STIHL HS 81 R, HS 81, HS 81 T Instruction Manual
STIHL HS 81
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 - 33
Manual de
instrucciones
35 - 70
Contents
English
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 3
Using the Unit 11
Fuel 12
Fueling 13
Rear Handle 15
Starting / Stopping the Engine 15
Original Instruction ManualPrinted on chlorine-free paper
Cleaning the Air Filter 16
Engine Management 17
Adjusting the Carburetor 18
Spark Arresting Screen in Muffler 19
Checking the Spark Plug 19
Lubricating the Gearbox 20
Rewind Starter 21
Storing the Machine 21
Sharpening Instructions 22
Inspections and Maintenance by
Dealer 22
Maintenance and Care 23
Main Parts 25
Specifications 27
Printing inks contain vegetable oils, paper can be recycled.
Special Accessories 28
Maintenance and Repairs 28
STIHL Incorporated Federal
Emission Control Warranty
Statement 28
STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 30
Trademarks 32
Allow only persons who fully understand
this manual to operate your hedge
trimmer.
To receive maximum performance and
satisfaction from your STIHL hedge
trimmer, 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 hedge
trimmer. 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 hedge trimmer is a highspeed cutting tool some special safety
precautions must be observed to reduce
the risk of personal injury. Careless or
improper use may cause serious or
even fatal injury.
{
© ANDREAS STIHL AG & Co. KG, 2011
0458-442-8621-B. M2-6.G11.PM.
0000000779_005_GB
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
1
English
Guide to Using this Manual
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.
Fuel tank for gasoline
and engine oil mixture
Press to operate manual
fuel pump
Filler hole for gear
lubricant
Starting lock
Rotating rear handle
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration. 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 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.
your machine differs from those
described in this manual, please contact
your STIHL dealer for assistance.
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.
2
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
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
Safety Precautions and
Working Techniques
Because a hedge trimmer is a high-speed, fastcutting power tool with
sharp cutting blades,
special safety precautions must be observed to
reduce the risk of personal injury.
It is important that you
read, fully understand
and observe the following
safety precautions and
warnings. Read the
instruction manual and
the safety precautions
periodically. Careless or
improper use may cause
serious or fatal injury.
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 cutting tool comes in contact
with your body, it will cut you.
Use your hedge trimmer only for cutting
hedges, shrubs, scrub, bushes 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
hedge trimmers. 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 hedge trimmer involves
1. the operator
2. the power tool
3. the use of the power tool.
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.
Warning!
Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition
that might be aggravated by strenuous
work, check with your doctor before
operating this machine.
Warning!
Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
These conditions reduce the hand's
ability to feel and regulate temperature,
produce numbness and burning
sensations and may cause nerve and
circulation damage and tissue necrosis.
All factors which contribute to
whitefinger disease are not known, but
cold weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
3
English
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
Warning!
To reduce the risk of injury, the operator
should wear proper protective apparel.
Warning!
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 standard.) To
reduce the risk of injury to your face
STIHL recommends that you also wear
a face shield or face screen over your
goggles or protective glasses.
Power tool noise may damage your
hearing. Wear sound barriers (ear plugs
or ear mufflers) to protect your hearing.
Continual and regular users should
have their hearing checked regularly.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
Always wear gloves
when handling the
machine and the cutting
tool. 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.
Avoid loose-fitting jackets, scarfs,
neckties, jewelry, flared or cuffed pants,
unconfined long hair or anything that
could become caught on branches,
brush or the moving parts of the unit.
Secure hair so it is above shoulder level.
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts".
4
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
Warning!
Never modify this power tool in any way.
Only attachments supplied by STIHL or
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.
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 blade
contact, never carry or transport your
power tool with the cutter blades
moving.
It may be carried only in the horizontal
position. Grip the front handle and keep
the hot muffler away from your body and
the cutter blades behind you.
Warning!
Always switch off the engine and fit the
scabbard over the cutter blades before
transporting the power tool over long
distances. When transporting it in a
vehicle, properly secure it to prevent
turnover, fuel spillage and damage to
the unit.
Fuel
Your STIHL power tool uses an oilgasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual.)
Warning!
Gasoline is an extremely
flammable fuel. If spilled
and ignited by a spark or
other ignition source, it
can cause fire and 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.
