HS 80
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STIHL HS 75, 80
STIH)
Instruction Manual
Manual de instrucciones
Warning!
For safe operation follow all safety
precautions in Instruction Manual - improper
use can cause serious injury.
Advertencia!
Para su seguridad durante el manejo de este
producto, siga siempre las precauciones de
seguridad dadas en el manual de
instrucciones - el uso indebido puede causar
lesiones graves.
Contents
English / USA
Guide to Using this Manual .............. 2
Safety Precautions ........................... 3
Using the Unit ................................. 10
Fuel ................................................ 11
Fueling ............................................ 12
Rear Handle ................................... 13
Starting / Stopping
BA_SE_055_004_01_03.fmPrinted on chlorine-free paper.
the Engine ...................................... 13
Operating Instructions .................... 15
Cleaning the Air Filter ..................... 15
Motor Management ........................ 16
Adjusting the Carburetor ................ 16
Spark Arresting Screen
in Muffler ......................................... 17
Checking the Spark Plug ................ 18
Lubricating Gearbox ....................... 19
Replacing the Starter Rope
and Rewind Spring ......................... 19
Storing the Machine ........................ 22
Sharpening Instructions .................. 22
Maintenance Chart ......................... 23
Parts and Controls .......................... 24
Specifications ................................. 26
Special Accessories ....................... 27
Maintenance and Repairs ............... 27
STIHL Incorporated Federal and
Printing inks contain vegetable oils; paper can be recycled.
California Emission Control
Warranty Statement ........................ 28
Allow only persons who 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 and
understand the maintenance and safety
precautions, starting on page 3, before
using your hedge trimmer.
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.
STIHL's philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements are made from time to time. If the
operating characteristics or the appearance of your hedge trimmer differs from
those described in this manual, please
contact your STIHL dealer for
information and assistance.
STIHl
© ANDREAS STIHL AG & Co. KG, 2003
0458 366 3021. M2. L3. CP. Printed in USA
1HS 75, HS 80
English / USA
Guide to Using this Manual
Pictograms
All the pictograms attached to the
machine are shown and explained in
this manual.
The operating and handling instructions
are supported by illustrations.
Symbols in text
The individual steps or procedures
described in the manual may be marked
in different ways:
: Step or procedure without direct
reference to an illustration.
Description of step or procedure that
refers directly to the illustration and
contains item numbers that appear in
the illustration.
Example:
Loosen the screw (1)
Lever (2) ...
In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are marked with the
symbols described below:
Warning where there is a risk of an
accident or personal injury or
serious damage to property.
Warning where there is a risk of
damaging the machine or individual
components.
Note or hint which is not essential
for using the machine, but may
improve the operator’s understanding of the situation and result
in better use of the machine.
Note or hint on correct procedure in
order to avoid damage to the
environment.
Equipment and features
This instruction manual refers to
several models with different
features. Components that are not
installed in all models and related
applications are marked thus *.
Such components are available as
special accessories from your
STIHL dealer.
Engineering improvements
STIHL’s philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time to time. If the
operating characteristics or the
appearance of your machine differ from
those described in this manual, please
contact your STIHL dealer for
assistance.
Therefore, we cannot be responsible for
changes, modifications or
improvements not covered in this
manual.
2
HS 75, HS 80
Safety Precautions
English / USA
Because a hedge trimmer
is a high-speed,
fast-cutting power tool,
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
owner's manual and the
safety instructions periodically.
Careless or improper use of any hedge
trimmer may cause serious or fatal
injury.
Have your STIHL dealer show you how
to operate your hedge trimmer.
Observe all applicable local safety
regulations, standards and ordinances.
!Warning!
The use of any hedge trimmer may be
hazardous. If the cutting tool comes in
contact with your body, it will cut you.
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
hedge trimmers when cutting in areas
where the blades could contact such
objects.
!Warning!
Minors should never be allowed to use a
hedge trimmer. Bystanders, especially
children, and animals should not be
allowed in the area where a hedge trimmer is in use.
The operator is responsible for avoiding
injury of third parties and damage to
their property.
Never let the hedge trimmer run
unattended.
!Warning!
Do not lend or rent your hedge trimmer
without the owner's manual. Be sure
that anyone using your hedge trimmer
understands the information contained
in this manual.
