FS 311
{
STIHL FS 311
WARNING
Read Instruction Manual thoroughly
before use and follow all safety
precautions – improper use can
cause serious or fatal injury.
ADVERTENCIA
Antes de usar la máquina 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 - 47
Manual de instrucciones
48 - 100
Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2017
0458-433-8621-A. VA3.J17.
0000007421_007_GB
FS 311
English
1
{
This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.
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,
understand and follow the safety
precautions and the operating and
maintenance instructions 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 3
Approved Combinations of Cutting
Attachment, Deflector, Limit Stop
and Harness 17
Mounting the Bike Handle 19
Adjusting the Throttle Cable 20
Mounting the Deflector 20
Mounting the Cutting Attachment 21
Fuel 25
Fueling 26
Fitting the Full Harness 27
Balancing the Machine 27
Starting / Stopping the Engine 28
Transporting the Unit 30
Operating Instructions 31
Replacing the Air Filter 32
Engine Management 32
Adjusting the Carburetor 32
Spark Arresting Screen in Muffler 33
Spark Plug 33
Storing the Machine 34
Sharpening Metal Cutting Blades 34
Maintaining the Mowing Head 35
Maintenance and Care 37
Main Parts 39
Specifications 41
Maintenance and Repairs 42
Disposal 42
Limited Warranty 42
STIHL Incorporated Federal
Emission Control Warranty
Statement 43
STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 45
Trademarks 47
FS 311
English
2
Pictograms
The meanings of the pictograms
attached to or embossed on the
machine are explained in this manual.
Depending on the model concerned, the
following pictograms may be on your
machine.
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:
N A bullet marks a step or procedure.
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration. For example:
N Loosen the screw (1).
N 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 and signal words described
below:
DANGER
Indicates a hazardous situation that, if
not avoided, will result in death or
serious injury.
WARNING
Indicates a hazardous situation that, if
not avoided, could result in death or
serious injury.
NOTICE
Indicates a risk of property damage,
including damage to the machine or its
individual components.
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 differs from those
described in this manual, please contact
your STIHL dealer or the STIHL
distributor for your area for assistance.
Guide to Using this Manual
Fuel tank for gasoline
and engine oil mixture
Press to operate decom
-
pression valve
Manual fuel pump
Press to operate manual
fuel pump
Filler hole for gear
lubricant
Air intake summer mode
Air intake winter mode
Handle heating
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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.
The term "clearing saw" indicates a
high-powered trimmer / brushcutter that
is particularly suited for use with a
circular saw blade to clear saplings or
small trees.
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 deflector, limit
stop and harness 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 clearing saw equipped with the
appropriate cutting attachment only for
cutting grass, brush, wood and similar
material.
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 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
clearing saws. 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 clearing saw involves
1. the operator
2. the power tool
3. the use of the power tool.
Safety Precautions and
Working Techniques
Because a clearing saw
is a high-speed, fast-cut
-
ting 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 311
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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.
– 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.
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.
FS 311
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WARNING
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
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.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts."
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, Limit Stop and
Harness" in the instruction manual or the
STIHL "Cutting Attachments, Parts &
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.
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 Z87 "+" (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.
Wear an approved safety
hard hat to reduce the
risk of injury to your head
when there is a danger of
head injuries.
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 heavy duty
work gloves (e.g. made of
leather or other wear
resistant material) 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.
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended.
FS 311
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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.
WARNING
To reduce the risk of burn
injury, do not touch hot
parts of the machine and
the gear housing when
they are hot.
WARNING
Always shut off the engine and make
sure the cutting attachment has stopped
before putting a clearing saw 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 oil-
gasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual).
WARNING
Fueling Instructions
WARNING
To reduce the risk of serious injury from
burns, never attempt to refuel the unit
until it has been completely removed
from the operator.
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 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.
WARNING
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.
Screw Cap
WARNING
See also the "Fueling" chapter in your
Instruction Manual for additional
information.
234BA016 KN
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 combus
-
tible fuel vapor may
escape from the fuel
system.
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.
Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill quanti
-
ties of fuel. In order to
reduce the risk of fuel
spillage and fire, tighten
the fuel filler cap by hand
as securely as possible.
FS 311
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Before Starting
WARNING
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, 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.
