Stihl BR 450 Instruction Manual

STIHL BR 450, 450 C

WARNING

Read Instruction Manual thoroughly
before use and follow all safety
precautions – improper use can
cause serious or fatal injury.

ADVERTENCIA

Antes de usar la máquina lea y siga
todas las precauciones de
seguridad dadas en el manual de
instrucciones – el uso incorrecto
puede causar lesiones graves o
mortales.

Instruction Manual
Manual de instrucciones

Instruction Manual
1 - 36

Manual de instrucciones
37 - 78

Contents

English

Guide to Using this Manual 2
Safety Precautions and Working

Techniques 3
Assembling the Unit 12
Adjusting the Throttle Cable 14
Fitting the Harness 15
Fuel 15
Fueling 16

Original Instruction ManualPrinted on chlorine-free paper

Information Before You Start 18
Starting / Stopping the Engine 18
Operating Instructions 21
Replacing the Air Filter 21
Adjusting the Carburetor 22
Spark Plug 23
Spark Arresting Screen in Muffler 24
Storing the Machine 25
Inspections and Maintenance by

Dealer 25
Maintenance and Care 26
Main Parts 28
Specifications 29
Maintenance and Repairs 30

Printing inks contain vegetable oils, paper can be recycled.

Disposal 30
Limited Warranty 31
STIHL Incorporated Federal

Emission Control Warranty
Statement 31

STIHL Incorporated California
Exhaust and Evaporative
Emissions Control Warranty
Statement 33

Trademarks 35

Allow only persons who fully understand
this manual to operate your blower.

To receive maximum performance and
satisfaction from your STIHL blower, 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
blower. For further information you can
go to www.stihlusa.com.

Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.

WARNING

Because a blower is a high-speed tool,
some special safety precautions must
be observed as with any other power
tool to reduce the risk of personal injury.
Careless or improper use may cause
serious or even fatal injury.

© ANDREAS STIHL AG & Co. KG, 2022

0458-391-8621-A. VA9.C22.

0000007092_016_GB

BR 450, BR 450 C

This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.

1

English

Guide to Using this Manual

Pictograms

The meanings of the pictograms
attached to or embossed on the
machine are explained in this manual.

Depending on the model concerned, the
following pictograms may be on your
machine.

Fuel tank for gasoline
and engine oil mixture

Air intake winter mode

Air intake summer mode

Press to operate manual
fuel pump

Symbols in Text

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

N Remove the screw (1)
N Pull the spark arresting screen (2)

upwards out of the muffler

In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are indicated with the
symbols and signal words described
below:

DANGER

Indicates a hazardous situation that, if
not avoided, will result in death or
serious injury.

WARNING

Indicates a hazardous situation that, if
not avoided, could result in death or
serious injury.

NOTICE

Indicates a risk of property damage,
including damage to the machine or its
individual components.

described in this manual, please contact
your STIHL dealer or the STIHL
distributor for your area for assistance.

Many operating and safety instructions
are supported by illustrations.

The individual steps or procedures
described in the manual may be shown
in different ways:

N A bullet indicates a step or

procedure.

2

Engineering Improvements

STIHL’s philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time to time. Therefore,
some changes, modifications and
improvements may not be covered in
this manual. If the operating
characteristics or the appearance of
your machine differs from those

BR 450, BR 450 C

English

Safety Precautions and
Working Techniques

Because a blower is gas­oline-powered and
produces a strong air
blast, 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.

Use your blower only for clearing leaves,
grass, paper and dust in yards, gardens,
sport stadiums, parks, driveways and
parking lots.

WARNING

Do not use it for other purposes, since
misuse may result in personal injury or
property damage, including damage to
the machine.

WARNING

Minors should never be allowed to use
this power tool. Bystanders, especially
children, and animals should not be
allowed in the area where it is in use.

WARNING

To reduce the risk of injury to bystanders
and damage to property, never let your
power tool run unattended. When it is
not in use (e.g. during a work break),
shut it off and make sure that
unauthorized persons do not use it.

Most of these safety precautions and
warnings apply to the use of all STIHL
blowers. 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.

Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.

Safe use of a blower involves

1. the operator

2. the power tool

3. the use of the power tool.

THE OPERATOR

Physical Condition
You must be in good physical condition

and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.

WARNING

Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition that
might be aggravated by strenuous work,
check with your doctor before operating
this machine.

WARNING

Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce white finger
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 white
finger 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

BR 450, BR 450 C

3

English

factors in the development of white
finger disease. In order to reduce the
risk of white finger 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.

– 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 handle with
constant, excessive pressure. Take
frequent breaks.

All the above-mentioned precautions do
not guarantee that you will not sustain
white finger 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 Z87 "+" (or your
applicable national
standard).

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.

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 drawn into
the air intake. 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.

WARNING

To reduce the risk of injury when the
inhalation of dust cannot be
substantially controlled use an
appropriate respirator for the material
being blown. For more information see
the "Working conditions" section of
these Safety Precautions.

THE POWER TOOL

For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts."

WARNING

Never modify this power tool in any way.
Only attachments supplied by STIHL 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.

4

BR 450, BR 450 C

English

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.

WARNING

Small particles (e.g. dust) blown through
the blower tubes and nozzle can cause
a static charging of the blower tubes.
This is especially true in low humidity
and high dust conditions. In order to
reduce the risk of shock from static
charging and subsequent injury from
loss of control, your blower has features
designed to help reduce the build up of
static electricity in the blower tubes and
equalize the charge with the engine
and/or operator:

The control handle is designed to
conduct static electricity through the
throttle cable to the engine and from the
handle through the operator to the
ground.