Fueling Instructions
Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before refueling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
In order to reduce the risk of burns and
other personal injury from escaping gas
vapor 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.
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
5
English
001BA220 KN
001BA227 KN
001BA226 KN
Warning!
Check for fuel leakage
while refueling and during operation. If fuel
leakage is found, do not
start or run the engine
until the leak is fixed and
any spilled fuel has been wiped away.
Take care not to get fuel on your clothing. If this happens, change your
clothing immediately.
Different models may be equipped with
different fuel caps.
Toolless cap with grip
Warning!
In order to reduce the risk of fuel spillage and fire from an improperly
tightened fuel cap, correctly position
and tighten the fuel cap in the fuel tank
opening.
To do this with this STIHL cap, raise the
grip on the top of the cap until it is upright
at a 90° angle. Insert the cap in the fuel
tank opening with the raised positioning
marks on the grip of the cap and on the
fuel tank opening lining up. Using the
grip, press the cap down firmly while
turning it clockwise as far as it will go
(approx. 1/4 turn).
Fold the grip flush with
the top of the cap. Grip
the cap and check for
tightness. If the grip does
not lie completely flush
with the cap and the
detent on the grip does
not fit in the corresponding recess in the filler
opening, or if the cap is
loose in the filler opening,
the cap is not properly
seated and tightened and
you must repeat the
above steps.
Misaligned, damaged or broken cap
N If the cap does not drop fully into the
opening when the positioning marks
line up and/or if the cap does not
tighten properly when twisted, the
base of the cap may be prematurely
rotated (in relation to the top) to the
closed position. Such misalignment
can result from handling, cleaning
or an improper attempt at
tightening.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
N To return the cap to the open
position for installation, turn the cap
(with the grip up) until it drops fully
into the tank opening. Next, twist the
cap counterclockwise as far as it will
go (approx. 1/4 turn) – this will twist
the base of the cap into the correct
position. Then, twist the cap
clockwise, closing it normally.
N If your cap still does not tighten
properly, it may be damaged or
broken; immediately stop use of the
unit and take it to your authorized
STIHL dealer for repair.
Screw Cap
Warning!
Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill quantities of fuel. In order to
reduce the risk of fuel
spillage and fire, tighten the fuel filler
cap by hand as securely as possible.
See also the "Fueling" chapter in your
Instruction Manual for additional
information.
6
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
Before Starting
Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, stop switch and cutting
tool. The throttle trigger (if applicable)
must move freely and always spring
back to the idle position. Never attempt
to modify the controls or safety devices.
Warning!
Never use a power tool that is damaged
or not properly maintained.
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.
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!
The cutting tool must be properly tightened and in safe operating condition.
Inspect for loose parts (nuts, screws,
etc.) and for cracked, bent, warped or
damaged blades. Regularly check the
condition and tightness of the cutter
blades – with the engine stopped!
Replace damaged cutter blades before
using the power tool. Always keep
blades sharp.
STIHL recommends that you always
spray the cutter blades with STIHL resin
solvent before starting work – with the
engine stopped! You can obtain this
protective spray from your dealer. Apply
generously.
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
contact, be absolutely sure that the cutting tool 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 blades on the cutting tool.
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.
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 tool, do not use your unit
with incorrect idle adjustment. At correct
idle speed, the cutting tool should not
move. For directions on how to adjust
idle speed, see the appropriate section
of your instruction manual.
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
7
English
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.
Right-hand Use
Put your right hand on the rear handle,
left hand on the front handle.
Operate the machine so that the cutting
blades are always away from your body.
Left-hand Use
Put your left hand on the rear handle,
right hand on the front handle.
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 tool. Never touch
a moving cutting tool 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, overgrown terrain. Watch for hidden
obstacles such as tree stumps, roots
and ditches to avoid stumbling. For better footing, clear away fallen branches,
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, in a tree
or any other insecure support. Never
hold the machine above shoulder
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!
As soon as the engine is
running, this product generates toxic exhaust
fumes containing chemicals, such as unburned
hydrocarbons (including
benzene) and carbon monoxide, that
are known to cause respiratory problems, cancer, birth defects, or other
reproductive harm. Some of the gases
(e.g. carbon monoxide) may be colorless and odorless. To reduce the risk of
serious or fatal injury / illness from inhaling toxic fumes, never run the machine
indoors or in poorly ventilated locations.
Warning!
