STIHL HL 45 Owner's Manual

STIHL HL 45

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 and

Working Techniques ......................... 3

Applications .................................... 12

Assembling the Unit ....................... 13

Fuel ................................................ 14

Fueling ............................................ 15

BA_SE_014_003_01_05.fmPrinted on chlorine-free paper.

Starting / Stopping .......................... 15

Cleaning the Air Filter ..................... 17

Motor Management ........................ 18

Adjusting the Carburetor ................ 18

Catalytic Converter*......................... 20

Checking the Spark Plug ................ 20

Lubricating the Gearbox ................. 21

Rewind Starter ................................ 22

Sharpening Instructions .................. 22

Operating Instructions .................... 22

Storing the Machine ........................ 23

Maintenance Chart ......................... 24

Inspections and Maintenance by

STIHL Service ................................ 25

Parts and Controls .......................... 26

Specifications ................................. 28

Maintenance and Repairs ............... 29

For California only:
STIHL Incorporated

Printing inks contain vegetable oils; paper can be recycled.

California Exhaust and
Evaporative Emissions

Control Warranty Statement ........... 30

Not for California:
STIHL Incorporated Federal
Emission Control

Warranty Statement ........................ 33

Allow only persons who understand this
manual to operate your hedge cutter.

To receive maximum performance and
satisfaction from your STIHL hedge
cutter, it is important that you read and
understand the maintenance and safety
precautions, starting on page 3, before
using your hedge cutter.

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 cutter 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.

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 cutter differs
from those described in this manual,
please contact your STIHL dealer for
information and assistance.

STIHl

© ANDREAS STIHL AG & Co. KG, 2006

0458 405 8621. M0.5. J6. PM.. Printed in USA

1HL 45

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:

: A bullet marks a step or procedure

without direct reference to an
illustration.

A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration.
Example:

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.

Caution where there is a risk of
damaging the machine or its
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 may refer to
several models with different
features. Components that are not
installed on all models and related
applications are marked with an
asterisk (*). Such components may
be 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 some changes, modifications
and improvements may not be covered
in this manual.

2

HL 45

Safety Precautions and Working Techniques

English / USA

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. It must not be used for
any other purposes, since such misuse
may result in an accident or 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.

3HL 45

English / USA

!Warning!

Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger
disease (Raynaud's phenomenon) or
carpal tunnel syndrome.

These conditions reduce the hand's
ability to feel and regulate temperature,
produce numbness and burning
sensations and may cause nerve and
circulation damage and tissue necrosis.

All factors which contribute to white­finger disease are not known, but cold
weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
disease. In order to reduce the risk of
whitefinger disease and carpal tunnel
syndrome, please note the following:

Most STIHL power tools are available
with an anti-vibration (“AV”) system
designed to reduce the transmission of
vibrations created by the machine to the
operator's hands. An AV system is
recommended for those persons using
power tools on a regular or sustained
basis.

Wear gloves and keep your hands
warm.

Keep the AV system well maintained. A
power tool with loose components or
with damaged or worn AV buffers 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 protective

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.

!Warning!

Power tool noise may

damage your hearing.

Wear sound barriers (ear

plugs or ear mufflers) to

protect your hearing.

Continual and regular
users should have their hearing checked
regularly.

Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.

4

HL 45

English / USA

Always wear gloves when
handling the machine and
the cutting tool. Heavy­duty, 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.

Wear an approved safety

hard hat to reduce the risk

of injury to your head

when there is a danger of

head injuries.

THE POWER TOOL

For illustrations and definitions of the
power tool parts see the chapter on
“Main Parts and Controls”.

!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.

389BA019 KN

It may be carried only in a horizontal
position. Grip the shaft in a manner that
the machine is balanced horizontally.
Keep the hot muffler away from your
body and the cutting attachment behind
you.

5HL 45

English / USA

!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.