If your blower is properly assembled and
you are still experiencing static shocks,
make sure that your footwear has
conductive soles and try operating your
unit without gloves, which may be
interfering with the conduction of the
charge.

THE USE OF THE POWER TOOL

Transporting the Power Tool

WARNING

Always switch off the engine before
taking the machine off your back and
putting it down. When transporting it in a
vehicle, properly secure it to prevent
turnover, fuel spillage and damage to
the unit.

Fuel
Your STIHL power tool uses an oil-

gasoline mixture for fuel (see the "Fuel"
chapter in this 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

To reduce the risk of fire and serious
personal injury, always remove the
backpack blower from the operator’s
back and place it on the ground before
attempting to fuel the machine.

WARNING

Pick a Safe Location
To reduce the risk of fire and explosion,

fuel your power tool in a well-ventillated
area, outdoors away from flames, pilot
lights, heaters, electric motors, and
other sources of ignition. Vapors can be
ignited by a spark or flame many feet
away. 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 power tool. Take care not to get fuel
on your clothing. If this happens, change
your clothing immediately.

Allow the Power Tool to Cool Before
Removing the Fuel Cap

WARNING

Gasoline vapor pressure may build up
inside the fuel tank. The amount of
pressure depends on a number of
factors such as the fuel used, altitude
and temperature. To reduce the risk of
burns and other personal injury from

BR 450, BR 450 C

5

English

escaping gas, vapor and fumes, always
shut off the engine and allow it to cool
before removing the fuel cap.

The engine is air cooled. When it is shut
off, cooling air is no longer drawn across
the cylinder and engine temperatures
will rise for several minutes before
starting to cool. In hot environments,
cooling will take longer. To reduce the
risk of burns and other personal injury
from escaping gas, vapor and fumes,
allow the power tool to cool. If you need
to refuel before completing a job, turn off
the machine and allow the engine to cool
before opening the fuel tank.

Fuel Spraying or “Geysering”

WARNING

Removing the cap on a pressurized fuel
tank can result in gasoline, vapors and
fumes being forcefully sprayed out from
the fuel tank in all directions. The
escaping gasoline, vapors or fumes can
cause serious personal injury, including
fire and burn injury, or property damage.

Sometimes also referred to as "fuel
geysering," fuel spraying is an expulsion
of fuel, vapors and fumes which can
occur in hot conditions, or when the
engine is hot, and the tank is opened
without allowing the power tool to cool
adequately. It is more likely to occur
when the fuel tank is half full or more.

Pressure is caused by fuel and heat and
can occur even if the engine has not
been running. When gasoline in the fuel
tank is heated (by ambient
temperatures, heat from the engine, or
other sources), vapor pressure will
increase inside the fuel tank.

Some blends of gasoline, particularly
those designed for use in winter, are
more volatile and may cause tanks to
pressurize more quickly or create
greater pressure. At higher altitudes,
fuel tank pressurization is more likely.

How to Avoid Fuel Spraying
Removing the fuel cap on a pressurized

tank can result in gasoline, vapors and
fumes being forcefully sprayed out from
the fuel tank in all directions. To reduce
the risk of burns, serious injuries or
property damage from fuel spraying:

– Follow the fueling instructions in this

chapter.

– Always assume your fuel tank is

pressurized.

– Allow the power tool to cool before

removing the fuel cap.

– In hot environments, cooling will

take longer.

– The engine is air cooled. When it is

shut off, cooling air is no longer
drawn across the cylinder and the
engine temperature will rise for
several minutes before starting to
cool.

After the power tool has cooled
appropriately, follow the safety
instructions in this chapter for removing
the cap.

Never remove the fuel filler cap by
turning it directly to the open position.
First check for residual pressure in the
tank by slowly turning the cap
approximately 1/2 turn counter­clockwise. The cap should be held in
place by the threads while allowing
residual vapor/pressure to be relieved.

Once the fumes or vapor have been
relieved, turn the cap further until it can
be removed from the tank opening.

Use only good quality fuel that is
appropriate for the season (summer v.
winter blends). Some blends of
gasoline, particularly winter blends, are
more volatile and can contribute to fuel
spraying.

Removing the Threaded Fuel Filler Cap

WARNING

After allowing the power tool to cool,
remove the fuel filler cap slowly and
carefully to allow any remaining
pressure build-up in the tank to release:

– While maintaining steady,

downward pressure, slowly turn the
cap approximately 1/2 turn counter­clockwise.

– If any significant venting occurs,

immediately re-seal the tank by
turning the cap clockwise to the
closed position. Allow the power
tool to cool further before
attempting to open the tank.

– Turn the cap to the open position

only after the contents of the tank
are no longer under pressure.

– Never remove the cap by turning it

directly to the open position. First
allow the power tool to cool
adequately and then release any
residual pressure by slowly turning it
approximately 1/2 turn counter­clockwise.

– Never attempt to remove the cap

while the engine is still hot or
running.