If the vegetation being cut or the surrounding ground is coated with a
chemical substance (such as an active
pesticide or herbicide), read and follow
the instructions and warnings that
accompanied the substance at issue.
8
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
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, switch off
the engine immediately – move the slide
control / stop switch to 0 or STOP.
Warning!
The cutter blades continue to move for a
short period after the throttle trigger is
released (flywheel effect.)
Accelerating the engine while the blades
are blocked increases the load and will
cause the clutch to slip continuously.
This may result in overheating and
damage to important components (e.g.
clutch, polymer housing components) –
which can then increase the risk of injury
from the blades moving while the engine
is idling.
Warning!
Before you start work, examine the
hedge area for stones, fence wire, metal
or other solid objects which could damage the cutter blades.
Take particular care when cutting
hedges next to or against wire fences.
Do not touch the wire with the cutting
blades. When working close to the
ground, make sure that no sand, grit or
stones get between the cutter blades.
Striking solid foreign objects such as
stones, fence wire or metal could
damage the cutting attachment and may
cause blades to crack, chip or break.
STIHL does not recommend the use of
your power tool when cutting in areas
where the blades could contact such
objects.
Warning!
Observe the cutting blades at all times –
do not cut any areas of the hedge that
you cannot see. When cutting the top of
a taller hedge, check the other side of
the hedge frequently for bystanders,
animals and obstructions.
English
Danger!
Your power tool is not
insulated against electric
shock. To reduce the risk
of electrocution, never
operate this power tool in
the vicinity of any wires or
cables (power, etc.) which may be carrying electric current.
Warning!
If the cutting tool becomes clogged or
stuck, always turn off the engine and
make sure the cutting tool has stopped
before cleaning. Grass, weeds, etc.
should be cleaned off the cutting tool at
regular intervals.
Check the cutting blades at regular short
intervals during operation, or
immediately if there is a noticeable
change in cutting behavior:
– Shut off the engine.
– Wait until the cutting blades have
come to a complete standstill.
– Check condition and tightness, look
for cracks.
– Check sharpness.
– Replace damaged or dull cutting
tools immediately, even if they have
only superficial cracks.
Warning!
The gearbox becomes hot during operation. To reduce the risk of burn injury,
do not touch the gear housing when it is
hot.
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
9
English
Warning!
The muffler and other parts of the
engine (e.g. fins of the cylinder, spark
plug) become hot during operation and
remain hot for a while after stopping the
engine. To reduce risk of burns do not
touch the muffler and other parts while
they are hot.
Warning!
To reduce the risk of fire and burn injury,
keep the area around the muffler clean.
Remove excess lubricant and all debris
such as pine needles, branches or
leaves. Let the engine cool down sitting
on concrete, metal, bare ground or solid
wood (e.g. the trunk of a felled tree)
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.
After Finishing Work
Always clean dust and dirt off the
machine – do not use any grease
solvents for this purpose.
Spray the blades with STIHL resin
solvent. Start and run the engine briefly
so that the solvent is evenly distributed.
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
section of your instruction manual.
Please refer to the maintenance chart in
this manual.
Warning!
Always stop the engine and make sure
that the cutting tool is stopped before
doing any maintenance or repair work or
cleaning the power tool. Do not attempt
any maintenance or repair work not
described in your instruction manual.
Have such work performed by your
STIHL servicing dealer only.
Wear gloves when handling or
performing maintenance on blades.
Warning!
Use the specified spark plug and make
sure it and the ignition lead are always
clean and in good condition. Always
press spark plug boot snugly onto spark
plug terminal of the proper size. (Note: If
terminal has detachable SAE adapter
nut, it must be securely attached.) A
loose connection between spark plug
terminal 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
ignition wire boot removed from the
spark plug or with a removed spark
plug, since uncontained sparking may
cause a fire.
Warning!
Do not operate your power tool if the
muffler is damaged, missing or modified. An improperly maintained muffler
will increase the risk of fire and hearing
loss. If your muffler was equipped with a
spark-arresting screen to reduce the
risk of fire, never operate your power
tool if the screen is missing or damaged.
Remember that the risk of forest fires is
greater in hot or dry weather.
Warning!
Never repair damaged cutting attachments by welding, straightening or modifying the shape. This may cause parts
of the cutting tool to come off and result
in serious or fatal injuries.