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 owner's
manual for a description of the controls
and function of the parts of your model
hedge trimmer.
Safe use of a hedge trimmer involves
1. the operator
2. the hedge trimmer
3. the use of the hedge trimmer.
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 a
hedge trimmer when you are fatigued.
Be alert - if you get tired while operating
your hedge trimmer, take a break.
Tiredness may result in loss of control.
Working with any hedge trimmer can be
strenuous. If you have any condition that
might be aggravated by strenuous work,
check with your doctor before operating
a hedge trimmer.
3HS 75, HS 80
English / USA
!Warning!
Prolonged use of a hedge trimmer (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 engine 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 hedge trimmer with
loose components or with damaged
or worn AV buffers will tend to have
higher vibration levels.
: Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressures, 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 monitor closely the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
!Warning!
The ignition system of your 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 pacemaker should consult
their physician and the pacemaker
manufacturer before operating this tool.
Proper Clothing
!Warning!
Hedge trimmer operation
can cause serious injury
to eyes, ears and person.
Therefore, to reduce the
risk of injury to your eyes
never operate a hedge
trimmer unless wearing goggles or
properly fitted safety 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 safety glasses.
!Warning!
Hedge trimmer 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.
4
HS 75, HS 80
English / USA
3
Wear proper protective
clothing. Clothing must be
sturdy and snug-fitting,
but allow complete
freedom of movement.
Avoid loose- fitting jackets,
scarfs, neckties, jewelry, flared or cuffed
pants, unconfined long hair or anything
that could become caught on branches,
brush or moving parts of the unit. Wear
long pants made of heavy material to
protect your legs.
Do not wear shorts.
Protect your hands with
gloves when handling the
hedge trimmer and the
cutting tool. Heavy-duty,
nonslip gloves improve
your grip and help to
protect your hands.
Good footing is most
important in hedge
trimmer work. Wear
sturdy boots with nonslip
soles. Steeltoed safety
boots are recommended.
Wear an approved safety hard hat to
reduce the risk of injury to your head
when there is a danger of head injuries.
THE HEDGE TRIMMER
For illustrations and definitions of the
hedge trimmer parts see the chapter on
"Parts and Controls"!
!Warning!
Never modify a hedge trimmer in any
way. Only attachments supplied by
STIHL or expressly approved by STIHL
for use with the specific STIHL hedge
trimmer models are authorized.
Although certain unauthorized attachments are useable for the STIHL hedge
trimmer, their use may, in fact, be
extremely dangerous.
THE USE OF THE HEDGE
TRIMMER
Transporting the hedge trimmer
To reduce the risk of injury from blade
contact, never carry or transport the
hedge trimmer with the cutter blades
running. The correct engine idle speed
is important in this respect. If the carburetor setting is correct, the cutter blades
will be stationary at idle speed.
Always engage the starting lock before
transporting the machine (see chapter
"Starting"). The starting lock may only be
engaged when the cutter blades are at a
standstill.
66BA001 LÄ
The hedge trimmer may be carried only
in the normal upright position. Grip the
front handle and keep the cutter blades
behind you.
Always switch off the engine and fit the
scabbard over the cutter blades before
transporting the hedge trimmer over
long distances.
When transporting your hedge trimmer
in a vehicle, properly secure it to prevent
turnover, fuel spillage and damage to the
hedge trimmer.
5HS 75, HS 80
English / USA
Preparation for the use of the
hedge trimmer
!Warning!
Always check your hedge trimmer for
proper condition and operation before
starting, particularly the throttle trigger,
throttle trigger interlock, stop switch,
cutting tool and starting lock. The throttle
trigger must move freely and always
spring back to the idle position.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!
Service damaged cutter blades before
using the hedge trimmer. Always keep
blades sharp. Keep the handles clean
and dry at all times; it is particularly
important to keep them free of oil and
resin to ensure that you can always
maintain a firm grip and safely control
your machine.
!Warning!
Removal of safety devices can lead to
serious injury.
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.
Fueling
Your STIHL hedge trimmer uses an
oil-gasoline mixture for fuel (see the
chapter on "Fuel" of your owner's
manual).
!Warning!