6

BR 450, BR 450 C

English

Installing the Threaded Fuel Filler Cap

WARNING

Unit vibrations can cause
an improperly tightened
fuel filler cap to loosen or
come off and spill quanti­ties of fuel. To reduce the
risk of fuel spillage and
fire, tighten the fuel filler
cap by hand with as

much force as possible.
Damaged or Broken Cap
If your fuel cap does not tighten properly,

it may be damaged or broken. Stop
using the power tool and take it to your
authorized STIHL dealer for repair.

Vapor Lock

WARNING

Vapor lock occurs when fuel in the fuel
line or carburetor vaporizes, causing
bubbles to block the free flow of liquid
fuel into the carburetor. Vapor lock
cannot be relieved or affected by
opening the fuel tank. Removing the fuel
filler cap without first allowing the power
tool to cool adequately can result in fuel
spraying. Always follow the instructions
in this section when removing the fuel
cap.

To relieve vapor lock:
– Press the manual fuel pump bulb at

least 20 to 30 times – even if the
bulb is already filled with fuel – to
clear the vapor and send liquid fuel
into the carburetor. Then start the
power tool. For specific starting
instructions, see the appropriate
section of your instruction manual.

– If the manual fuel pump bulb will not

be filled, place the Choke Knob to
the cold start position c and pull
the starter cord until the engine
runs. If the engine does not fire after
10 pulls in the cold start position c,
place the Choke Knob to the warm
start position o and start the
engine in the warm start position o.

– If your power tool will not restart, or

if vapor lock occurs again, the
power tool is being used in
conditions too extreme for the fuel
being used. Discontinue use and let
the engine cool completely before
attempting to start the power tool.

Before Operation

WARNING

Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, setting
lever and stop switch. The throttle trigger
must move freely and always spring
back to the idle position. Never attempt
to modify the controls or safety devices.

WARNING

Check fuel system for leaks, especially
the visible parts, e.g., filler cap, hose
connections, manual fuel pump (only for

power tools equipped with a manual fuel
pump). Do not start the engine if there
are leaks or damage – risk of fire. Have
the power tool repaired by a STIHL
servicing dealer before using it.

WARNING

Never operate your power tool if it is
damaged, improperly adjusted or
maintained, or not completely and
securely assembled.

WARNING

Check that the spark plug boot is
securely mounted on the spark plug – a
loose boot may cause arcing that could
ignite combustible fumes and cause a
fire.

Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, fuel mix,
grease or resin in order for you to
maintain a firm grip and properly control
your power tool.

WARNING

To reduce the risk of injury from parts
thrown by the fan wheel, check the fan
housing for damage (cracks or holes
that could allow foreign objects to
contact the fan wheel). If any such
damage is found, stop using the unit and
contact your STIHL dealer for repair.

WARNING

Adjust carrying harness to suit your size
before starting work.

In an emergency, you may slip out of the
harness and throw off the machine
quickly. Try slipping out of the harness a

BR 450, BR 450 C

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English

0009BA001 KN

number of times before using the
machine in order to become
accustomed to it. Do not throw off the
machine while practicing as it could
result in damage to the machine.

For specific starting instructions, see the
appropriate section of your instruction
manual.

Starting
To reduce the risk of fire and burn

injuries, start the engine at least 10 feet
(3 m) from the fueling spot, outdoors
only.

WARNING

Your power tool is a one-person
machine. To reduce the risk of eye or
other injury from thrown objects, insure
that bystanders are at least 50 feet
(15 m) away during use. Stop operation
immediately if you are approached.

WARNING

This unit is equipped with an ignition
system that is normally in operational
readiness. After the setting lever is used
to stop the engine, it automatically
springs back to the "on" position. If the
engine is warm, it may be possible to
start it by simply pulling the starter rope,
with no further adjustments. To reduce
the risk of injury, be particularly alert to
keep children away from the unit.

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

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.

Once the engine has started,
immediately blip the throttle trigger,
which should cause the choke knob to
move to the run position and allow the
engine to slow down to idle.

During Operation
Holding and Controlling the Power Tool

The blower is designed for single­handed operation with the right hand on
the control handle. It should be carried
as a backpack with the straps of the
harness over both shoulders.

Watch out for small animals when using
the blower on open ground, in yards and
gardens.

WARNING

To reduce the risk of loss of control,
never carry the unit with the strap(s)
over one shoulder.

Wrap your fingers tightly around the
handle, keeping the control handle
cradled between your thumb and
forefinger. Keep your hand in this
position to have your machine under
control at all times.

WARNING

Special care must be taken in slippery
conditions (wet ground) and in difficult,
overgrown terrain. Watch for hidden
obstacles such as tree stumps, roots,
rocks, holes 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.

To reduce the risk of stumbling and loss
of control, do not walk backward while
operating the machine.

WARNING

To reduce the risk of injury from loss of
control, never work on a ladder or on any
other insecure support.

Working Conditions
To minimize blowing time, use a rake

and broom to loosen dirt particles before
you start blowing.

8

BR 450, BR 450 C

English

Save water by using a blower instead of
a water hose for lawn and garden work
wherever possible, e.g. for cleaning
yards and patios.

Recommended working technique to
minimize air pollution:

– If conditions are very dusty, dampen

surfaces slightly before blowing.

– Pull out the nozzle to full length so

that the airstream is at ground level.

– Do not blow particles in the direction

of bystanders, in particular in the
direction of children, pets, open
windows or freshly washed
vehicles. Take special care in such
situations.

– Remove the blow-swept debris in

rubbish bins – do not blow it onto the
neighbor's land.