10
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
Keep the cutting tool 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 this
manual.
Using the Unit
HS 81 R
The HS 81 R is designed for cutting
hedges and shrubs with thicker stems
and branches.
HS 81 T
Do not use your power tool during other
people's rest periods.
Cutting Sequence
Use lopping shears or a chain saw to cut
out thick branches first.
Cut both sides of the hedge first, then
the top.
Disposal
Do not throw cuttings in the garbage can
– they can be composted!
HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
The HS 81 T is designed for shaping
and trimming hedges and shrubs with
thinner branches.
Use the HS 81 R hedge trimmer for
cutting hedges with thicker branches.
Cutting Season
Observe country-specific or municipal
rules and regulations for cutting hedges.
11
English
Working Technique
Vertical Cut
Swing the cutting blade from the bottom
upwards in an arc – lower the nose of the
blade, move along the hedge and then
swing the blade up again in an arc.
Any working position above head height
is tiring. To minimize the risk of
accidents, work in such positions for
short periods only.
Horizontal Cut
Hold the cutter bar at an angle of 0° to
10° as you swing the hedge trimmer
horizontally.
Swing the cutting blade in an arc
towards the outside of the hedge so that
the cuttings are swept to the ground.
Fuel
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of highquality gasoline and 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 a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
high-quality unleaded gasoline!
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
with a manually adjustable carburetor
and should not be used in such engines.
The ethanol content in gasoline affects
engine running speed – it may be
necessary to readjust the carburetor if
you use fuels with various ethanol
contents.
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HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
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 shows an incorrect
idle adjustment, have your STIHL dealer
check your power tool and make 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.
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke
engine oils that are designed for use
only in air cooled two-cycle engines.
We recommend STIHL HP Ultra 2-Cycle
Engine Oil since it is specially
formulated for use in STIHL engines.
Do not use BIA or TCW rated (twostroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chain saws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the 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.
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 3 months 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 mixing of the oil
with the fuel.
Gasoline
US gal. US fl.oz.
12.6
2 1/2 6.4
5 12.8
Dispose of empty mixing-oil containers
only at authorized disposal locations.
Oil (STIHL 50:1 or equivalent high-quality oils)
Fueling
Preparations
N Before fueling, clean the filler cap
and the area around it to ensure that
no dirt falls into the tank.
N Position the machine so that the
filler cap is facing up.
N Always thoroughly shake the
mixture in the canister before
fueling your machine.
In order to reduce the risk of burns
or other personal injury from
escaping gas vapor and fumes,
remove the fuel filler cap carefully
so as to allow any pressure buildup in the tank to release slowly.
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English
Opening the cap
N Swing the grip 90° to the upright
position.
N Turn the cap counterclockwise
(about a quarter turn).
N Remove the filler cap.
Fueling
Take care not to spill fuel while fueling
and do not overfill the tank.
Closing the cap
N Insert the cap in the opening – with
the grip upright – the marks must
line up.
N Turn cap clockwise as far as stop
(about a quarter turn).
N Fold the grip down so that it is flush
with the top of the cap.
If the grip does not lie completely flush
with the cap and the lug on the grip does
not engage the recess in the filler neck
(arrow), the cap is not properly seated
and tightened and you must repeat the
above steps.
Change the fuel pickup body
Change the fuel pickup body once every
year.
N Drain the fuel tank.
N Use a hook to pull the fuel pickup
body out of the tank and take it off
the hose.
Do not kink the fuel hose – do not
use any sharp or pointed tools.
N Push the new pickup body into the
hose.
N Place the pickup body in the tank.
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HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
Rear Handle Starting / Stopping the
443BA038 KN
443BA039 KN
Engine
N Observe safety precautions – see
chapter on "Safety Precautions and
Working Techniques".
The rear handle can be turned through
90° to the left or right for better control
and comfort in all cutting situations.
N Let go of the throttle trigger. Do not
open the throttle.
N Release the lock (1).
N Turn the handle (2) to the required
position and re-engage the lock (1).
The throttle trigger may be used again
when the handle is locked in position.
Do not operate the throttle while the
handle lock is released. Never release
the lock while you are operating the
throttle.
N Move the stop switch (1) to I.
N Press down the throttle lockout (2)
and squeeze the throttle trigger (3)
at the same time – hold both levers
in that position.