Gasoline is an extremely
flammable fuel. If spilled
or ignited by a spark or
other ignition source, it
can cause fire and serious
burn injury or property
damage.
Use extreme caution when handling
gasoline or fuel mix.
Do not smoke or bring any fire or flame
near the fuel.
Fueling Instructions
Fuel your hedge trimmer in
well ventilated areas, outdoors.
!Warning!
Gasoline vapor pressure may build up
inside the gas tank of a two cycle engine
depending on the fuel used, the weather
conditions, and the venting system of
the tank. In order to reduce the risk of
burns or other personal injury from
escaping gas vapor and fumes, remove
the fuel filler cap on your hedge trimmer
carefully so as to allow any pressure
build-up in the tank to release slowly.
Never remove fuel filler cap while
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 hedge trimmer and check for
leakage.
Check for fuel leakage while refueling
and during operation. If fuel leakage is
found, do not start or run the engine until
leak is fixed and spilled fuel has been
wiped away. Take care not to get fuel on
your clothing. If this happens,
change your clothing immediately.
Never attempt to fuel a running or hot
engine.
6
HS 75, HS 80
English / USA
!Warning!
Unit vibrations can
cause an improperly
tightened fuel cap to
loosen or come off and
spill quantities of fuel.
In order to reduce risk of
fuel spillage and fire, tighten fuel cap by
hand with as much force as possible.
Starting
!Warning!
Your hedge trimmer is a one-person
machine. Start and operate your hedge
trimmer without assistance.
!Warning!
To reduce the risk of injury from blade
contact, do not attempt to "drop start"
your hedge trimmer. For specific
starting instructions, see the appropriate section of your manual.
Place the hedge trimmer on firm ground
or other solid surface in an open area.
Maintain a good balance and secure
footing. To reduce the risk of injury from
blade contact or loss of control always
engage the starting lock before starting.
When the engine starts at startingthrottle, engine speed will be fast
enough for the clutch to engage and
move the cutting tool.
When you pull the starter grip, don't
wrap the starter rope around your hand.
Do not allow the grip to snap back, but
guide the starter rope to rewind properly.
Failure to follow this procedure may
result in injury to hand or fingers and
may damage the starter mechanism.
Working Conditions
!Warning!
To reduce the risk of injury
from inhalation of
poisonous fumes, operate
and start your hedge
366BA036 LA
Hold your hedge trimmer in such a way
that you do not breathe in the exaust
fumes. Operate the hedge trimmer
under good visibility and daylight
conditions only.
Work carefully. Take particular care in
slippery conditions and on slopes.
Be careful on uneven ground. Watch out
for stumps, roots, ditches or holes which
could cause you to trip or stumble.
Before you start work, examine the
hedge area for stones, fence wire, metal
or other solid objects which could
damage the cutter blades.
trimmer only outdoors in a
ventilated area.
7HS 75, HS 80
English / USA
Operating instructions
Do not cut any material other than
hedges and shrubs. The cutting tools
may be used only for the operations
described in your manual.
!Warning
To reduce the risk of injury from loss of
control, always hold your hedge trimmer
firmly with both hands while you are
working.
Your right hand should grip the rear
handle. This also applies to left-handers.
Wrap your fingers tightly around the
front and rear handles.
!Warning
Never attempt to operate any hedge
trimmer with one hand. Loss of control of
the hedge trimmer resulting in serious or
fatal injury may result.
Make sure you always have good
footing. Always work calmly and
carefully, stay alert so as not to
endanger others.
When working close to the ground,
make sure that no sand, grit or stones
get between the cutter blades.
If the cutter blades become jammed by
thick branches or any other obstruction,
switch off the engine immediately
before attempting to free the blades.
!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 use the hedge trimmer above
shoulder height or with one hand.
!Warning
The cutter blades tend to run on for a
short period after the throttle
trigger is released (flywheel effect).
366BA037 LA
Important adjustments
!Warning
To reduce the risk of personal injury from
loss of control or contact with the
running cutting blades, do not use a
hedge trimmer with incorrect idle
adjustment.
At correct idle speed, the cutting blades
should not move. For directions to
adjust idle speed, see the appropriate
section of your owner's manual.