Recommended working technique to
minimize noise:

– Operate your power tool at

reasonable times only – not early in
the morning, late at night or during
midday rest periods when people
could be disturbed. Observe local
rest periods.

– Fewer engines mean less noise.

Where possible, do not run more
than one power tool at any time.

– Operate blowers at the lowest

engine speed necessary to
accomplish the task.

– Check your blower before starting

work. Pay special attention to the
muffler, air intakes and air filter.

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. If exhaust
fumes become concen­trated due to insufficient
ventilation, clear obstruc­tions from work area to
permit proper ventilation
before proceeding and/or
take frequent breaks to
allow fumes to dissipate
before they become
concentrated.

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. This includes wood dust,
especially from hardwoods, but also
from some softwoods such as Western
Red Cedar. 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.

WARNING

If the substance being blown is a
commercial substance, review the
material safety data sheet for that
substance and / or consult the material
manufacturer / supplier. The state of
California and some other authorities,
for instance, have published lists of
substances known to cause cancer,
reproductive toxicity, etc.

WARNING

Breathing asbestos dust is dangerous
and can cause severe or fatal injury,
respiratory illness or cancer. The use
and disposal of asbestos-containing

BR 450, BR 450 C

9

English

products have been strictly regulated by
OSHA and the Environmental Protection
Agency. If you have any reason to
believe that you might be blowing or
otherwise disturbing asbestos,
immediately contact your employer or a
local OSHA representative.

WARNING

Dust with silica in its composition may
contain crystalline silica. Silica is a basic
component of sand, quartz, brick, clay,
granite and numerous other minerals
and rocks, including masonry and
concrete products. Repeated and / or
substantial inhalation of airborne
crystalline silica can cause serious or
fatal respiratory disease, including
silicosis. In addition, the state of
California and some other authorities
have listed respirable crystalline silica as
a substance known to cause cancer.
When encountering such materials,
always follow the respiratory
precautions mentioned above.

Operating Instructions

WARNING

In the event of an emergency, switch off
the engine immediately – move the
setting lever to 0 or STOP.

WARNING

Even though bystanders should be kept
away from the running power tool, never
work alone. Keep within calling distance
of others in case help is needed.

Stop the engine immediately if you are
approached.

WARNING

To reduce the risk of personal injury, do
not direct air blast towards bystanders,
since the high pressure of the air flow
can injure eyes and can blow small
objects at great speed.

WARNING

The blower fan between the air intake
and output openings rotates whenever
the engine is running.

Never insert any foreign object into the
air intake of the machine or into the
nozzle of the blower. It will damage the
fan wheel and may cause serious injury
to the operator or bystanders as a result
of the object or broken parts being
thrown out at high speed.

Do not place the blower on the ground
when operating at high speed, because
small objects such as sand, grass, dust,
etc. may be pulled into the air intake and
damage the fan wheel. It is best to turn
the machine off when putting it on the
ground.

WARNING

Never modify your muffler. Any
modification could cause an increase in
heat radiation, sparks or sound level,
thereby increasing the risk of fire, burn
injury or hearing loss. You may also
permanently damage the engine. Have
your muffler serviced and repaired by
your STIHL servicing dealer only.

WARNING

The muffler and other parts of the engine
(e.g. fins of the cylinder, spark plug)
become hot during operation and remain
hot for a while after stopping the engine.
To reduce risk of burns, do not touch the
muffler and other parts while they are
hot. Keep the area around the muffler
clean. Remove excess lubricant and all
debris such as pine needles, branches
or leaves. Let the engine cool down
sitting on concrete, metal, bare ground
or solid wood away from any
combustible substances.

WARNING

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

Your muffler is furnished with a spark
arresting screen designed to reduce the
risk of fire from the emission of hot
particles. Never operate your unit with a
missing or damaged spark arresting
screen. If your gas/oil mix ratio is correct
(i.e., not too rich), this screen will
normally stay clean as a result of the
heat from the muffler and need no
service or maintenance. If you
experience loss of performance and you
suspect a clogged screen, have your
muffler maintained by a STIHL servicing
dealer. Some state or federal laws or
regulations may require a properly
maintained spark arrestor for certain

10

BR 450, BR 450 C

English

uses. See the "Maintenance, Repair and
Storing" section of these Safety
Precautions. Remember that the risk of
a brush or forest fire is greater in hot or
dry conditions.

WARNING

Some STIHL power tools

are equipped with a cata-

lytic converter, which is

designed to reduce the

exhaust emissions of the

engine by a chemical pro-

cess in the muffler. Due

to this process, the muf-

fler does not cool down

as rapidly as conven-

tional mufflers when the

engine returns to idle or

is shut off. To reduce the

risk of fire and burn inju-

ries when using a

catalytic converter,

always set your power

tool down in the upright

position and never locate

it where the muffler is

near dry brush, grass,

wood chips or other com-

bustible materials while it

is still hot.

MAINTENANCE, REPAIR AND
STORAGE

WARNING

Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.

Strictly follow the maintenance and
repair instructions in the appropriate
section in this instruction manual.
Please refer to the maintenance chart in
this instruction manual.

WARNING

Always stop the engine and make sure
that the fan is stopped before doing any
maintenance or repair work or cleaning
the power tool. Do not attempt any
maintenance or repair work not
described in this instruction manual.
Have such work performed by your
STIHL servicing dealer only.

Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.