N Press in the starting throttle
button (4).
N Let go of the lockout lever, throttle
trigger and starting throttle button.
This is the starting throttle position.
N Set the choke lever (5) to
g if the engine is cold
e for warm start – also use this posi-
tion if the engine has been running
but is still cold.
English
N Press the fuel pump bulb at least
five times – even if the bulb is filled
with fuel.
Starting
N Place the unit on the ground.
N Remove the blade scabbard. Check
that the cutting blades are not
touching the ground or any other
obstacles.
N Make sure you have a safe and
secure footing.
N Hold the unit firmly with your left
hand on the fan housing and press
down.
N Hold the starter grip with your right
hand.
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English
1
443BA040 KN
2
Version without Easy2Start
N Pull the starter grip slowly until you
feel it engage and then give it a brisk
strong pull.
Do not pull out the starter rope all
the way – it might otherwise
break.
N Do not let the starter grip snap back.
Guide it slowly back into the housing
so that the starter rope can rewind
properly.
Version with Easy2Start
N Pull the starter grip steadily.
When the engine begins to fire:
N Move the choke lever to e and
continue cranking.
As soon as the engine runs
N Open the throttle wide – the starting
throttle button pops out and the
engine can settle down to idle
speed.
Stopping the engine
Other hints on starting
At very low outside temperatures –
warm up the engine
As soon as the engine runs:
N Allow engine to run in starting
throttle position for about 10
seconds.
N Open the throttle wide – the starting
throttle button pops out and the
engine can settle down to idle
speed.
If the engine does not start
If you did not turn the choke lever to e
quickly enough after the engine began to
fire, the combustion chamber is flooded.
N Set the choke lever to e – even if
the engine is cold.
N Now start the engine with a few
brisk pulls of the starter rope.
If fuel tank has been run completely
dry and then refueled
N Press the fuel pump bulb at least
five times – even if the bulb is filled
with fuel.
N Now start the engine.
Cleaning the Air Filter
The unit is equipped with either a felt or
paper filter element.
If there is a noticeable loss of engine
power
Felt filter
N Turn the choke lever to g
N Take out the screw (1).
N Remove the filter cover (2).
N Clean away loose dirt from around
the filter.
N Remove the filter element (3).
N Fit a new filter element. As a
temporary measure you can knock it
out on the palm of your hand or blow
it out with compressed air. Do not
wash.
N Install the filter element.
N Fit the filter cover.
N Insert the screw and tighten it down
firmly.
N Move the stop switch to 0.
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1
443BA034 KN
2
443BA035 KN
3
443BA036 KN
Paper filter
N Turn the choke lever to g
N Take out the screw (1).
N Remove the filter cover (2).
N Clean away loose dirt from around
the filter and inside the filter cover.
Engine Management
Exhaust emissions are controlled by the
design of the fundamental engine
parameters and components (e.g.
carburation, ignition, timing and valve or
port timing) without the addition of any
major hardware.
N Position filter cover against the left
side of the filter housing and swing it
to the right – the two lugs (arrows)
must engage the filter cover
openings.
N Insert the screw and tighten it down
firmly.
N Remove and check the filter
element (3) – replace if dirty or
damaged.
N Fit the filter in the filter housing.
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English
L
H
LA
443BA037 KN
Adjusting the Carburetor
General information
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
With this carburetor it is only possible to
adjust the high speed screw within fine
limits.
Standard setting
N Stopping the engine
N Check the air filter and clean or
replace if necessary.
N Check the spark arresting screen
(country-specific) in the muffler and
clean or replace if necessary.
N Turn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
N Carefully turn the low speed
screw (L) down onto its seat
(clockwise).
N Open the low speed screw (L) one
full turn.
Readjust idle
Engine stops while idling
N Check the standard setting.
N Turn the idle speed screw (LA)
clockwise until the cutting blades
begin to run – then back it off
2 1/2 turns.
Cutting blades run when engine is
idling
N Check the standard setting.
N Turn the idle speed screw (LA)
counterclockwise until the cutting
blades stop moving – then turn it
another 2 1/2 turns in the same
direction.
Erratic idling behavior, poor
acceleration
N Check the standard setting.
N Idle setting is too lean: Rotate the
low speed screw (L) about 1/4 turn
counterclockwise until the engine
runs and accelerates smoothly.
