Stihl FS 70 User manual

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STIHL FS 70
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.
Instruction Manual
Manual de instrucciones

Instruction Manual
1 - 40
Manual de
instrucciones
41 - 86

Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2009 0458-570-8621-A. M16-75.L09.CP. 0000001656_006_GB
FS 70 RC
English
1
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Contents
Allow only persons who fully 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 and follow the
maintenance and safety precautions in
chapter "Safety Precautions and
Working Techniques" before using your
trimmer/brushcutter. For further
information you can go to
www.stihlusa.com.
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 high-
speed 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.
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 2
Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness 15
Mounting the Loop Handle 16
Mounting the Deflector 17
Mounting the Cutting Attachment 18
Fuel 20
Fueling 21
Fitting the Harness 22
Starting / Stopping the Engine 23
Operating Instructions 25
Cleaning the Air Filter 25
Engine Management 26
Adjusting the Carburetor 26
Spark Plug 27
Engine Running Behavior 28
Rewind Starter 29
Storing the Machine 29
Sharpening Metal Cutting Blades 29
Inspections and Maintenance by
Dealer 30
Maintenance and Care 31
Main Parts 32
Specifications 34
Special Accessories 35
Maintenance and Repairs 35
STIHL Incorporated Federal
Emission Control Warranty
Statement 35
STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 37
Trademarks 39

FS 70 RC
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Pictograms
All the pictograms attached to the
machine are shown and explained in this
manual.
Symbols in Text
Many operating and safety instructions
are supported by illustrations.
The individual steps or procedures
described in the manual may be marked
in different ways:
NA 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:
NLoosen the screw (1).
NLever (2) ...
In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are marked with the
symbols and signal words described
below:
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. Therefore,
some changes, modifications and
improvements may not be covered in
this manual. If the operating
characteristics or the appearance of
your machine differ from those
described in this manual, please contact
your STIHL dealer for assistance.
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.
Guide to Using this Manual
Danger!
Indicates an imminent risk of severe or
fatal injury.
Warning!
Indicates a hazardous situation which, if
not avoided, could result in severe or
fatal injury.
Caution!
Indicates a risk of property damage,
including damage to the machine or its
individual components.
Safety Precautions and
Working Techniques
Because a trimmer/
brushcutter is a high-
speed, fast-cutting power
tool sometimes equipped
with sharp cutting blades,
special safety precau-
tions must be observed to
reduce the risk of per-
sonal 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.

FS 70 RC
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FS models with an "R" on the nameplate
were originally configured (at the time of
distribution) as a trimmer with a loop
handle.
Have your STIHL dealer show you how
to operate your power tool. Observe all
applicable local safety regulations,
standards and ordinances.
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.
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.
Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.
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.
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
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, har-
ness and deflector for the type of cutting
attachment you are using. Use only cut-
ting attachments that are specifically
authorized by STIHL for use on your FS
model.
Warning!
Do not lend or rent your power tool with-
out the instruction manual. Be sure that
anyone using it understands the infor-
mation contained in this manual.
Warning!
The use of this machine may be hazard-
ous. If the rotating line or blade comes in
contact with your body, it will cut you.
When it comes in contact with solid for-
eign objects such as rocks or bits of
metal, it may fling them directly or by ric-
ochet 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.
Warning!
Do not use it for other purposes, since
misuse may result in personal injury or
property damage, including 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.
Warning!
To reduce the risk of injury to bystand-
ers 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 unauthor-
ized persons do not use it.
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 dis-
ease (Raynaud's phenomenon) or
carpal tunnel syndrome.

FS 70 RC
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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.
–Wear gloves and keep your hands
warm.
–Keep the AV system well
maintained. A power tool with loose
components or with damaged or
worn AV elements will tend to have
higher vibration levels.
–Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressure. 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.
Proper Clothing
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.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
Warning!
The ignition system of the STIHL unit
produces an electromagnetic field of a
very low intensity. This field may inter-
fere with some pacemakers. To reduce
the risk of serious or fatal injury, persons
with a pacemaker should consult their
physician and the pacemaker manufac-
turer before operating this tool.
Warning!
To reduce the risk of injury, the operator
should wear proper protective apparel.
To reduce the risk of
injury to your eyes never
operate your power tool
unless wearing goggles
or properly fitted protec-
tive glasses with
adequate top and side
protection complying with
ANSI Z 87.1 (or your
applicable national stand-
ard.) 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.
Always wear gloves
when handling the
machine and metal
blades. Heavy-duty, non-
slip 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.
Avoid loose-fitting jack-
ets, 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.