WARNING
Check fuel system for leaks, especially
the visible parts, e.g., filler cap, hose
connections, manual fuel pump (only for
power tools equipped with a manual fuel
pump). Do not start the engine if there
are leaks or damage – risk of fire! Have
the machine repaired by a servicing
dealer before using it.
WARNING
Never operate your power tool if it is
damaged, improperly adjusted or
maintained, or not completely or
securely assembled.
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, fuel mix,
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
As can be seen in that chart, some
cutting attachments may require you to
change your deflector, limit stop 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 Attachment" of your
instruction manual).
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, limit stop
and harness for
the type of cutting
attachment being
used (see chart in
the chapter on
"Approved Combi
-
nations of Cutting
Attachment,
Deflector, Limit
Stop and
Harness").
FS 311
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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
Start the engine at least 10 feet (3 m)
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
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.
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, 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
A
000BA006 KN
B
000BA007 KN
002BA055 KN
FS 311
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9
clearing saw handles and grips are in
good condition and free of moisture,
pitch, oil, fuel mix or grease.
WARNING
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
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.
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
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 by pressing the
stop switch.
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 attach
-
ment. Never touch a
moving cutting attach
-
ment with your hand or
any other part of your
body.
As soon as the engine is
running, this product gen
-
erates toxic exhaust
fumes containing chemi
-
cals, such as unburned
hydrocarbons (including
benzene) and carbon
monoxide, that are
known to cause respira
-
tory problems, 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 inhaling toxic fumes,
never run the machine
indoors or in poorly venti
-
lated locations.
The cutting attachment
continues to rotate for a
short period after the
throttle trigger is released
(flywheel effect.)
FS 311
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WARNING
The rotating cutting attachment may
fling foreign objects directly or by
ricochet a great distance.
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. Even maintaining a
minimum distance of 15 meters cannot
exclude the potential danger. 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
WARNING
This clearing saw is normally to be used
at ground level with the cutting
attachment parallel to the ground. Use of
a clearing saw 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. Never use your clearing saw
as a hedge trimmer.
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 clearing
saw, 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 clearing saw with a loose cutting
attachment.
WARNING
Replace a cracked, damaged or worn-
out head or a cracked, bent, warped,
damaged, dull or worn out blade
immediately, even if damage is limited to
superficial cracks. Such attachments
may shatter at high speed and cause
serious or fatal injury.
WARNING
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 a rotating metal blade strikes a rock or
other hard object, sparks may be
created, which can ignite flammable
materials under certain circumstances.
Flammable materials can include dry
vegetation and brush, particularly when
weather conditions are hot and dry.
When there is a risk of fire or wildfire, do
not use metal blades around flammable
materials or around dry vegetation or
brush. Contact your local fire authorities
or the U.S. Forestry Service if you have
any question about whether vegetation
and weather conditions are suitable for
the use of a metal blade.
Inspect the work area: To
reduce the risk of injury,
remove stones, pieces of
metal and other solid
objects which could be
thrown 15 meters or more
by the cutting attachment
or damage the cutting
attachment and property
(e.g. parked vehicles,
windows).
15m (50ft)
FS 311
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WARNING
If the head, blade or deflector becomes
clogged or stuck, always shut off the
engine and make sure the cutting
attachment has stopped before
cleaning. Grass, weeds, etc. should be
cleaned off the blade or from around the
head at regular intervals.
WARNING
To reduce the risk of unintentional
rotation of the cutting attachment and
injury, always shut off the engine and
remove the spark plug boot before
replacing the cutting attachment. To
reduce the risk of injury, always shut off
the engine before adjusting the length of
the nylon line on manually adjustable
mowing heads.
WARNING
The gearbox becomes hot during
operation. To reduce the risk of burn
injury, do not touch the gear housing
when it is hot.
WARNING
Never modify your muffler. Any
modification could cause an increase in
heat radiation, sparks or sound level,
thereby increasing the risk of fire, burn
injury or hearing loss. You may also
permanently damage the engine. Have
your muffler serviced and repaired by
your STIHL servicing dealer only.
WARNING
The muffler and other parts of the engine
(e.g. fins of the cylinder, spark plug)
become hot during operation and remain
hot for a while after stopping the engine.