WARNING

Use the specified spark plug and make
sure it and the ignition lead are always
clean and in good condition. Always
press spark plug boot snugly onto spark
plug terminal of the proper size. A loose
connection between spark plug terminal
and the ignition wire connector in the
boot may create arcing that could ignite
combustible fumes and cause a fire.
Keep spark plug clean, and make sure
ignition lead is in good condition. Do not
use a spark plug with a detachable SAE
adapter terminal. Arcing may occur that
could ignite combustible fumes and
cause a fire. This can result in serious
injuries or damage to property.

WARNING

Never test the ignition system with the
boot removed from the spark plug or
with a removed spark plug, since
uncontained sparking may cause a fire.

WARNING

Do not operate your power tool if the
muffler is damaged, missing or modified.
An improperly maintained muffler will
increase the risk of fire and hearing loss.
Your muffler is equipped with a spark­arresting screen to reduce the risk of
fire; never operate your power tool if the
screen is missing, damaged or clogged.
Remember that the risk of a brush or
forest fire is greater in hot or dry
weather.

In California, it is a violation of § 4442 or

§ 4443 of the Public Resources Code to
use or operate gasoline-powered tools
on forest-covered, brush-covered or
grass-covered land unless the engine’s
exhaust system is equipped with a
complying spark arrester that is
maintained in effective working order.
The owner/operator of this product is
responsible for properly maintaining the
spark arrester. Other states or
governmental entities/agencies, such as
the U.S. Forest Service, may have
similar requirements. Contact your local
fire agency or forest service for the laws
or regulations relating to fire protection
requirements.

Tighten all nuts, bolts and screws except
the carburetor adjustment screws after
each use.

BR 450, BR 450 C

11

English

1

0416BA001 KN

2

3

2

1

4

0416BA002 KN

3

0416BA003 KN

5

6

2

5

6

2

0416BA004 KN

7

For maintenance items please also refer
to the maintenance chart in this
instruction manual.

Store the power tool in a dry and high or
locked location out of reach of children.

Before storing for longer than a few
days, always empty the fuel tank. See
chapter "Storing the machine" in this
instruction manual.

Store fuel in an approved and properly
labeled safety-type canister only. Take
care when handling gasoline! For health
and safety reasons, avoid direct contact
with the skin and avoid inhaling fuel
vapor!

Assembling the Unit

Mounting the Hose Clamps and Pleated
Hose

N Push the hose clamp (5) (without

retainer for throttle cable) onto the
blower tube (6) – the positioning
marks must face to the right.

N Push the blower tube (6) into the

pleated hose (2).

N Push the hose clamp (1) (with

retainer for throttle cable) onto the
elbow (3) – the positioning marks
must face to the left.

N Push the pleated hose (2) over the

elbow (3).

N Push the hose clamp (5) onto the

pleated hose (2).

N Line up the hose clamp (5) and

blower tube (6) – as shown.

N Secure the hose clamp (5) with the

screw (7).

N Push the hose clamp (1) onto the

pleated hose (2).

N Line up the positioning marks on the

hose clamp (1) and elbow (3) – the
screw lug faces down.

N Secure the hose clamp (1) with the

screw (4).

12

BR 450, BR 450 C

English

4

6

5

0416BA008 KN

0416BA007 A1

1

2

3

3

0416BA005 KN

1

2

1

3

0416BA006 KN

2

Mounting the Control Handle

3

1

2

N Push the control handle (1) onto the

mount (2) .

N Insert and tighten down the

screws (3) firmly.

N Engage the throttle cable (4) with

sleeve (5) in the hose clamp (6).

Adjusting the Control Handle

0000-GXX-2045-A1

N Open the clamping lever (3).
N Move the control handle (1) along

the blower tube (2) to the most
comfortable position.

N Close the clamping lever (3).

Mounting the Nozzle (BR 700)

N Push the nozzle (1) onto the blower

tube (2) and engage it on the
lugs (3).

Removing the nozzle (BR 700)

N Rotate the nozzle (1) in the direction

of the arrow until the lugs (3) are
covered.

N Pull the nozzle (1) off the blower

tube (2).

Mounting the Nozzle (BR 700 X)

3

1

2

0000-GXX-3989-A0

N Push the nozzle (1) onto the blower

tube (2) and engage it on the
lugs (3).

N Rotate the nozzle (1) in the direction

of arrow as far as the stop.

BR 450, BR 450 C

13

English

0416BA009 KN

002BA655 KN

Removing the nozzle (BR 700 X)

2

1

N Rotate the nozzle (1) in the direction

of arrow as far as the stop.

N Pull the nozzle (1) off the blower

tube (2).

Adjusting the Blower Tube (BR 700)

1

N Loosen the union nut (1).
N Pull the blower tube (2) out to the

required length.

N Tighten the union nut (1).

2

Wear Mark on Nozzle

0000-GXX-3990-A0

The front end of the nozzle wears away
due to abrasive ground contact during
operation. The nozzle is subject to
normal wear and tear and must be
replaced when the wear mark is
reached.

Transport Aid

When storing or transporting the
machine:

0416BA015 KN

N Secure the blower tube to the

handle on the backplate with the
hook and loop fastener.

Adjusting the Throttle Cable

It may be necessary to correct the
adjustment of the throttle cable after
assembling the machine or after a
prolonged period of operation.

Adjust the throttle cable only when the
unit is completely and properly
assembled.

N Set the throttle trigger to the full

throttle position.

