is secured to
002BA164 KN
gearhead
: Go to "Removing Mounting
Hardware"
Removing Mounting Hardware
: Block the shaft – see next section
on "Blocking the Output Shaft".
: Use the combination wrench (6)
(supplied with machine or available
as special accessory) to unscrew
the nut (3) clockwise (left-hand
thread) from the shaft (2).
: Pull the thrust washer (5) off the
shaft (2).
24
FS 55
The rider plate (4) is in the parts kit
supplied with the machine.
: Go to "Mounting the Mowing Head"
or "Mounting Metal Cutting Tools".
Blocking the Output Shaft
English / USA
2
8
7
: Insert the stop pin or screwdriver (7)
(supplied with machine or available
as special accessories) in the hole
(8) in the gearhead as far as stop –
apply slight pressure.
: Rotate nut or cutting tool on the
shaft (2) until the stop pin slips into
position and blocks the shaft.
7
1
002BA166 KN
Mounting the Mowing Head
Keep instruction sheet for mowing head
in a safe place.
: Screw the
STIHL SuperCut 20-2,
STIHL AutoCut 25-2,
STIHL AutoCut C 25-2,
STIHL TrimCut 30-2,
STIHL PolyCut 20-3
counterclockwise onto the shaft (1)
as far as stop.
: Block the output shaft.
: Tighten down the mowing head.
Remove the tool used to block the
shaft.
002BA081 KN
STIHL FixCut 25-2
: Place the mowing head on the
thrust plate (2).
Collar (arrows) must locate in the
mowing head’s mounting hole
: Push the thrust washer (3) over the
shaft (1) so that it locates against
the base.
: Block the output shaft.
: Screw the mounting nut (4) with the
combination wrench (5)
counterclockwise on to the output
shaft and tighten down firmly.
Remove the tool used to block the
shaft.
25FS 55
English / USA
Removing the Mowing Head
: Block the output shaft.
STIHL SuperCut 20-2,
STIHL AutoCut 25-2,
STIHL AutoCut C 25-2,
STIHL TrimCut 30-2,
STIHL PolyCut 20-3
: Unscrew the mowing head
clockwise.
STIHL FixCut 25-2
: Use the combination wrench to
unscrew the mounting nut clockwise
from the output shaft
If the mounting nut is too loose, fit a
new one
Adjusting Nylon Line
STIHL SuperCut
Fresh line is advanced automatically if
remaining line is still min. 2 1/2" (6 cm)
long. The blade on the deflector trims
overlong line to the correct length.
STIHL AutoCut
: Hold the rotating mowing head
above the ground – tap it on the
ground once – about 1 1/4" (3 cm)
fresh line is advanced.
The blade on the deflector trims
overlong line to the correct length –
avoid tapping head more than once at a
time.
Line feed operates only if both lines
still have a minimum length of 1"
(2.5 cm).
All other mowing heads
Refer to the instructions supplied with
the mowing head.
To reduce the risk of injury, always
shut off the engine before adjusting
the nylon line by hand.
Replacing Nylon Line or Cutting
Blades
Refer to the instructions supplied with
the mowing head.
26
FS 55
1
Mounting metal cutting tools
Remove the skirt and blade from
the deflector before mounting Grass
cutting blade 230-4 (1) or Grass
cutting blade 230-8 (2).
See chapter “Mounting the Deflector”
8
6
2
5
7
4
: Lay your brushcutter on its back
with the gearhead facing upward.
Cutting edges of (1) may point in either
direction.
Cutting edges of (2) must point
clockwise.
3
English / USA
: Place the cutting tool (3) on the
thrust plate (4).
Collar (see arrow) must locate in
cutting tool’s mounting hole.
: Slip thrust washer (5) and rider plate
(6) over the output shaft (7).
: Block the output shaft.
: Screw the mounting nut (8) onto the
output shaft counterclockwise and
tighten down firmly.
If the mounting nut is too loose, fit a
new one.
Removing metal cutting tool
: Block the output shaft.
002BA120 KN
: Unscrew the mounting nut
clockwise.
: Take the parts off the shaft - do not
remove the thrust plate (4).
Direction of rotation is marked by
arrow on inside of mowing head
deflector.
27FS 55
English / USA
Fuel
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of highquality gasoline and quality two-stroke
air cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2). If
the octane rating of the mid-grade
gasoline in your area is lower, use
premium unleaded fuel.
Fuel with a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
nationally recognized high-quality
unleaded gasoline!
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke
engine oils that are designed for use
only in air cooled two-cycle engines.
We recommend STIHL 50:1 two-stroke
engine oil since it is specially formulated
for use in STlHL engines.
Do not use BIA or TCW rated (twostroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chainsaws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the canister from
your vehicle and place the canister on
the ground before filling. Do not fill fuel
canisters that are sitting in or on a
vehicle.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The machine‘s fuel tank and the canister
in which fuel mix is stored should be
cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 3 months of storage.
Store in approved fuel-canisters only.
When mixing, pour oil into the canister
first, and then add gasoline. Close the
canister and shake it vigorously by hand
to ensure proper mixing of the oil with
the fuel.
Gasoline
US gal. US fl.oz
12.6
2 1/2 6.4
512.8
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
Oil (STIHL 50:1 or
equivalent high-quality oils)
28
FS 55
English / USA
Fueling
Before fueling, clean the filler cap and
the area around it to ensure that no dirt
falls into the tank.
Always thoroughly shake the mixture in
the canister before fueling your
machine.
In order to reduce the risk of burns
or other personal injury from
escaping gas vapor and fumes,
remove the fuel filler cap carefully
so as to allow any pressure build-up
in the tank to release slowly.
After fueling, tighten fuel cap as
securely as possible by hand.
Fitting the Harness
232BA046 KN
The type and style of harness depend on
the market.
Shoulder strap*
: Put on the shoulder strap (1).
: Adjust length until the spring hook
(2) is about a hand’s width below
your right hip.
: Balance the brushcutter.
The use of the shoulder strap is
described in chapter “Approved
Combinations of Cutting Tool, Deflector,
Handle and Harness”.
Full harness
: Put on the full harness (1).
: Adjust length until the spring hook
(2) is about a hand’s width below
your right hip.
: Balance the brushcutter.
The use of the harness is described in
chapter “Approved Combinations of
Cutting Tool, Deflector, Handle and
Harness”.
29FS 55
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