To reduce risk of burns, do not touch the
muffler and other parts while they are
hot. Keep the area around the muffler
clean. Remove excess lubricant and all
debris such as pine needles, branches
or leaves. Let the engine cool down
sitting on concrete, metal, bare ground
or solid wood (away from any
combustible substances.
WARNING
An improperly mounted or damaged
cylinder housing or a
damaged/deformed muffler shell may
interfere with the cooling process of the
muffler. To reduce the risk of fire or burn
injury, do not continue work with a
damaged or improperly mounted
cylinder housing or a
damaged/deformed muffler shell.
Your muffler is furnished with a spark
arresting screen designed to reduce the
risk of fire from the emission of hot
particles. Never operate your unit with a
missing or damaged spark arresting
screen. If your gas/oil mix ratio is correct
(i.e., not too rich), this screen will
normally stay clean as a result of the
heat from the muffler and need no
service or maintenance. If you
experience loss of performance and you
suspect a clogged screen, have your
muffler maintained by a STIHL servicing
dealer. Some state or federal laws or
regulations may require a properly
maintained spark arrestor for certain
uses. See the "Maintenance, Repair and
Storing" section of these Safety
Precautions. Remember that the risk of
a brush or forest fire is greater in hot or
dry conditions.
WARNING
USING THE CUTTING ATTACHMENT
For an illustration of the various cutting
attachments and instructions on proper
mounting see the chapter on "Mounting
the Cutting Attachment" in your
instruction manual.
Some STIHL power tools
are equipped with a cata
-
lytic converter, which is
designed to reduce the
exhaust emissions of the
engine by a chemical pro
-
cess in the muffler. Due
to this process, the muf
-
fler does not cool down
as rapidly as conven
-
tional mufflers when the
engine returns to idle or
is shut off. To reduce the
risk of fire and burn inju
-
ries when using a
catalytic converter,
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 com
-
bustible materials while it
is still hot.
FS 311
English
12
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 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
clearing saws equipped with a line-
limiting blade in the deflector in order to
keep the line at the proper length (see
"Main Parts" 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.
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 AutoCut mowing head
Nylon cutting line advances
automatically when tapped against the
ground (TapAction).
STIHL TrimCut mowing head
Frayed line is replaced by a simple
adjustment (see instruction sheet
supplied with mowing head).
STIHL DuroCut mowing head
Uses only nylon lines.
Observe wear indicators.
NOTICE
There are four wear limit indicators
shaped like exclamation marks in the
base of the DuroCut. If one of these
built-in indicators becomes visible, do
not continue using the DuroCut since it
might otherwise be damaged. Replace
the worn base plate with a new base
plate. It is important to follow the
maintenance instructions supplied with
the head.
STIHL PolyCut mowing head
Uses either nylon lines or nonrigid,
pivoting polymer blades.
Observe wear indicators.
002BA354 KN
681BA209 KN
002BA177 KN
FS 311
English
13
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.
WARNING
If the wear limit marks are ignored, there
is a risk of the cutting attachment
shattering 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.
Risk of Kickout (Blade Thrust) with all
Rigid Cutting Blades
WARNING
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.
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.
Using the Brush Knife
When fitted to the power tool, the brush
knife is suitable for applications ranging
from cutting matted grass to clearing
weeds, wild growth and scrub.
Kickout (blade thrust) is
the sudden and uncon
-
trolled motion towards
the operator's right or
rear that can occur when
the shaded area (espe
-
cially 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 counterclock
-
wise 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
002BA355 KN
FS 311
English
14
To cut wild growth and scrub, lower the
rotating brush knife down onto the
growth to achieve a chopping effect –
but keep the tool below waist height at
all times.
WARNING
Exercise extreme caution when using
this method of cutting. The higher the
cutting attachment is off the ground, the
greater the risk of loss of control and of
cuttings being thrown sideways.
Use the power tool like a scythe to cut
grass, i.e. sweep it to and fro in an arc.
WARNING
When cutting woody materials, use the
left side of the blade to avoid "kickout"
(blade thrust) situations.
WARNING
Improper use of a brush knife may cause
it to crack, chip or shatter. Thrown blade
fragments may seriously or fatally injure
the operator or bystanders. To reduce
the risk of injury, avoid contact with hard
or solid foreign objects such as stones,
rocks or pieces of metal.