FS 70 RC
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THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts and Controls."
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
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.
Fuel
Your STIHL power tool uses an oil-
gasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual.)
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended. Do
not wear sandals or go
barefoot.
Wear an approved safety
hard hat to reduce the
risk of injury to your head
when there is a danger of
head injuries.
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 unauthor-
ized 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 Har-
ness" in the instruction manual or the
STIHL "Power Tools and Accessories"
catalog.
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
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.)
Warning!
Gasoline is an extremely
flammable fuel. If spilled
and ignited by a spark or
other ignition source, it
can cause fire and seri-
ous 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.

FS 70 RC
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Fueling Instructions
In order to reduce the risk of burns and
other personal injury from escaping gas
vapor and fumes, 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.
Cap with Grip
Before Starting
Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, fuel mix,
grease or resin in order for you to
maintain a firm grip and properly control
your power tool.
Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before refu-
eling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
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.
Warning!
In order to reduce the risk of fuel spill-
age 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 tri-
angular 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 com-
pletely flush with the cap
and the detent on the grip
does not fit in the corre-
sponding recess in the
filler opening, the cap is
not properly seated and
tightened and you must
repeat the above steps.
Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, momentary stop switch,
cutting attachment, deflector and har-
ness. 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 prop-
erly 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 prop-
erly tightened and in safe operating
condition. Inspect for loose parts (nuts,
screws, etc.) and for cracked or dam-
aged heads or cracked, bent, warped or
damaged blades. Replace damaged
heads or blades before using the power
tool. Always keep blades sharp.
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.

FS 70 RC
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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.)
Arrows on the deflector (A) and limit
stop (B) (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
For specific starting instructions, see the
appropriate section of your manual.
Place the power tool on firm ground or
other solid surface in an open area.
Maintain good balance and secure
footing.
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!
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, han-
dle 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".)
Warning!
Start the engine at least 10 feet (3 m)
from the fueling spot, outdoors only.
A
000BA006 KN
B
000BA007 KN
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, includ-
ing 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.
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.

FS 70 RC
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Important Adjustments
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, keeping the
handles cradled between your thumb
and forefinger. Keep your hands in this
position to have your power tool under
control at all times. Make sure your
trimmer handles and grips are in good
condition and free of moisture, pitch, oil,
fuel mix or grease
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!
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.
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 attach-
ment should not move. For directions on
how to adjust idle speed, see the appro-
priate section of your instruction
manual.
Warning!
This unit is equipped with an ignition
system that is normally in operational
readiness. After the setting lever is used
to stop the engine, it automatically
springs back to the "on" position. If the
engine is warm, it may be possible to
start it by simply pulling the starter rope,
with no further adjustments. To reduce
the risk of injury, be particularly alert to
keep children away from the unit.
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.
002BA257 KN
002BA273 KN
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 attach-
ment with your hand or any other part of
your body.
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, over-
grown terrain. Watch for hidden
obstacles such as tree stumps, roots
and ditches to avoid stumbling. For bet-
ter footing, clear away scrub and
cuttings. Be extremely cautious when
working on slopes or uneven ground.

FS 70 RC
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Operating Instructions
In the event of an emergency, switch off
the engine immediately – move the slide
control / momentary stop switch to 0or
STOP.
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!
As soon as the engine is
running, this product
generates toxic exhaust
fumes containing chemi-
cals, such as unburned
hydrocarbons (including
benzene) and carbon monoxide, that
are known to cause respiratory prob-
lems, cancer, birth defects, or other
reproductive harm. Some of the gases
(e.g. carbon monoxide) may be color-
less and odorless. To reduce the risk of
serious or fatal injury/illness from inhal-
ing toxic fumes, never run the machine
indoors or in poorly ventilated locations.
Warning!
If the vegetation being cut or the sur-
rounding 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. Sub-
stantial or repeated inhalation of dust
and other airborne contaminants, in par-
ticular those with a smaller particle size,
may cause respiratory or other ill-
nesses. Control dust at the source
where possible. Use good work prac-
tices, 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 recom-
mendations of EPA/OSHA/NIOSH and
occupational and trade associations
with respect to dust ("particulate mat-
ter".) 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.
Warning!
Do not operate your power tool using
the starting throttle lock, as you do not
have control of the engine speed.
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 rico-
chet a great distance.
15m (50ft)