If you cannot set the correct idle speed,
have your STIHL dealer check your
hedge trimmer and make proper
adjustments or repairs.
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 claim
warranty for a component which has
not been serviced or maintained properly or if nonapproved replacement
parts were used, STIHL may deny
warranty.
Use only STIHL replacement parts for
maintenance and repair. Use of parts
manufactured by others may cause
serious or fatal injury.
Follow the maintenance and repair
instructions in the appropriate section of
your owner's manual. Refer to the
maintenance chart at the last pages of
this manual.
8
HS 75, HS 80
English / USA
!Warning
Always stop the engine and make sure
that the cutting tool is stopped before
doing any maintenance or repair work or
cleaning the hedge trimmer. Do not
attempt any maintenance or repair work
not described in your owner's manual.
Have such work performed at your
STIHL service shop only.
!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.
Check condition of cutting tool at regular
short intervals. If behavior of tool
changes, check it immediately for
tightness or any signs of cracks in
particular. Replace damaged or dull
cutting tools immediately, even if they
have only superficial cracks.
!Warning
Never test the ignition system with
ignition wire terminal removed from
spark plug or with unseated spark plug,
since uncontained sparking may cause
a fire.
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. 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
attached.) A loose connection between
spark plug terminal and ignition wire
connector in the boot may create arcing
that could ignite combustible fumes and
cause a fire. Keep spark plug clean, and
make sure ignition lead is in good
condition.
!Warning
To reduce the risk of fire, check fuel filler
cap for leaks at regular intervals.
Always clean dust and dirt off the
machine after finishing work. Do not use
a grease solvent for cleaning!
An aerosol can of resin solvent (protective spray), Part No. 0782 420 1002, is
available for spraying the cutter blades.
This resin solvent protects the cutter
blades and has anticorrosive properties.
Spray the cutter blades before and
after work. Then start and run the hedge
trimmer briefly so that the resin solvent
is evenly distributed over the blades.
If the hedge itself is very dusty and dirty,
spray the cutter blades more frequently.
This greatly reduces blade friction and
the damaging effects of sap and dust
particles.
!Warning
Do not operate your hedge trimmer if the
muffler is damaged, missing or modified.
An improperly maintained muffler will increase the risk of fire and hearing loss.
Never touch a hot muffler or burn will
result. If your muffler was equipped with
a spark-arresting screen to reduce the
risk of fire (e.g. in the USA, Canada and
Australia), never operate your hedge
trimmer if the screen is missing or
damaged. Remember that the risk of
forest fires is greater in hot or dry
weather. Keep the engine and muffler
free from cuttings, chips, leaves, fibers
and excess lubricant.
9HS 75, HS 80
English / USA
Using the Unit
!Warning
In order to reduce the risk of fire, do not
modify or remove any part of the muffler
or spark arresting.
Keep cutting tool sharp. Tighten all nuts,
bolts and screws except the carburetor
adjustment screws after each use.
Keep spark plug and wire connection
tight and clean. The spark plug electrode
gap should be checked with a feeler
gauge at least every 50 operating hours
and reset if necessary. Fit a new spark
plug if the electrodes are badly pitted.
For any maintenance please refer to the
maintenance chart and to the warranty
statement near the end of this manual.
Store hedge trimmer in a dry, high or
locked location out of reach of children.
Before storing for longer than a few
days, always empty the fuel tank.
Cutting season
Observe all country-specific and local
regulations and ordinances regarding
hedge trimming.
Do not use your hedge
trimmer during other
people's rest periods.
Preparations
Before starting work,
scare away small animals
so that they cannot be
injured.
Use lopping shears to cut out thick
branches first.
Cutting sequence
If a radical cut is necessary, cut a little at
a time in several passes.
Cut both sides of the hedge first, then
the top.
366BA024 KN
Cutting techniques
Vertical cut:
Swing the cutting blade up and down in
an arc as you move along the hedge use both sides of the cutting blade.
10
HS 75, HS 80
Fuel
English / USA
0 - 10°
Horizontal cut:
Hold the cutting blade at an angle of
0° to 10° as you swing the hedge
trimmer horizontally.
Swing the blade in an arc towards the
outside of the hedge so that the cuttings
are swept on to the ground.