N Carefully rotate the screw in the

throttle trigger in the direction of the
arrow until you feel initial resistance.
Then rotate it another half turn in the
same direction.

14

BR 450, BR 450 C

English

373BA003 KN

373BA004 KN

Fitting the Harness

Adjusting the Harness

N Pull the straps downwards to tighten

the harness

Loosening the Harness

N Lift the tabs of the two sliding

adjusters.

N Adjust the harness so that the

backplate fits snugly and securely
against your back

Fuel

This engine is certified to operate on
unleaded gasoline and the STIHL two­stroke engine oil at a mix ratio of 50:1.

Your engine requires a mixture of high­quality gasoline and two-stroke air
cooled engine oil.

Use mid-grade unleaded gasoline with a
minimum octane rating of 89 ((R+M)/2)
and no more than 10% ethanol content.

NOTICE

Fuel with an octane rating below 89 may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.

The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or damage the
engine. For this reason STIHL
recommends that you use only quality
unleaded gasoline!

NOTICE

Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
and should not be used.

For further details, see
www.STIHLusa.com/ethanol
The ethanol content in gasoline affects

engine speed – it may be necessary to
readjust the carburetor if you use fuels
with various ethanol contents.

WARNING

To reduce the risk of personal injury
from loss of control and/or contact with
the running cutting tool, do not use your
unit with an incorrect idle adjustment. At
correct idle speed, the cutting tool
should not move.

If your machine’s idle speed is
incorrectly adjusted, have your
authorized STIHL servicing dealer
check your machine and make the
proper adjustments and repairs.

The idle speed and maximum speed of
the engine change if you switch from a
fuel with a certain ethanol content to a
fuel with a much higher or lower ethanol
content.

This problem can be avoided by always
using fuel with the same ethanol
content.

To ensure the maximum performance of
your STIHL engine, use a high quality 2­cycle engine oil. To help your engine run
cleaner and reduce harmful carbon
deposits, STIHL recommends using
STIHL HP Ultra 2-cycle engine oil or ask
your dealer for an equivalent fully
synthetic 2-cycle engine oil.

To meet the requirements of EPA and
CARB we recommend to use STIHL HP
Ultra oil.

STIHL MotoMix

STIHL recommends the use of STIHL
MotoMix. STIHL MotoMix has a high
octane rating and ensures that you
always use the right gasoline/oil mix
ratio.

BR 450, BR 450 C

15

English

STIHL MotoMix uses STIHL HP Ultra
two-stroke engine oil suited for high
performance engines.

For further details, see
www.STIHLusa.com/ethanol
If not using MotoMix, use only STIHL

two-stroke engine oil or equivalent high­quality two-stroke engine oils that are
designed for use in air cooled two-cycle
engines.

The use of non-seasonal gasoline
blends may increase the potential for
pressure to build in the fuel tank during
operation. For example, using a winter
blend during the summer will increase
pressure in the fuel tank. Always use
gasoline blends appropriate to the
season, altitude and other
environmental factors.

Do not use NMMA or TCW rated (two­stroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chain saws, mopeds, etc.).

WARNING

Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the container
from your vehicle and place the
container on the ground before filling. To
reduce the risk of sparks from static
discharge and resulting fire and/or
explosion, do not fill fuel containers that
are sitting in or on a vehicle or trailer.

The container should be kept tightly
closed in order to limit the amount of
moisture that gets into the mixture.

The machine's fuel tank should be
cleaned as necessary.

Fuel mix ages

If not using MotoMix, only mix sufficient
fuel for a few days of work, not to exceed
30 days of storage. Store in approved
fuel-containers only. When mixing, pour
oil into the container first, and then add
gasoline. Close the container and shake
it by hand to ensure proper mix of oil and
gasoline.

WARNING

Shaking fuel can cause pressure to build
in the fuel container. To reduce the risk
of fire and severe personal injury or
property damage from fuel spraying,
allow the fuel container to sit for several
minutes before opening. Open the
container slowly to release any residual
pressures. Never open the fuel
container in the vicinity of any ignition
source. Read and follow all warnings
and instructions that accompany your
fuel container.

Gaso­line

US gal. US fl.oz.

12.6
2 1/2 6.4
5 12.8

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

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

Fueling

WARNING

Removing the cap on a pressurized fuel
tank can result in gasoline, vapors and
fumes being forcefully sprayed out from
the tank in all directions. The escaping
gasoline, vapors or fumes, sometimes
referred to as fuel spraying or
"geysering," can cause serious personal
injury, including fire and burn injury, or
property damage.

Fuel spraying can occur when the
engine is hot and the tank is opened
while under pressure. It can occur in hot
environments even if the engine has not
been running. Spraying is more likely to
occur when the fuel tank is half full or
more.

Avoid Injuries from Fuel Spraying.
Always follow the fueling instructions in

this manual:
– Treat every fuel tank as if it is

pressurized, particularly if it is half
full or more.

– Always allow the power tool to cool

adequately before attempting to
open the fuel tank or refueling; this
will take longer in hot conditions.

16

BR 450, BR 450 C

English

0002BA086 KN

002BA447 KN

002BA448 KN

– Never remove the cap by turning it

directly to the open position. Turn it
first approximately 1/2 of a turn
counter-clockwise to relieve any
residual pressure.

– Never open the fuel tank while the

engine is still hot or running.

– Never open the fuel tank or re-fuel

the power tool near any sparks,
flames or other ignition sources.

