Stihl Fs 450 K Manual

							Instruction Manual    
Manual de instrucciones
Warning!
Read and follow all safety precautions in 
Instruction Manual – improper use can cause 
serious or fatal injury.
Advertencia!
Lea y siga todas las precauciones de 
seguridad dadas en el manual de 
instrucciones – el uso incorrecto puede 
causar lesiones graves o mortales.
STIH)
STIHL FS 300, 350, 400, 450, 480 
						

							1 FS 300, FS 350, FS 400, FS 450, FS 480English / USA
BA_SE_081_009_01_07.fm Printed on chlorine-free paper.
Printing inks contain vegetable oils; paper can be recycled. © ANDREAS STIHL AG & Co. KG, 2008 
0458 255 8621 A. M0.5. B8. Rei. Printed in Germany 
STIHlContentsGuide to Using this Manual  ..............  2
Safety Precautions and 
Working Techniques  .........................  3
Approved Combinations of 
Cutting Tool, Deflector, 
Stop and Harness  ...........................  18
Mounting the Bike Handle  ..............  20
Adjusting the Throttle Cable  ...........  21
Mounting the Deflectors 
and Limit Stop  .................................  22
Mounting the Cutting Tools  .............  23
Fuel ................................................  26
Fueling ............................................  27
Fitting the Harness  .........................  27
Balancing the Machine  ...................  28
Starting / Stopping the Engine  ........  28
Operating Instructions  ....................  30
Cleaning the Air Filter  .....................  31
Cleaning the Air Filter  .....................  31
Motor Management  ........................  32Adjusting the Carburetor  ................  32
Winter Operation  ............................  33
Electric Handle Heating  .................  34
Checking the Spark Plug  ................  34
Engine Running Behavior  ..............  35
Lubricating the Gearbox  .................  36
Replacing the Starter 
Rope and Rewind Spring  ...............  36
Storing the Machine  .......................  38
Sharpening 
Metal Cutting Tools .........................  39
Maintenance Chart  .........................  40
Parts and Controls  .........................  42
Specifications .................................  44
Special Accessories  .......................  45
Maintenance and Repairs  ..............  45
STIHL Incorporated 
Federal Emission Control 
Warranty Statement ........................  46
Trademarks ....................................  48Allow only persons who understand this 
manual to operate your clearing saw. 
To receive maximum performance and 
satisfaction from your STIHL brush-
cutter, it is important that you read and 
understand the maintenance and safety 
precautions, starting on page 3, before 
using your clearing saw. 
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 clearing saw is a high-speed 
cutting tool some special safety pre-
cautions must be observed to reduce
the risk of personal injury. 
Careless or improper use may cause 
serious or even fatal injury. Make sure 
your unit is equipped with the proper 
deflector, handle and harness for the 
type of cutting attachment being used. 
Always wear proper eye protection.
STIHLs philosophy is to continually 
improve all of its products. As a result, 
engineering changes and improve-
ments are made from time to time. If  the 
operating characteristics or the appear-
ance of your clearing saw differs from 
those described in this manual, please 
contact your STIHL dealer for informa-
tion and assistance. 
						

							2 English / USA
FS 300, FS 350, FS 400, FS 450, FS 480PictogramsAll the pictograms attached to the 
machine are shown and explained in  
this manual.
The operating and handling instructions 
are supported by illustrations.Symbols in textThe 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 under-
standing 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 featuresThis 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 improvementsSTIHL’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.
Guide to Using this Manual 
						