FS 70 RC
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10
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 per-
pendicular 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 trim-
mer/brushcutter, which may result in
serious or fatal injury. Make sure that
the cutting attachment is properly tight-
ened. 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 worn-
out head or a cracked, bent, warped,
damaged, dull or worn out blade imme-
diately, even if damage is limited to
superficial cracks. Such attachments
may shatter at high speed and cause
serious or fatal injury.
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 rico-
chets 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 clean-
ing. Grass, weeds, etc. should be
cleaned off the blade or from around the
head at regular intervals.
Warning!
To reduce the risk of unintentional rota-
tion 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 oper-
ation. 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.

FS 70 RC
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11
Catalytic Converter
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 ATTACHMENT
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.
Using the Mowing Heads
Do not use with mowing line longer than
the intended length. With a properly
mounted deflector, the built-in line-
limiting 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.
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.)
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.
Warning!
Some STIHL power tools
are equipped with a cat-
alytic converter, which is
designed to reduce the
exhaust emissions of the
engine by a chemical
process in the muffler. Due to this proc-
ess, 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 inju-
ries, the following specific safety
precautions must be observed.
Warning!
Since a muffler with a catalytic converter
cools down less rapidly than conven-
tional 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 cyl-
inder housing or a damaged / deformed
muffler shell may interfere with the cool-
ing 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.
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.
002BA354 KN

FS 70 RC
English
12
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.
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.
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.
STIHL FixCut mowing head
Uses pre-cut lengths of nylon line.
Observe wear indicators.
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.
Risk of Kickout (Blade Thrust) with
All Rigid Cutting Blades
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.
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 main-
tenance instructions supplied with the
head.
Warning!
If the wear limit marks are ignored, there
is a risk of the cutting attachment shat-
tering and flying parts injuring the
operator or bystanders. To reduce the
risk of accidents from shattered blades,
avoid contact with stones, metal and
similar solid objects. Check PolyCut
blades for cracks at regular intervals. If
a crack is found on one blade, always
replace all blades.
002BA177 KN
Warning!
Kickout (blade thrust) is the sudden and
uncontrolled motion towards the opera-
tor'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 coun-
terclockwise rotation of the blade may
be stopped or slowed, and the cutting
attachment may be thrown to the right or
to the rear.
002BA135 KN

FS 70 RC
English
13
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
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.
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.
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.
Strictly follow the maintenance and
repair instructions in the appropriate
sections of your instruction manual.
Wear gloves when handling or
performing maintenance on blades.
Warning!
To reduce the risk of serious or fatal
injury from blade breakage, never
attempt to use this blade to cut woody
materials.
002BA355 KN
Warning!
Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.
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 man-
ual. Have such work performed by your
STIHL servicing dealer only.
Warning!
Use the specified spark plug, and make
sure it and the ignition lead are always
clean and in good condition. Always
press the spark plug boot snugly onto
the spark plug terminal of the proper
size. (Note: If the terminal has a detach-
able 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 modi-
fied. 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 attach-
ments 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.

FS 70 RC
English
14
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.

