Stihl Hs 81 R Manual

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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 
						

							Original Instruction Manual Printed on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled. © 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 TCEnglish
1
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Contents
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. 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
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
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 32Warning!
Because a hedge trimmer 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. 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TC 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:
NA 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. Example:
NLoosen the screw (1).
NLever (2) ...
In addition to the operating instructions, 
this manual may contain paragraphs 
that require your special attention. Such 
paragraphs are marked with the 
symbols and signal words described 
below:
Engineering Improvements
STIHL’s philosophy is to continually 
improve all of its products. As a result, 
engineering changes and improvements 
are made from time to time. Therefore, 
some changes, modifications and 
improvements may not be covered in 
this manual. If the operating 
characteristics or the appearance of your machine differs from those 
described in this manual, please contact 
your STIHL dealer for assistance.
Guide to Using this Manual
Fuel tank for gasoline 
and engine oil mixture
Press to operate manual 
fuel pump
Filler hole for gear 
lubricant
Starting lock
Rotating rear handle
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. 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TCEnglish
3 Have your STIHL dealer show you how 
to operate your power tool. Observe all 
applicable local safety regulations, 
standards and ordinances.
Use your hedge trimmer only for cutting 
hedges, shrubs, scrub, bushes and 
similar material.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.
These conditions reduce the hands 
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 Safety Precautions and 
Working Techniques
Because a hedge trim-
mer is a high-speed, fast-
cutting power tool 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.
Warning!
Do not lend or rent your power tool with-
out the instruction manual. Be sure that 
anyone using it understands the infor-
mation contained in this manual.
Warning!
The use of this machine may be hazard-
ous. If the cutting tool comes in contact 
with your body, it will cut you.
Warning!
Do not use it for other purposes, since 
misuse may result in personal injury or 
property damage, including damage to 
the machine.
Warning!
Minors should never be allowed to use 
this power tool. Bystanders, especially 
children, and animals should not be 
allowed in the area where it is in use.
Warning!
To reduce the risk of injury to bystand-
ers and damage to property, never let 
your power tool run unattended. When it 
is not in use (e.g. during a work break), 
shut it off and make sure that unauthor-
ized persons do not use it.
Warning!
Be alert – if you get tired, take a break. 
Tiredness may result in loss of control. 
Working with any power tool can be 
strenuous. If you have any condition 
that might be aggravated by strenuous 
work, check with your doctor before 
operating this machine.
Warning!
Prolonged use of a power tool (or other 
machines) exposing the operator to 
vibrations may produce whitefinger dis-
ease (Raynauds phenomenon) or 
carpal tunnel syndrome. 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TC English
4 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 
operators hands. An AV system is 
recommended for those persons 
using power tools on a regular or 
sustained basis.
–Wear gloves and keep your hands 
warm.
–Keep the AV system well 
maintained. A power tool with loose 
components or with damaged or 
worn AV elements will tend to have 
higher vibration levels.
–Maintain a firm grip at all times, but 
do not squeeze the handles with 
constant, excessive pressure. Take 
frequent breaks.
All the above-mentioned precautions do 
not guarantee that you will not sustain 
whitefinger disease or carpal tunnel 
syndrome. Therefore, continual and 
regular users should closely monitor the 
condition of their hands and fingers. If 
any of the above symptoms appear, 
seek medical advice immediately.Proper Clothing
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!
The ignition system of the STIHL unit 
produces an electromagnetic field of a 
very low intensity. This field may inter-
fere with some pacemakers. To reduce 
the risk of serious or fatal injury, persons 
with a pacemaker should consult their 
physician and the pacemaker manufac-
turer before operating this tool.
Warning!
To reduce the risk of injury, the operator 
should wear proper protective apparel.
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 com-
plying 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.
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.
Good footing is very 
important. Wear sturdy 
boots with nonslip soles. 
Steel-toed safety boots 
are recommended. 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TCEnglish
5 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 ToolIt 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.
Fuel
Your STIHL power tool uses an oil- 
gasoline mixture for fuel (see the 
chapter on Fuel of your instruction 
manual.)Fueling Instructions
In order to reduce the risk of burns and 
other personal injury from escaping gas 
vapor and fumes, remove the fuel filler 
cap on your power tool carefully so as to 
allow any pressure build-up in the tank 
to release slowly. Never remove the fuel 
filler cap while the engine is running.
Select bare ground for fueling and move 
at least 10 feet (3 m) from the fueling 
spot before starting the engine. Wipe off 
any spilled fuel before starting your 
machine. 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 unauthor-
ized attachments are useable with 
STIHL power tools, their use may, in 
fact, be extremely dangerous.
Warning!
To reduce the risk of injury from blade 
contact, never carry or transport your 
power tool with the cutter blades 
moving.
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.
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.
Warning!
Fuel your power tool in well-ventilated 
areas, outdoors. Always shut off the 
engine and allow it to cool before refu-
eling. Gasoline vapor pressure may 
build up inside the fuel tank depending 
on the fuel used, the weather conditions 
and the tank venting system. 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TC English
6 Different models may be equipped with 
different fuel caps.
Toolless cap with grip
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).Misaligned, damaged or broken cap
NIf 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.NTo 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.
NIf 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
See also the Fueling chapter in your 
Instruction Manual for additional 
information. Warning!
Check for fuel leakage 
while refueling and dur-
ing 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 cloth-
ing. If this happens, change your 
clothing immediately.
Warning!
In order to reduce the risk of fuel spill-
age and fire from an improperly 
tightened fuel cap, correctly position 
and tighten the fuel cap in the fuel tank 
opening.
001BA220 KN
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 correspond-
ing 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.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
001BA227 KN
Warning!
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.
001BA226 KN 
						

							HS 81 R, HS 81 RC, HS 81 T, HS 81 TCEnglish
7 Before Starting
Keep the handles clean and dry at all 
times; it is particularly important to keep 
them free of moisture, pitch, oil, fuel mix, 
grease or resin in order for you to 
maintain a firm grip and properly control 
your power tool.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.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.
Important Adjustments 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.
Warning!
The cutting tool must be properly tight-
ened 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.
Warning!
To reduce the risk of injury from blade 
contact, be absolutely sure that the cut-
ting 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.
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.
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 English
8 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.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!
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, over-
grown terrain. Watch for hidden 
obstacles such as tree stumps, roots 
and ditches to avoid stumbling. For bet-
ter footing, clear away fallen branches, 
scrub and cuttings. Be extremely cau-
tious 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.Warning!
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 respiratory prob-
lems, cancer, birth defects, or other 
reproductive harm. Some of the gases 
(e.g. carbon monoxide) may be color-
less and odorless. To reduce the risk of 
serious or fatal injury / illness from inhal-
ing toxic fumes, never run the machine 
indoors or in poorly ventilated locations.
Warning!
If the vegetation being cut or the sur-
rounding ground is coated with a 
chemical substance (such as an active 
pesticide or herbicide), read and follow 
the instructions and warnings that 
accompanied the substance at issue.