WARNING
When cutting young saplings or other
woody materials up to 2 cm (3/4 in.) in
diameter, use the left side of the blade to
avoid "kickout" situations (see section
on "Risk of kickout (blade thrust) with all
rigid cutting blades"). Do not attempt to
cut woody material with a larger
diameter, since the blade may catch or
jerk the power tool forward. This may
cause damage to the blade or power tool
or loss of control of the power tool,
resulting in personal injury. Use a
circular saw blade for such work.
WARNING
Inspect the brush knife at regular short
intervals for signs of damage. Do not
continue working with a damaged brush
knife. Resharpen the brush knife
regularly (when it has dulled noticeably).
Using the Circular Saw Blade
Circular saw blades are suitable for
thinning brush and cutting small trees up
to a diameter of 7 cm (2 3/4 in.). Do not
attempt to cut trees with larger
diameters, since the blade may catch or
jerk the clearing saw forward. This may
cause damage to the blade or loss of
control of the power tool and result in
serious injury. Use a chain saw for such
work.
WARNING
To reduce the risk that the blade will
crack and / or break, avoid all contact
with stones, rocks or the ground.
Sharpen blades in a timely manner as
specified – dull teeth may cause the
blade to crack or shatter.
When a clearing saw with a circular saw
blade is used to cut down small trees,
STIHL recommends that the standard
deflector be removed and replaced by
the special limit stop deflector (see
chapter on "Mounting the Deflector").
This limit stop helps to keep the unit
positioned against the tree during the
cutting process. Inexperienced users
should place the left side of the stop
against the tree trunk before beginning
to cut. This will keep the clearing saw
against the tree during the cutting
operation and will reduce the risk of loss
of control and possible kickout
(described above and briefly again
below).
Before starting the cut, accelerate the
engine up to full throttle. Perform cut
with uniform pressure. STIHL
recommends that the circular saw blade
002BA509 KN
002BA067 KN
002BA214 ST
FS 311
English
15
be applied to the right of the tree, using
the non-shaded area of the blade, as
shown in the illustration above.
WARNING
The risk of kickout is highest when
cutting in the darker shaded area. To
reduce the risk of kickout and resulting
injury, do not use this area of the circular
saw blade for cutting trees or shrubs.
Special techniques using the lighter
shaded areas of the blade to cut shrubs
and trees should only be used by
experienced operators with specialized
training in the use and control of the
clearing saw.
When felling small trees, maintain a
distance of at least two tree lengths from
the nearest coworker.
WARNING
In order to reduce the risk of injury from
thrown objects or operator contact with
the blade or head, be sure to remount
the standard deflector when no longer
using a circular saw blade.
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 the spark plug boot snugly onto
the spark plug terminal of the proper
size. (Note: If the terminal has a
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.
Your muffler is equipped with a spark-
arresting screen to reduce the risk of
fire; never operate your power tool if the
screen is missing, damaged or clogged.
Remember that the risk of a brush or
forest fire is greater in hot or dry
weather.
In California, it is a violation of § 4442 or
§ 4443 of the Public Resources Code to
use or operate gasoline-powered tools
on forest-covered, brush-covered or
grass-covered land unless the engine’s
exhaust system is equipped with a
complying spark arrester that is
maintained in effective working order.
The owner/operator of this product is
responsible for properly maintaining the
spark arrester. Other states or
governmental entities/agencies, such as
the U.S. Forest Service, may have
similar requirements. Contact your local
002BA068 KN
FS 311
English
16
fire agency or forest service for the laws
or regulations relating to fire protection
requirements.
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.
Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.
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 311
English
17
Approved Combinations of Cutting Attachment, Deflector, Limit Stop and Harness
Cutting Attachment Deflector, Limit Stop Harness
1
6
7
8
910 14
11
12
2
4
5
16
17
3
13
15
0000-GXX-1676-A0
FS 311
English
18
Approved Combinations
Select correct combination from the
table according to the cutting
attachment you intend to use.
WARNING
For safety reasons only the cutting
attachments and deflectors or limit stops
shown in each row of the table may be
used together. No other combinations
are permitted – risk of accidents.