FS 70 RC
English
15
Approved Combinations of Cutting Attachment, Deflector, Handle and Harness
Cutting Attachment Deflector Handle Harness
0414BA005 KN
12
5
7
3
8
12
11
9
16
14
4
15
16
6
10
13
12
13

FS 70 RC
English
16
Approved Combinations
The complete combination includes:
–Cutting Attachment
–Deflector
–Handle
–Harness
Select correct combination from the
table according to the cutting
attachment you intend to use. Read the
table horizontally from left to right.
Cutting Attachments
Mowing heads
1STIHL SuperCut 20-2 mowing head
2STIHL Autocut C 25-2 mowing head
3STIHL Autocut 25-2 mowing head
4STIHL TrimCut 31-2 mowing head
5STIHL PolyCut 20-3 mowing head
6STIHL FixCut 25-2 mowing head
Metal cutting attachments
7Grass cutting blade 230-4
8Grass cutting blade 230-8
Deflectors
9Deflector with blade for mowing
heads only
10 Deflector for grass cutting blades
only
Handles
11 Loop handle
12 Loop handle with
13 Barrier bar
Harnesses
14 Shoulder strap may be used
15 Shoulder strap must be used
16 Full harness may be used
A factory-new machines comes with the
loop handle aready mounted.
Using the barrier bar
A barrier bar may have to be mounted to
suit the tool you intend to use – see
"Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness."
The barrier bar comes standard with the
machine or is available as a special
accessory.
Non-metal grass cutting blades
are not approved.
Warning!
Based on the cutting attachment being
used:
Choose the proper deflector in order to
reduce the risk of injury from thrown
objects and contact with the cutting
attachment.
Make sure your unit is equipped with the
proper handle and harness in order to
reduce the risk of injury from loss of con-
trol and contact with the cutting
attachment: use grass cutting metal
blades on this unit only if equipped with
a bike handle or a loop handle with bar-
rier bar.
Do not use rigid plastic blades, brush
knifes or circular saw blades on this unit.
Mounting the Loop Handle
547BA004 KN547BA005 KN

FS 70 RC
English
17
Mounting the barrier bar
NFit the washer (1) on the M5x23
screw (2).
NHold the barrier bar (3) against the
loop handle and insert the screw
with washer.
NTighten down the screw (2) firmly.
Leave the barrier bar permanently
mounted to the loop handle.
Adjusting and securing the loop
handle
The loop handle can be adjusted to suit
the height and reach of the operator and
the application by changing
distance (A).
Recommended distance (A): about
14 in (35 cm)
NLoosen the screw on the handle.
NSlide the handle to the required
position.
NTighten down the screw so that the
handle cannot be rotated on the
drive tube.
Use the right deflector
Mounting the Deflector
Deflectors (1) and (2) are both mounted
to the gearbox in the same way.
(5,3 mm)
547BA031 KN
12
3
0.2 in
547BA007 KN
A
Mounting the Deflector
Deflector (1) is approved for
mowing heads only and must
therefore be mounted before
fitting a mowing head
Deflector (2) is approved for grass
cutting blades only and must
therefore be mounted before
fitting a grass cutting blade.
002BA262 KN
1
002BA263 KN
2

FS 70 RC
English
18
NPosition the deflector against the
gearbox so that the lug (3) engages
the recess (4) in the deflector.
NInsert the screw (5) and tighten it
down firmly.
The new machine comes from the
factory wirth the cutting attachment
already mounted.
Note the following points when mounting
other approved cutting attachments –
see "Approved Combinations of Cutting
Attachment, Deflector, Handle,
Harness":
Preparations
NLay your brushcutter on its back so
that the cutting attachment
mounting face is facing up.
Block the shaft.
The output shaft (1) must be blocked
with the stop pin (2) or screwdriver (2) to
mount or remove cutting attachments.
The stop pin or screwdriver (2) are either
supplied with the machine or available
as special accessories.
NInsert the stop pin (2) or
screwdriver (2) in the hole (3) in the
gearbox as far as stop – and apply
slight pressure.
NRotate nut or cutting attachment on
the shaft until the stop pin slips into
position and blocks the shaft.
Mounting the cutting attachment
NGo to "Mounting the Mowing Head"
or "Mounting the Metal Cutting
Attachment".
Mounting the mowing head
Keep the instruction sheet for the
mowing head in a safe place.
STIHL SuperCut 20-2,
STIHL AutoCut 25-2,
STIHL AutoCut C 25-2,
0414BA007 KN
Mounting the Cutting
Attachment
002BA342 KN
2
3
1
002BA346 KN
2
Use a deflector that matches the
cutting attachment – see
"Mounting the Deflector".