– Pick the right fuel: use only good

quality (89 octane or higher), fresh
fuel blended for the season.

– Vapor lock: do not remove the fuel

cap in an effort to relieve vapor lock.
Removing the cap has no effect on
vapor lock.

– Be aware that fuel spraying is more

likely at higher altitudes.

Preparations

N Before fueling, clean the filler cap

and the area around it to ensure that
no dirt falls into the tank.

N Position the machine so that the

filler cap is facing up.

WARNING

In order to reduce the risk of fire and
other personal injury from escaping gas
vapor and fumes, remove the fuel filler
cap slowly and carefully so as to allow
any pressure build-up in the tank to
release slowly.

Opening

WARNING

After allowing the power tool to cool,
remove the fuel filler cap slowly and
carefully to allow any remaining
pressure build-up in the tank to release:

N While maintaining steady,

downward pressure, slowly turn the
cap approximately a 1/2 turn
counter-clockwise.

N If any significant venting occurs,

immediately re-seal the tank by
turning the cap clockwise to the
closed position. Allow the power
tool to cool further before attempting
to open the tank.

N Turn the cap to the open position

only after the contents of the tank
are no longer under pressure.

N Remove the fuel filler cap.

WARNING

Never remove the cap by turning it
directly to the open position. First allow
the power tool to cool adequately and
then release any residual pressure by
slowly turning the cap approximately
1/2 turn counter-clockwise. Never
attempt to remove the cap while the
engine is still hot or running.

Refueling

Take care not to spill fuel while fueling
and do not overfill the tank – leave
approximately 1/2" (13 mm) air space.

Closing

WARNING

An improperly tightened fuel filler cap
can loosen or come off and spill
quantities of fuel. To reduce the risk of
fuel spillage and fire from an improperly
installed fuel cap, tighten the fuel filler
cap by hand with as much force as
possible:

BR 450, BR 450 C

17

English

0416BA013 KN

2

1

0416BA011 KN

0009BA012 KN

H

LA

L

N If your fuel cap still does not tighten

properly, it may be damaged or
broken. Stop using the power tool
and take it to your authorized STIHL
dealer for repair or replacement.

Information Before You Start

Positions of Master Control Lever

3

1

2

1 Setting lever
2 Throttle trigger
3 Starter switch (BR 450 C only)

Engine stop 0 – ignition interrupted,
engine stops. The setting lever does not
remain in ths position, it springs back.

Normal run position F – engine runs or is
ready to start. Throttle trigger can be
moved to any position.

Starting / Stopping the
Engine

Starting the Engine

N Observe safety precautions.

NOTICE

Start your unit on a clean, dust-free
surface only to ensure that no dust is
sucked in.

0014BA001 AS

N Move the setting lever to F

18

N Press the fuel pump bulb at least

eight times – even if the bulb is filled

Infinitely variable throttle setting –
throttle trigger can be locked in any
required position: Move setting lever (1)
upwards until required engine speed is
reached. To disengage, move the
setting lever back to the normal run
position F.

with fuel.

BR 450, BR 450 C

English

0009BA013 KN

0009BA014 KN

0009BA028 KN

0014BA005 AS

Cold engine (cold start)

N Push the choke knob in and turn it to

c.

Warm engine (warm start)

N Push the choke knob in and turn it to

o.

Also use this setting if the engine has
been running but is still cold.

Cranking

N Place the unit securely on the

ground and make sure that
bystanders are well clear of the
nozzle outlet.

N Make sure you have a firm footing:

Hold the unit with your left hand on
the housing and put one foot against
the base plate to prevent it slipping.

N 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 to full
length – it might otherwise break.

N Do not let the starter grip snap back.

Guide it slowly back into the housing
so that the starter rope can rewind
properly.

N Continue cranking until the engine

runs.

Electric start (BR 450 C)
The power tool is equipped with the

STIHL electric starter for convenient
starts.

The STIHL electric starter basically
consists of the following components:

– Rechargeable battery, integrated in

control unit

– Starter mechanism with starter

motor and starter gear
– Starter switch
The battery supplies the starter motor

with the power required to start the
engine.

The battery is recharged while the power
tool is running – the power tool is always
ready to start.

The starter battery is not replaceable – it
is integrated in the control unit.

If the power tool is stored at
temperatures below 0°C it may cool
down to a point where a start is inhibited
to protect the battery.

The engine must then be started
manually.

N Place the unit securely on the

ground and make sure that

bystanders and loose objects are

well clear of the nozzle outlet.

BR 450, BR 450 C

19

English

2

0416BA012 KN

0009BA017 KN

0416BA016 KN

N Make sure you have a firm footing:

Hold the unit with your left hand on
the carrying handle and grip the
control handle with your right hand.

Alternative:

N Place the unit securely on the

ground and make sure that
bystanders and loose objects are
well clear of the nozzle outlet.

12

N Slide the starter switch downwards.
N Press the starter switch

As soon as the engine runs

N Operate the throttle trigger (2).

N Choke knob automatically returns to

0014BA004 AS0014BA002 AS

the run position e when the throttle
trigger is operated.

At very low outside temperatures
N Open throttle slightly – warm up the

engine for a short period.

Stopping the Engine

N Move the setting lever to 0 – the

engine stops – the setting lever

springs back to the on position.