Cutting Attachments
Mowing heads
1 STIHL SuperCut 40-2
2 STIHL AutoCut 40-2
3 STIHL AutoCut 46-2
4 STIHL TrimCut 40-2
5 STIHL TrimCut 41-2
6 STIHL DuroCut 40-4
7 STIHL PolyCut 40-3
Metal cutting attachments
8 Grass cutting blade 230-4
(230 mm dia.)
9 Grass cutting blade 255-8
(255 mm dia.)
10 Brush knife 300-3
(300 mm dia.)
11 Scratcher tooth circular saw blade
200
(200 mm dia.)
12 Chisel tooth circular saw blade 200-
22 (4119), chisel tooth circular saw
blade 200-22 HP (4000)
WARNING
Non-metal grass cutting blades, brush
knives and circular saw blades are not
approved.
Deflectors, Limit Stop
13 Deflector for mowing heads
14 Deflector for grass cutting blades
and brush knives
15 Limit stop for circular saw blades
Harness
16 Full harness must be used
17 Full "deluxe" harness must be used
WARNING
Based on the cutting attachment being
used:
Choose the proper deflector in order to
reduce the risk of serious personal 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 serious personal injury
from loss of control and contact with the
cutting attachment.
To reduce the risk of serious personal
injury from contact with the cutting
attachment, use grass cutting metal
blades and brush knives on this unit only
if equipped with a bike handle or a loop
handle with barrier bar. Use circular saw
blades on this unit only if equipped with
a bike handle.
Do not use rigid plastic blades on this
unit.
FS 311
English
19
N Hold the lower clamp (1) and upper
clamp (2) firmly together.
N Release the clamp screw (3) – the
clamps are loose once the clamp
screw has been released. They are
pushed apart by the two
springs (4 and 5).
N Pull out the clamp screw – the
washer (6) remains on the clamp
screw.
N Separate the clamp moldings – the
springs (4 and 5) remain in the
lower clamp.
N Place the handlebar (4) in the lower
clamp (1) so that distance A is no
more than 15 cm (6 in).
N Place the upper clamp (2) in
position and press it down.
N Insert the clamp screw (3).
N Line up the handlebar (4) at a right
angle to the drive tube.
N Tighten down the clamp screw (3)
firmly.
N Take out the screw (5), the nut (6)
remains in the control handle (7).
N Push the control handle onto the
handlebar (4) until the holes (9) line
up – the throttle trigger (8) must
point towards the gearbox.
N Insert the screw and tighten it down
firmly.
N Go to "Adjusting the Throttle Cable".
Transport and storage position: Loosen
the clamp screw, turn the handlebar in
line with the drive tube and fold the
handles down.
Mounting the Bike Handle
0000-GXX-2034-A0
A
4
1
0000-GXX-0524-A0
9
5
7
8
4
9
0000-GXX-0525-A0
6
7
FS 311
English
20
It may be necessary to correct the
adjustment of the throttle cable after
assembling the machine or after a
prolonged period of operation.
Adjust the throttle cable only when the
unit is completely and properly
assembled.
N Set the throttle trigger to the full
throttle position.
N Carefully rotate the screw in the
throttle trigger in the direction of the
arrow until you feel initial resistance.
Then rotate it another half turn in the
same direction.
Use the Right Deflector
WARNING
Deflector (1) is approved for mowing
heads only and must therefore be
mounted before fitting a mowing head.
WARNING
Deflector (2) is approved for grass
cutting blades and brush knives only and
must therefore be mounted before fitting
a grass cutting blade or brush knife.
WARNING
The limit stop (3) is approved as a
deflector for circular saw blades only
and must therefore be mounted before
fitting a circular saw blade. It is also
necessary to change the guard ring (5),
see "Mounting the Cutting Attachment" /
"Mounting Circular Saw Blades".
Mounting the Deflector
Deflectors (1 to 3) are mounted to the
gearbox in the same way.
N Remove dirt from joints on gearbox
and defelector – make sure that no
dirt gets into the screw holes in the
gearbox.
N Place the deflector on the gearbox
(5).
N Insert the screws (6) and tighten
them down firmly.
Adjusting the Throttle Cable
002BA655 KN
Mounting the Deflector
1
002BA401 KN
2
002BA402 KN
3
002BA433 KN
4
6
5
002BA434 KN
FS 311
English
21
Placing power tool on the ground
N Shut off the engine.