Do not throw cuttings in
the rubbish bin (garbage
can) - they can be
composted!
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your two-stroke engine requires a
mixture of high-quality gasoline and
quality two-stroke air cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2). If
the octane rating of the mid-grade
gasoline in your area is lower, use
premium unleaded fuel.
Fuel with a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
366BA025 KN
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
nationally recognized high-quality
unleaded gasoline!
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke
engine oils that are designed for use
only in air cooled two-cycle engines.
We recommend STIHL 50:1 two-stroke
engine oil since it is specially formulated
for use in STlHL engines.
Do not use BIA or TCW rated (twostroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chainsaws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the canister from
your vehicle and place the canister on
the ground before filling. Do not fill fuel
canisters that are sitting in or on a
vehicle.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The machine‘s fuel tank and the canister
in which fuel mix is stored should be
cleaned as necessary.
11HS 75, HS 80
English / USA
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 3 months of storage.
Store in approved fuel-canisters only.
When mixing, pour oil into the canister
first, and then add gasoline. Close the
canister and shake it vigorously by hand
to ensure proper mixing of the oil with
the fuel.
Gasoline
Oil (STIHL 50:1 or
equivalent high-quality oils)
US gal. US fl.oz
12.6
2 1/2 6.4
512.8
Fueling
366BA006 KN
366BA007 KN
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
12
Before fueling, clean the filler cap and
the area around it to ensure that no dirt
falls into the tank.
Always thoroughly shake the mixture in
the canister before fueling your
machine.
In order to reduce the risk of burns
or other personal injury from
escaping gas vapor and fumes,
remove the fuel filler cap carefully
so as to allow any pressure build-up
in the tank to release slowly.
After fueling, tighten fuel cap
as securely as possible by hand.
Change the fuel pick up body
every year.
Before storing your machine for a long
period, drain and clean the fuel tank and
run engine until carburetor is dry.
HS 75, HS 80
English / USA
Rear Handle
(HS 80 only)
2
1
The rear handle can be turned 90° to the
left or right for better control and comfort.
Let go of throttle trigger Do not open the throttle
: Release the twist lock (1).
Turn the handle (2) as required and
allow twist lock to snap into position.
: Make sure the handle is locked
before opening the throttle.
Do not operate the throttle while the twist
lock is released. Do not release the twist
lock while you are operating the throttle.
90°
Starting / Stopping the Engine
366BA039 KN
: Observe safety precautions.
: Move the blade lock lever (1) to
position z.
: Squeeze the throttle trigger (2) and
move the slide control (3) to n at
the same time.
: Release the throttle trigger.
: Let go of the slide control. This is the
starting throttle position.
4
366BA031 LA
: Set the choke lever (4):
For cold start to g
For warm start to e
Also use this setting if engine has
been running but is still cold.
4
366BA010 KN
5
: Press the fuel pump bulb (5) at least
five times.
13HS 75, HS 80
366BA011 KN
English / USA
: Put the unit on the ground with the
rewind starter facing up. Make sure
it is secure.
: Remove the blade scabbard before
starting.
: Make sure you have a firm footing:
Hold the unit with you left hand on
the front handle and press it down
firmly.
: Pull the starter rope slowly with your
right hand 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.
: Do not let the starter grip snap back
– guide it slowly into the housing so
that the starter rope can rewind
properly.
When engine begins to fire:
: Move the choke lever to e and
continue cranking.
As soon as engine runs, blip the
throttle trigger, the slide control
moves to the run position # and
the engine settles down to idle
366BA036 LA
speed.
: Move the blade lock lever to y.
To shut down the engine:
: Move the slide control to O.
At very low outside temperatures:
As soon as engine runs:
: Blip the throttle trigger –
the slide control moves to the run
position # – and the engine settles
down to idle speed.
: Open the throttle part way and warm
up engine for a brief period.
If the engine doesn’t start:
If you did not move the choke lever to
e quickly enough after the engine
began to fire, the combustion chamber is
flooded.
367BA013 LA
: Pull off the spark plug boot (7).
: Unscrew and dry off the spark plug.
: Set slide control to O.
: Open the throttle wide.
: Crank the engine several times with
the starter to clear the combustion
chamber.
: Refit the spark plug.