On machines with an adjustable cutter
bar: Make sure the cutter bar is secured
in position. See chapter in instruction
manual entitled “Adjusting Cutter Bar
Angle.” On machines with a transport
position: Move cutter bar to transport
position and secure.

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 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 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.

!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.

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
triangular marks on the grip of the cap
and on the fuel tank opening lining up.
Using the grip, turn the cap firmly
clockwise as far as it will go (approx. a
quarter turn).

Fold the grip flush with the

top of the cap. If the grip

does not lie completely

flush with the cap and the

detent on the grip does

not fit in the
corresponding recess in the filler neck,
the cap is not properly seated and
tightened and you must repeat the
above steps.

6

HL 45

English / USA

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.

Before Starting

!Warning!

Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger interlock, 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, 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.

Adjust carrying harness and hand grip to
suit your size before starting work.

Starting

On machines with an adjustable cutter
bar: Secure the cutter bar in the starting
position as described in the chapter
“Starting/Stopping the Engine.” If this
starting position is not the desired
cutting position, you will then need to
carefully adjust the machine to the
desired position once the engine has
returned to idle and the blades are no
longer moving.

On machines with a defined transport
position (cutter bar folded against the
drive tube): Never start the machine in
the transport position, since the blades
are not engaged in that position and you
therefore cannot visually check to see
that they will be stopped at idle when
you start to adjust the cutter bar to the
desired cutting position (where the
blades are engaged).

Start the engine at least 10 feet
(3 meters) from the fueling spot,
outdoors only.

7HL 45

English / USA

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.

With the engine running only at idle,
attach the power tool to the spring hook
of your harness (see appropriate
chapter of this manual).

!Warning!

Your power tool is a one-person
machine. Do not allow other persons in
the general work area, even when
starting.

!Warning!

To reduce the risk of injury from loss of

389BA023 KN

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.

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.

002BA057 KN

Your right hand should grip the rear
handle. This also applies to left-handers.

8

HL 45

English / USA

!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.

!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.

9HL 45

English / USA

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!

On units with an adjustable cutter bar: To
reduce the risk of injury, never touch the
blades while making adjustments.

The power tool

15m (50ft)

falling objects or inadvertent contact with
the moving cutter blades of your power
tool always keep bystanders at least 50
feet (15m) away when the power tool is
running.

Stop the engine and cutting tool
immediately if you are approached.

has a large range.
In order to reduce
the risk of personal
or even fatal injury
to bystanders from

!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.

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.

10

HL 45

English / USA

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.

!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.

Catalytic converter

!Warning!

Some STIHL power tools
are equipped with a
catalytic converter, which
is designed to reduce the
exhaust emissions of the

engine by a chemical
process in the muffler. Due to this
process, the muffler does not cool down
as rapidly as conventional mufflers when
the engine returns to idle or is shut off.
To reduce the risk of fire and burn
injuries, the following specific safety
precautions must be observed.

!Warning!

Since a muffler with a catalytic converter
cools down less rapidly than conven­tional mufflers, always set your power
tool down in the upright position and
never locate it where the muffler is near
dry brush, grass, wood chips or other
combustible materials while it is still hot.

!Warning!

An improperly mounted or damaged
cylinder housing or a damaged/
deformed muffler shell may interfere
with the cooling process of the catalytic
converter. To reduce the risk of fire or
burn injury, do not continue work with a
damaged or improperly mounted
cylinder housing or a damaged/
deformed muffler shell.

Your catalytic converter is furnished with
screens designed to reduce the risk of
fire from the emission of hot particles.
Due to the heat from the catalytic
reaction, these screens will normally
stay clean and need no service or
maintenance. If you experience loss of
performance and you suspect a clogged
screen, have your muffler maintained by
a STIHL servicing dealer.

11HL 45

English / USA

Applications

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.

Do not use the hedge cutter in
residential areas during rest periods.

Preparations

Use lopping shears to cut out thick
branches first.