							3 FS 300, FS 350, FS 400, FS 450, FS 480English / USA
Warning!
Because a clearing saw is 
a high-speed, fast-cutting 
power tool, special safety 
precautions must be 
observed to reduce the risk of personal 
injury.
It is important that you 
read, fully understand and 
observe the following 
safety precautions and 
warnings. Read the 
owners manual and the 
safety instructions periodically. Careless 
or improper use of any clearing saw may 
cause serious or fatal injury.
Have your STIHL dealer show you how 
to operate your clearing saw. Observe 
all applicable local safety regulations, 
standards and ordinances.
!
Warning!
Do not lend or rent your clearing saw 
without the owners manual. Be sure that 
anyone using your clearing saw 
understands the information contained 
in this manual.
!
Warning!
The use of any clearing saw may be 
hazardous. If the rotating cutting tool 
comes in contact with your body, it will 
cut you. When it comes in contact with 
solid foreign objects such as rocks or 
bits of metal, it may fling them directly or 
by ricochet in the direction of bystanders 
or the operator.
Striking such objects could damage the 
cutting attachment and may cause 
blades to crack, chip or break. 
STIHL does not recommend the use of 
rigid blades when cutting in stony areas. 
Thrown objects or damaged blades may 
result in serious or fatal injury to the 
operator or bystanders.
!
Warning!
Minors should never be allowed to use a 
clearing saw. Bystanders, especially 
children, and animals should not be 
allowed in the area where a clearing saw 
is in use.
Never let the clearing saw run 
unattended.Most of these safety precautions and 
warnings apply to the use of all STIHL 
clearing saws. Different models may 
have different parts and controls. See 
the appropriate section of your owners 
manual for a description of the controls 
and function of the parts of your model 
clearing saw.
Safe use of a clearing saw involves
1. the operator
2. the clearing saw
3. the use of the clearing saw.
THE OPERATORPhysical 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 judgement. Do not operate a 
clearing saw when you are fatigued.
Be alert – if you get tired while operating 
your clearing saw, take a break. 
Tiredness may result in loss of control. 
Working with any clearing saw can be 
strenuous. If you have any condition that 
might be aggravated by strenuous work, 
check with your doctor before operating 
a clearing saw. 
Safety Precautions and 
Working Techniques 
						

							4 English / USA
FS 300, FS 350, FS 400, FS 450, FS 480!
Warning!
Prolonged use of a clearing saw (or 
other machines) exposing the operator 
to vibrations may produce whitefinger 
disease (Raynauds phenomenon) or 
carpal tunnel syndrome. 
These conditions reduce the hands 
ability to feel and regulate temperature, 
produce numbness and burning 
sensations and may cause nerve and 
circulation damage and tissue necrosis.
All factors which contribute to 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 
factors in the development of whitefinger 
disease. In order to reduce the risk of 
whitefinger disease and carpal tunnel 
syndrome, please note the following:– Most STIHL power tools are 
available with an anti-vibration 
(AV) system designed to reduce 
the transmission of vibrations 
created by the engine to the 
operators hands. An AV system is 
recommended for those persons 
using power tools on a regular or 
sustained basis.
– Wear gloves and keep your hands 
warm.
– Keep the AV system well 
maintained. A clearing saw with 
loose components or with damaged 
or worn AV buffers will tend to have 
higher vibration levels.
– Maintain a firm grip at all times, but 
do not squeeze the handles with 
constant, excessive pressures and 
take frequent breaks. 
All the above mentioned precautions do 
not guarantee that you will not sustain 
whitefinger disease or carpal tunnel 
syndrome. Therefore continual and 
regular users should monitor closely the 
condition of their hands and fingers. If 
any of the above symptoms appear, 
seek medical advice immediately.
!
Warning!
The ignition system of your unit 
produces an electromagnetic field of a 
very low intensity. This field may 
interfere with some pacemakers. To 
reduce the risk of serious or fatal injury, 
persons with pacemaker should consult 
their physician and the pacemaker 
manufacturer before operating this tool.
Proper Clothing
!
Warning!
To reduce the risk of injury, the operator 
should wear proper protective apparel. 
The deflector provided with your clearing 
saw may not protect the operator from 
all foreign objects (gravel, glass, wire, 
etc.) thrown by the rotating cutting 
attachment. Thrown objects may also 
ricochet and strike the operator.  
						