: Connect the spark plug boot (press
it down firmly).
: Set slide control to #
: Set choke lever to e even if
engine is cold.
: Now start the engine.
Fuel tank run dry and then
refueled:
: Press the fuel pump bulb (5) at least
fives times.
: Now start the engine.
14
HS 75, HS 80
Operating Instructions Cleaning the Air Filter
During break-in period
A factory new machine should not be run
at high revs (full throttle off load) for the
first three tank fillings. This avoids
unnecessary high loads during the
break-in period. As all moving parts
have to bed in during the break-in
period, the frictional resistances in the
engine are greater during this period.
The engine develops its maximum
power after about 5 to 15 tank fillings.
During operation
After a long period of full-throttle
operation, allow engine to run for a while
at idle speed so that the heat in the
engine can be dissipated by flow of
cooling air. This protects enginemounted components (ignition,
carburetor) from thermal overload.
After finishing work
Wait for engine to cool down. Drain the
fuel tank. Store the machine in a dry
place. Check tightness of nuts and
screws (not adjusting screws) at regular
intervals and retighten as necessary.
1
Dirty air filters reduce engine power,
increase fuel consumption and make
starting more difficult.
If there is a noticeable loss of
engine power
: Move choke lever to g
: Press in the tab (1).
: Ease the filter cover (2) over the
tab and take it away.
: Clean away loose dirt from around
the filter.
: Remove the foam and felt filter
elements.
2
English / USA
2
3
4
326BA015 KN
: Wash the foam element in a clean,
non-flammable cleaning solution
(e.g. warm soapy water) and then
dry.
: Fit new felt 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.
Replace damaged parts.
: Install the foam element (3) in the
filter cover (2).
: Place felt element (4) (lettering
facing inward) in filter housing (5).
: Fit filter cover so that it snaps into
position.
355BA031 KN
5
355BA032 KN
15HS 75, HS 80
English / USA
Motor Management Adjusting the Carburetor
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.
Your carburetor does not have a high
speed adjusting screw (H screw).
Adjustment of maximum engine speed is
not necessary.
The carburetor is set at the factory to
provide an optimum fuel-air mixture
under most operating conditions.
Idling and part-load emissions are
minimized by limiting the idle mixture.
: Check the cutting blades and clean
if necessary (they must be clean,
move freely and not be bent or
warped).
: Check the air filter and clean it if
necessary.
: Warm up the engine.
: Carefully screw the low speed
screw (L) down onto its seat. Then
open it one turn counterclockwise
(standard setting, L = 1).
16
HS 75, HS 80
Spark Arresting Screen in Muffler
English / USA
Adjusting Idle Speed
Engine stops while idling:
Check standard setting.
(L screw must be one turn open)
: Turn idle speed screw (LA) slowly
clockwise until the cutting blades
start running and then turn one half
turn counterclockwise.
Cutting blades run when engine is
idling:
Check standard setting.
(L screw must be one turn open)
: Turn idle speed screw (LA) slowly
counterclockwise until the cutting
blades stop running at idle speed
and turn the screw about another
one half turn in the same direction.
1
2
If the engine is low on power, check the
spark arresting screen* inside the
muffler.
Warning: Wait for the engine to cool
down completely before performing this
work.
: Remove the shroud.
Take out the screw (1).
: Remove the spark arresting
screen (2).
: Clean spark arresting screen if
necessary.
: If screen is damaged or coked up, fit
a new one.
: Refit the spark arresting screen.
: Fit the shroud.
366BA026 KN
366BA027 KN
* see “Guide to Using this Manual”
17HS 75, HS 80
English / USA
0
Checking the Spark Plug
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.
: Remove spark plug – see “Starting /
Stopping the Engine“.
: Clean dirty spark plug.
: Check electrode gap (A) and
readjust if necessary – see
"Specifications".
: Use only resistor type spark plugs
of the approved range.
Rectify problems which have caused
fouling of spark plug:
: Too much oil in fuel mix.
: Dirty air filter.
: Unfavorable running conditions,
000BA002 KN
e.g. operating at part load.
Fit a new spark plug after approx.
100 operating hours
or earlier if the electrodes are badly
eroded.
1
00BA036 TR
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.
18
HS 75, HS 80
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