N Lay your power tool on its back so
that the cutting attachment
mounting face is pointing up.
Use the Right Guard Ring
Your power tool comes standard with a
guard ring.
The guard ring is also available as a
special accessory.
The guard ring must be mounted with
particular care. Have this work
performed by your servicing dealer.
STIHL recommends a STIHL servicing
dealer.
Guard ring for mowing applications
Always fit guard ring (1) when using
– mowing heads
– grass cutting blades
– brush knives
– shredder blades
to ensure optimum protection against
grass cuttings.
Guard ring for sawing applications
Fit guard ring (4) only when you use
circular saw blades.
Mounting the Thrust Plate and Guard
Washer
N Fit the thrust plate (1) and guard
washer (2) on the shaft (3).
NOTICE
The thrust plate (1) on the gearbox is
necessary for mounting all cutting
attachments.
NOTICE
The guard washer (2) is required for
mounting
– mowing heads
– grass cutting blades
– brush knives
– shredder blades
to the gearbox. The guard washer is not
required for mounting circular saw
blades.
Mounting the Cutting
Attachment
002BA406 KN
002BA490 KN
2
1
3
5
002BA491 KN
4
2
002BA407 KN
1
2
3
4
FS 311
English
22
Checking the Thrust Plate
The thrust plate consists of the thrust
plate body (1) to which a captive guard
washer (2) is fitted.
WARNING
Never use a thrust plate without the
guard washer. Always replace a thrust
plate if the guard washer is missing.
Cleaning Gearbox Mounting Hardware
for Cutting Attachment
NOTICE
Check inside of guard ring (4) and area
around it for dirt at regular intervals, or
when you change the cutting
attachment, and clean if necessary as
follows:
N Pull the guard washer (1) and thrust
plate (2) off the shaft.
N Thoroughly clean the guard ring,
shaft, thrust plate and guard washer
– do not remove the guard ring.
Blocking the Shaft
The output shaft (1) must be blocked
with the stop pin (2) to mount or remove
cutting attachments. The stop pin is
included with the machine and is
available as a special accessory.
N Insert the stop pin (2) in the bore (3)
in the gearbox as far as stop, apply
slight pressure.
N Rotate shaft or cutting attachment
until the stop pin slips into position
and blocks the shaft.
Mounting the Cutting Attachment
WARNING
Use a deflector that matches the cutting
attachment – see "Mounting the
Deflector".
Fitting Mowing Head with Screw
Mounting
Keep the instruction leaflet for the
mowing head in a safe place.
N Screw the mowing head
counterclockwise on to the shaft (1)
as far as stop.
N Block the shaft.
N Tighten down the mowing head
firmly.
NOTICE
Remove the tool used to block the shaft.
Removing the Mowing Head
N Block the shaft.
N Unscrew the mowing head
clockwise.
1
2
1
681BA196 KN
2
002BA407 KN
1
2
3
4
2
3
1
0812BA021 KN
2
1
002BA385 KN
FS 311
English
23
Removing and Installing Metal Cutting
Attachments
Keep the leaflet and packaging of the
metal cutting attachment in a safe place.
WARNING
Wear protective gloves to reduce the
risk of direct contact with the sharp
cutting edges.
Mount only one metal cutting
attachment.
Mounting Grass Cutting Blades, Brush
Knife
Notice on new machines that come
standard with a mowing head only: A
"metal mowing attachment mounting kit"
is required to mount a grass cutting
blade or brush knife. Kits are available
from your servicing dealer.
Check direction of rotation of cutting
attachment
The cutting edges of the cutting
attachments 1 and 2 must point
clockwise.
Cutting attachments 3 and 4 may be
mounted either way round – they must
be turned over regularly to help avoid
one-sided wear.
N Use guard ring for mowing
attachments.
N Place the cutting attachment (1) in
position.
WARNING
Collar (a) must locate in the cutting
attachment's mounting hole (b).
Securing the cutting attachment
N Fit the thrust washer (2) – convex
side must face up.
N Fit the rider plate (3).
N Block the shaft.
N Fit the nut (4) counterclockwise and
tighten it down firmly.
WARNING
If the mounting nut has become too
loose, fit a new one.