The use of a harness* makes handling
much easier.

Cutting sequence

If a radical cut is necessary, cut a little at
a time in several passes.

Do not throw cuttings in the rubbish
bin (garbage can) - they can be
composted!

389BA008 KN

Vertical cut

Swing the hedge cutter up and down in
an arc as you move along the hedge ­use both sides of cutting blades.

Long reach without additional aids.

Working with the hedge cutter in an
overhead position is tiring. Take frequent
breaks to reduce risk of injury.

12

* see “Guide to Using this Manual”

HL 45

Assembling the Unit

2

English / USA

Horizontal cut

Hold cutting blades at an angle of
0° to 10° as you swing the hedge cutter
horizontally.

Cutting without standing directly in front
of the hedge, e.g. with flowerbed or ditch
between operator and hedge.

Swing the hedge cutter in an arc towards
the outside of the hedge so that the
cuttings fall to the ground.

5

7

3

4

389BA010 KN

Mounting the loop handle

: Fit the clamp (1) in the loop

handle (2) and place them both
on the drive tube (3).

: Place clamp (4) in positon and

line up the holes.

: Insert the screws (5).
: Fit the square nuts (6). Tighten the

screws moderately.

: Line up the loop handle.
: Tighten down the screws firmly.

1

3

2

1

1

6

405BA001 KN

Mounting the gearbox

: Loosen the clamp screws (1).
: Push the gearbox (2) onto the drive

tube (3) - turn the gearbox back and
forth as necessary until the end of
the drive tube (3) is beyond the slot
in the clamp (see arrow). Push
gearbox fully home as far as stop.

: Line up the gearbox on the drive

tube so that the machine support on
the powerhead points down and the
cutting blades are horizontal.

: Tighten down the clamp screws

firmly.

405BA002 KN

13HL 45

English / USA

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 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
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.

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

US gal. US fl.oz

12.6
2 1/2 6.4

512.8

Dispose of empty mixing-oil canisters
only at authorized disposal locations.

Oil (STIHL 50:1 or
equivalent high-quality oils)

14

HL 45

English / USA

Fueling

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.

Starting / Stopping

1

232BA046 KN

4

Starting

: Move stop switch (1) to position I
: Hold down the throttle trigger

interlock (2) and squeeze the
throttle trigger (3) until catch (4) can
be engaged in the notch (arrow).

: Release the throttle trigger, catch

and throttle trigger interlock in that
order. This is the starting throttle

position.

2

6

5

3

405BA003 KN

Set the choke lever (5):

For cold start to g
For warm start to e

: Press fuel pump bulb (6) at least five

times.

405BA010 KN

15HL 45

English / USA

: Put the unit on the ground: It must

rest securely on the engine support
and the gearbox.

: Remove the blade guard.
: Check that cutting blades are not

touching the ground or any other
obstacles.

: Make sure you have a firm footing:

Hold the unit firmly on the ground
with your left hand. Your thumb
should be under the housing.

Do not stand or kneel on the drive
tube!

: Pull the starter grip 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 break.

: Do not let the starter grip snap back.

Guide it slowly back into the housing

405BA004 KN

so that it can rewind properly.

5

If the engine is cold:

(choke position g)

: Pull the starter rope five times.
: Move the choke lever (5) to e
: Continue cranking until engine runs.

Note: If the engine does not start
after 10 pulls with the choke lever
set to e :
Set choke to g , pull the starter
rope five times, move choke to e
and continue cranking.

If engine is warm:

: Continue cranking until engine runs

(choke lever to e )

As soon as engine runs

: Squeeze the throttle trigger to

disengage the tongue, then release
the trigger – the engine settles down
to idle speed.

405TI011 KN

If the engine stops during warm-up or
acceleration:

: Repeat starting procedure as

described under “If engine is cold”

Make sure the carburetor is
correctly adjusted - cutting blades
must not run when engine is idling.