Machine stops when it is swung at
idle speed
N Check the standard setting.
N Idle setting is too lean: Rotate the
low speed screw (L) about 1/4 turn
counterclockwise until the engine
idles smoothly.
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
Fine Tuning for Operation in
Mountains or at Sea Level
A slight correction of the setting of the
high speed screw (H) may be necessary
if engine power is not satisfactory when
operating at high altitude or at sea level.
N Check the standard setting.
N Warm up the engine.
N Adjust idle speed properly.
At high altitude
N Turn high speed screw (H)
clockwise (leaner) – no further than
stop.
At sea level
N Turn high speed screw (H) slightly
counterclockwise (richer) – no
further than stop.
If the setting is too lean there is a
risk of engine damage due to
insufficient lubrication and
overheating.
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HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
000BA002 KN
Spark Arresting Screen in
Muffler
In some countries the muffler is
equipped with a spark arresting screen.
N Check the spark arresting screen in
the muffler after every 20 hours of
operation, or if the engine is down
on power or runs erratically at
maximum speed.
Wait for the engine to cool down
completely before performing this
work.
N Take out the screws (1).
N Remove the exhaust pipe (2).
Checking the Spark Plug
N Use a 15 mm socket wrench to
unscrew the spark arresting screen.
N Clean the spark arresting screen. If
the screen is damaged or heavily
carbonized, fit a new one.
N Refit the spark arresting screen.
N Fit the exhaust pipe.
N Fit the screws.
Wrong fuel mix (too much engine oil in
the gasoline), a dirty air filter and
unfavorable running conditions (mostly
at part throttle etc.) affect the condition
of the spark plug. These factors cause
deposits to form on the insulator nose
which may result in trouble in operation.
If engine is down on power, difficult to
start or runs poorly at idling speed, first
check the spark plug.
N Remove spark plug – see "Starting /
Stopping the Engine".
N Clean dirty spark plug.
N Check electrode gap (A) and
readjust if necessary – see
"Specifications".
N Use only resistor type spark plugs of
the approved range.
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000BA036 TR
1
Rectify problems which have caused
fouling of spark plug:
N Too much oil in fuel mix.
N Dirty air filter.
N Unfavorable running conditions,
e.g. operating at part load.
Fit a new spark plug after approx. 100
operating hours or earlier if the
electrodes are badly eroded.
Warning!
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press spark plug boot (2)
snugly onto spark plug terminal (1) of
the proper size. (Note: If terminal has
detachable SAE adapter nut, it must be
attached.) A loose connection between
spark plug boot and ignition wire connector in the boot may create arcing that
could ignite combustible fumes and
cause a fire.
Lubricating the Gearbox
Use STIHL gear lubricant for hedge
trimmers (special accessory) to lubricate
the blade drive gear.
After about 25 hours of operation:
N Remove the screw plug (1) from the
gear housing on the underside of
the unit.
N Screw the tube of grease (2) into the
filler hole.
N Squeeze up to 1/4 oz (5 g) grease
into the gearbox.
Do not completely fill the gearbox
with grease.
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HS 81 R, HS 81 RC, HS 81 T, HS 81 TC
English
N Remove the tube of grease (2).
N Refit the filler plug and tighten it
down firmly.
Rewind Starter Storing the Machine
To help prolong the wear life of the
starter rope, observe the following
points:
N Pull the starter rope only in the
direction specified.
N Do not pull the rope over the edge of
the guide bushing.
N Do not pull out the rope more than
specified.
N Do not allow the starter grip to snap
back, guide it back into the housing
slowly – see chapter on "Starting /
Stopping the Engine."
Have a damaged starter rope replaced
by your dealer before it breaks
completely. STIHL recommends that
you have servicing and repair work
carried out exclusively by an authorized
STIHL servicing dealer.
For periods of 3 months or longer
N Drain and clean the fuel tank in a
well ventilated area.
N Dispose of fuel properly in
accordance with local
environmental requirements.
N Run the engine until the carburetor
is dry – this helps prevent the
carburetor diaphragms sticking
together.
N Clean the cutting blades, check
condition and spray with STIHL
resin solvent.
N Fit the blade scabbard.
N Thoroughly clean the machine –
pay special attention to the cylinder
fins and air filter.
N Store the machine in a dry, high or
locked location. Out of the reach of
children and other unauthorized
persons.
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