Other Hints on Starting

Electric starter does not operate
N Temperature below 0°C, electric

starter is deactivated - start engine

manually.
N Low electric starter battery - start

engine manually.
Engine stalls in cold start position c or

under acceleration
N Move the choke knob to o and

continue cranking until the engine

runs.
Engine does not start in warm start

position o
N Move the choke knob to c and

continue cranking until the engine

runs.
If the engine does not start

N Check that all settings are correct.
N Check that there is fuel in the tank

and refuel if necessary.

20

BR 450, BR 450 C

English

1

0002BA088 KN

1

2

N Check that the spark plug boot is

properly connected.

N Repeat the starting procedure.
Fuel tank run until completely dry
N After refueling, press the manual

fuel pump bulb at least five times –
even if the bulb is filled with fuel.

N Set the choke knob according to

engine temperature.

N Now start the engine.

Operating Instructions Replacing the Air Filter

During Operation

After a long period of full throttle
operation, allow the engine to run for a
short while at idle speed so that engine
heat can be dissipated by the flow of
cooling air. This helps protect engine­mounted components (ignition,
carburetor) from thermal overload.

After Finishing Work

Storing for a short period: Wait for the
engine to cool down. Keep the machine
in a dry place, well away from sources of
ignition, until you need it again. For
longer out-of-service periods – see
"Storing the Machine".

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

If there is a noticeable loss of engine
power

BR 450, BR 450 C

N Turn the choke knob to c .
N Loosen the screws (1).
N Remove the filter cover (2).

21

English

0002BA089 KN

3

0002BA082 KN

H

L

0002BA083 KN

LA

L

N Remove the filter element (3).
N Replace dirty or damaged filters.
N Fit the new filter in the filter housing.
N Fit the filter cover.
N Fit the screws and tighten them

down firmly.

Adjusting the Carburetor

General Information

The carburetor comes from the factory
with a standard setting.

This setting provides an optimum fuel-air
mixture under most operating
conditions.

Preparations

N Shut off the engine.
N Check the air filter and clean or

replace if necessary.

N Check that the throttle cable is

properly adjusted – readjust if
necessary – see chapter on
"Adjusting the Throttle Cable".

N Check the spark arresting screen

(not in all models, country-specific)
in the muffler and clean or replace if
necessary.

Standard Setting

N Turn high speed screw (H)

counterclockwise as far as stop (no

more than 3/4 turn).
N Turn the low speed screw (L)

clockwise as far as stop, then turn it

back 3/4 turn.

Adjusting Idle Speed

N Carry out the standard setting.
N Start and warm up the engine.

22

Engine stops while idling
N Turn the idle speed screw (LA)

slowly clockwise until the engine

runs smoothly.

BR 450, BR 450 C

English

2

0002BA049 KN

000BA039 KN

A

Erratic idling behavior, engine stops
even though setting of LA screw has
been corrected, poor acceleration

Idle setting is too lean
N Turn the low speed screw (L)

counterclockwise, no further than
stop, until the engine runs and
accelerates smoothly.

Erratic idling behavior
Idle setting is too rich
N Turn the low speed screw (L)

clockwise, no further than stop, 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).

Fine Tuning for Operation at High
Altitude

A slight correction of the setting may be
necessary if the engine does not run
satisfactorily:

N Carry out the standard setting.
N Warm up the engine.
N Turn high speed screw (H) slightly

clockwise (leaner) – no further than
stop.

Spark Plug

If there is a loss of engine power, the
machine is difficult to start or runs poorly
at idle, first check the spark plug.

Install a new spark plug after
approximately 100 operating hours or
earlier if the electrodes are
eroded/corroded.

The 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 degrade performance.

Removing the spark plug

N Pull off the spark plug boot (1)

vertically.

N Unscrew the spark plug (2).

Checking the Spark Plug

N Clean dirty spark plug.
N Check electrode gap (A) and

readjust if necessary – see chapter

"Specifications."
N 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, e.g.

operating at part load.

NOTICE

After returning from high altitude, reset
the carburetor to the standard setting.

If the setting is too lean there is a risk of
engine damage due to insufficient
lubrication and overheating.

BR 450, BR 450 C

23

English

2

1

0000-GXX-1831-A0

3

3

002BA178 KN

2

WARNING

To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press the spark plug
boot (1) snugly onto the spark plug
terminal (2).

Do not use a spark plug with a
detachable SAE adapter terminal (3).
Arcing may occur that could ignite
combustible fumes and cause a fire.
This can result in serious injuries or
damage to property.

N Only use resistor type spark plugs

with solid, non-threaded terminals

Installing the spark plug

N Screw the spark plug (3) into the

cylinder and fit the boot (2) (press it
down firmly).

Spark Arresting Screen in
Muffler

Spark arresting screen in muffler

WARNING

To reduce the risk of fire caused by hot
particles escaping from the machine,
never operate the machine without a
spark arresting screen, or with the spark
arresting screen damaged. Do not
modify the muffler or spark arresting
screen. To reduce the risk of fire from
accumulated debris such as pine
needles, branches or leaves, ensure
that the muffler plugs are in place before
taking up work.

NOTICE

According to the law or regulations in
some countries or federal states, certain
operations may only be carried out if a
properly serviced spark arresting screen
is provided.

N If the engine is down on power,

check the spark arresting screen in

the muffler.
N If the muffler plugs are missing or

damaged, mount new plugs.
STIHL recommends that maintenance

and repair work be carried out only by
authorized STIHL dealers.

24

BR 450, BR 450 C