NOTICE
Remove the tool used to block the shaft.
0000-GXX-0421-A0
1 2
3
4
2
3
1
4
002BA409 KN
b
a
FS 311
English
24
Removing the cutting attachment
N Block the shaft.
N Unscrew the nut clockwise.
N Pull the cutting attachment with its
mounting hardware off the gearbox.
Mounting Circular Saw Blades
A limit stop kit, which includes a limit
stop and a guard ring for circular saw
blades, is available as a special
accessory for mounting circular saw
blades.
Notice on new machines that come
standard with a mowing head only:
Further mounting hardware is necessary
for a circular saw blade. It is available
from your servicing dealer.
Change the guard ring.
Recommendation: The guard ring must
be mounted with particular care. Have
this work performed by your servicing
dealer. STIHL recommends a STIHL
servicing dealer.
N Remove the guard washer (1) and
thrust plate (2).
N Remove the guard ring (3) for
mowing attachments.
N Keep the guard washer and guard
ring in a safe place for future use.
N Fit the guard ring (4) for saw blades.
N Slip the thrust plate (2) over the
shaft.
N Fit the limit stop (5) for circular saw
blades.
NOTICE
Do not use the guard washer (1) with
circular saw blades.
Check direction of rotation of cutting
attachment
Cutting edges of circular saw blades
must point clockwise.
N Place the cutting attachment (1) in
position.
WARNING
Collar (a) must locate in the cutting
attachment's mounting hole (b).
Securing the cutting attachment
N Fit the thrust washer (2) – convex
side must face up.
N Fit the rider plate (3).
A rider plate (3) for sawing applications
is available as a special accessory. It
allows the full depth of cut of the saw
blade to be used.
N Block the shaft.
N Fit the nut (4) counterclockwise and
tighten it down firmly.
002BA490 KN
2
1
3
5
002BA491 KN
4
2
681BA165 KN
2
3
1
4
002BA423 KN
b
a
FS 311
English
25
WARNING
If the mounting nut has become too
loose, fit a new one.
NOTICE
Remove the tool used to block the shaft.
Removing the cutting attachment
N Block the shaft.
N Unscrew the mounting nut
clockwise.
N Pull the cutting attachment with its
mounting hardware off the gearbox.
This engine is certified to operate on
unleaded gasoline and the STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of high-
quality gasoline and two-stroke air
cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 ((R+M)/2)
and no more than 10% ethanol content.
Fuel with an octane rating below 89 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 damage the
engine. For this reason STIHL
recommends that you use only quality
unleaded gasoline!
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
and should not be used.
For further details, see
www.STIHLusa.com/ethanol
The ethanol content in gasoline affects
engine speed – it may be necessary to
readjust the carburetor if you use fuels
with various ethanol contents.
WARNING
To reduce the risk of personal injury
from loss of control and / or contact with
the running cutting tool, do not use your
unit with incorrect idle adjustment. At
correct idle speed, the cutting tool
should not move.
If your power tool´s idle speed is
incorrectly adjusted, have your
authorized STIHL servicing dealer
check your machine and make the
proper adjustments and repairs.
The idle speed and maximum speed of
the engine change if you switch from a
fuel with a certain ethanol content to
another fuel with a much higher or lower
ethanol content.
This problem can be avoided by always
using fuel with the same ethanol
content.
To ensure the maximum performance of
your STIHL engine, use a high quality 2-
cycle engine oil, such as STIHL 2-cycle
engine oils. STIHL 2-cycle engine oils
are specially designed for STIHL
engines. To help your engine run
cleaner and reduce harmful carbon
deposits, STIHL recommends using
STIHL HP Ultra 2-cycle engine oil, or
use an equivalent high quality 2-cycle
engine oil.
To meet the requirements of EPA and
CARB we recommend to use STIHL HP
Ultra oil or equivalent.
Do not use BIA or TCW rated (two-
stroke 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,
chain saws, mopeds, etc.).
Fuel
FS 311
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26
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the container
from your vehicle and place the
container on the ground before filling. To
reduce the risk of sparks from static
discharge and resulting fire and/or
explosion, do not fill fuel containers that
are sitting in or on a vehicle or trailer.
The container should be kept tightly
closed in order to limit the amount of
moisture that gets into the mixture.