Your unit is now ready for operation.

16

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English / USA

Cleaning the Air Filter

To stop the engine:

: Move switch to position O

Additional hints on starting

- If the engine does not start:

: Make sure all settings are correct

(choke shutter, throttle trigger
in starting throttle position, stop
switch to I)

: Repeat the starting procedure

7

- If the engine still does not start:

: Move switch to O
: Pull off the spark plug boot (7).
: Unscrew and dry off the spark plug.
: Open throttle wide.
: Crank the engine several times with

the starter to clear the combustion
chamber.

: Refit the spark plug and connect the

spark plug boot - push it down firmly.

: Move switch to I
: Set choke lever to e -

even if the engine is cold.

: Now start the engine.

6

Fuel tank run until dry and then
refueled

: Press the fuel pump bulb (6) at least

405BA012 KN

five times - even if bulb is filled with
fuel.

: Now start the engine.

2

1

405BA014 KN

232BA017 KN

Dirty air filters reduce engine power
increase fuel consumption and make
starting more difficult.

If there is a noticeable loss of engine
power

: Set choke lever to g
: Press in the tab (1) and swing the

filter cover (2) open.

: Clean away loose dirt from around

the filter.

17HL 45

English / USA

Motor Management Adjusting the Carburetor

4

3

: Remove the felt filter element (3).
: Do not wash the felt element. Fit a

new one. As a temporary measure,
clean it by knocking it out on the
palm of your hand or blowing it out
with compressed air.

Replace damaged parts of filter.

: Place the felt element (3) in the filter

housing (4).

: Close the filter cover so that it snaps

into position.

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.

232BA018 KN

General Information

L

H

1

3/4

LA

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.

253BA000 KN

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English / USA

Standard Setting

: Shut off the engine.
: Inspect cutting blades and clean if

necessary (clean, move freely, not
warped).

: Check the air filter and clean or

replace if necessary.

: Turn high speed screw (H)

counterclockwise (max.
far as stop.

: Carefully screw the low speed

screw (L) down onto its seat. Then
open it one turn counterclockwise

: Start and warm up the engine.
: Adjust idle speed with the idle speed

screw (LA) so that the cutting
blades do not run.

3

/4 turn) as

Adjusting Idle Speed

Engine stops while idling

: Low speed screw (L) must be one

turn open.

: Turn idle speed screw (LA) slowly

clockwise until the engine runs
smoothly – cutting blades must not
run.

Cutting blades run when engine
is idling

: Turn idle speed screw (LA) slowly

counterclockwise until cutting
blades stop running and then turn
the screw about another
in the same direction.

Erratic idling behavior, poor
acceleration

(although low speed screw is one turn
open)

Idle setting too lean:

: Turn low speed screw (L)

counterclockwise until the engine
runs and accelerates smoothly.

It is usually necessary to change the
setting of the idle speed screw (LA)
after every correction to the low speed
screw (L).

1

/2 to 1 turn

Fine Tuning for Operation at High
Altitude or at Sea Level

L

H

1

3/4

LA

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.

At high altitudes

: Turn the high speed screw (H)

clockwise (leaner) no further than
stop.

At sea level

: Turn the high speed screw (H)

counterclockwise (richer) no further
than stop.

253BA000 KN

19HL 45

English / USA

Catalytic Converter* Checking the Spark Plug

Units with a catalytic converter* may
only be operated with unleaded

gasoline and STIHL two cycle engine
oil or equivalent quality two cycle engine

oils in a mix ratio of 50:1 (see chapter
“Fuel”).

The catalylic converter in the muffler
reduces noxious emissions in the
exhaust gas.

Correct adjustment of the carburetor (if
adjustable) and observance of the
specified mix ratio of gasoline and two
cycle engine oil are essential to
minimize harmful exhaust emissions
and ensure a long catalyst service life.

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.

* see “Guide to Using this Manual”

20

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