The machine’s fuel tank should be
cleaned as necessary.
STIHL MotoMix
STIHL recommends the use of STIHL
MotoMix. STIHL MotoMix has a high
octane rating and ensures that you
always use the right gasoline/oil mix
ratio.
STIHL MotoMix uses STIHL HP Ultra
two-stroke engine oil suited for high
performance engines.
For further details, see
www.STIHLusa.com/ethanol
Fuel mix ages
If not using STIHL MotoMix, only mix
sufficient fuel for a few days of work, not
to exceed 30 days of storage. Store in
approved fuel-containers only. When
mixing, pour oil into the container first,
and then add gasoline. Close the
container and shake it vigorously by
hand to ensure proper mix of oil and
gasoline.
Dispose of empty mixing-oil containers
only at authorized disposal locations.
Preparations
N 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.
N Position the machine so that the
filler cap is facing up.
WARNING
To reduce the risk of fire and personal
injuries due to escaping fuel and vapor,
remove the fuel filler cap carefully so
that any excess pressure in the tank can
escape slowly.
Use the proper seasonal gasoline blend,
i.e., winter blend in winter, summer
blend in summer.
Gasoline Oil (STIHL 50:1 or equiva
-
lent high-quality oils)
Liters Liters (ml)
10.02(20)
5 0.10 (100)
10 0.20 (200)
20 0.40 (400)
US gal. US fl.oz.
12.6
2 1/2 6.4
512.8
Fueling
0000-GXX-0476-A0
FS 311
English
27
Opening the threaded filler cap
N Turn the cap counterclockwise until
it can be removed from the tank
opening.
N Remove the filler cap.
Refueling
Take care not to spill fuel while fueling
and do not overfill the tank.
Closing the threaded filler cap
N Position cap.
N Turn the cap clockwise as far as it
will go and tighten it as securely as
possible by hand.
N Put on the full harness (1).
N Adjust the length of the strap so that
the spring hook (2) is about a hand’s
width below your right hip. Over-
long ends of straps may be
shortened after completing the
adjustment.
N Attach the spring hook to the
machine's perforated strip (3).
Find the right attachment point for the
cutting attachment you are using – see
"Balancing the Brushcutter".
The unit is balanced differently,
depending on the cutting attachment
used.
N With the unit suspended from the
harness, see how it is balanced and
change attachment point as
necessary:
Mowing attachments
Mowing heads, grass cutting blades and
brush knives should just touch the
ground.
Circular saw blades
Circular saw blades should "hover"
about 8 in. (20 cm) above the ground.
002BA447 KN
002BA448 KN
Fitting the Full Harness
2
3
1
002BA240 KN
Balancing the Machine
256BA016 KN
256BA017 KN
FS 311
English
28
Controls
1 Throttle trigger lockout
2 Throttle trigger
3 Stop switch with Run and Stop
positions. Depress the stop switch
(…) to switch off the ignition – see
"Function of stop switch and ignition
system".
Function of stop switch and ignition
system
The ignition is switched off and the
engine stopped when the stop switch is
pressed. The stop switch returns
automatically to the Run position when it
is released: The ignition is switched on
again after the engine stops – the engine
is then ready to start.
Starting the Engine
N Press the manual fuel pump
bulb (9) at least five times – even if
the bulb is already filled with fuel.
N Press in the choke knob (8) and turn
it to the position that suits the engine
temperature:
The choke knob must engage in
position.
Cranking
N Place the unit on the ground: It must
rest securely on the engine support
and the deflector.
N If fitted: Remove the transport guard
from the cutting attachment.
To reduce the risk of accidents, check
that the cutting attachment is not
touching the ground of any other
obstacles.
N Make sure you have a firm footing,
either standing, stooping or
kneeling.
N Hold the unit firmly on the ground
with your left hand and press down
– do not touch the throttle trigger or
lockout lever – your thumb should
be under the fan housing.
NOTICE
Do not stand or kneel on the drive tube.
Starting / Stopping the
Engine
3
1
2
0000-GXX-0494-A0
g if the engine is cold
< for warm start – also use this posi
-
tion if the engine has been running
but is still cold.
0000-GXX-0478-A0
0000-GXX-0526-A0
0000-GXX-0527-A0
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