							5 FS 300, FS 350, FS 400, FS 450, FS 480English / USA
!
Warning!
To reduce the risk of injury 
to your eyes never 
operate a clearing saw 
unless wearing goggles or 
properly fitted safety 
glasses with adequate top 
and side protection complying with ANSI 
Z 87.1 (or your applicable national 
standard). To reduce the risk of injury to 
your face STIHL recommends that you 
also wear a face shield or face screen 
over your goggles or safety glasses.
!
Warning!
Clearing saw 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. 
Protect your hands with 
gloves when handling the 
clearing saw and the 
cutting tool. Heavy-duty, 
nonslip gloves improve 
your grip and protect your 
hands.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 longhair or 
anything that could become caught on 
branches, brush or moving parts of the 
unit. Wear long pants made of heavy 
material to protect your legs. Do not 
wear shorts, pants, sandals or go bare 
foot. Secure hair so it is above shoulder 
level.
Good footing is most 
important in clearing saw 
work. 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 CLEARING SAWFor illustrations and definitions of the 
clearing saw parts see the chapter on 
Parts and Controls.!
Warning!
Never modify a clearing saw in any way. 
Only attachments supplied by STIHL or 
expressly approved by STIHL for use 
with the specific STIHL clearing saw 
models are authorized. Although certain 
unauthorized attachments are useable 
for the STIHL clearing saw, their use 
may, in fact, be extremely dangerous. 
						

							6 English / USA
FS 300, FS 350, FS 400, FS 450, FS 480THE USE OF THE 
CLEARING SAWTransporting the clearing saw!
Warning!
Always turn off the engine and make 
sure the cutting attachment has stop-
ped before putting a clearing saw down. 
When transporting your clearing saw in 
a vehicle, properly secure it to prevent 
turnover, fuel spillage and damage to the 
clearing saw. Keep metal cutting tools 
covered with the transport guard 
(optional accessory). 
Preparation for the use of the clearing 
saw
Adjust carrying harness and hand grip to 
suit your size before starting work. The 
machine should be properly balanced as 
specified in your owners manual for 
proper control and less fatigue in 
operation. 
Always check your clearing saw for 
proper condition and operation before 
starting, particularly the throttle trigger, 
throttle trigger interlock (if applicable), 
stopswitch, cutting tool, deflector and 
harness.Arrows on the deflector (A) and stop (B) 
show the correct direction of rotation of 
the cutting tool.
The throttle trigger must move freely and 
always spring back to the idle position. 
The cutting tool must be properly 
tightened and in safe operating 
condition. Inspect for loose parts (nuts, 
screws, etc.) and for cracked, bent, 
warped or damaged blades.Fueling
Your STIHL clearing saw uses an oil- 
gasoline mixture for fuel (see the chap-
ter on Fuel of your owners 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 clearing saw.
Fueling Instructions 
!
Warning!
Fuel your clearing saw 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. 
A
000BA006 KN
B
000BA007 KN 
						

							7 FS 300, FS 350, FS 400, FS 450, FS 480English / USA
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 clearing saw carefully so as 
to allow any pressure build-up in the 
tank to release slowly. Never remove 
fuel filler cap while engine is running. 
Select bare ground for fueling and move 
at least 10 feet (3 m) from the fueling 
spot before starting the engine. Wipe off 
any spilled fuel before starting your 
clearing saw and check for leakage.
!
Warning!
Check for fuel leakage while refueling 
and during operation. If fuel or oil 
leakage is found, do not start or run the 
engine until leak is fixed and spilled fuel 
has been wiped away. Take care not to 
get fuel on your clothing. If this happens, 
change your clothing immediately.
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.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 with as much force as possible.
Operating instructions
!
 Warning!
Improper use of 
any clearing saw 
can cause serious 
or fatal personal 
injury.  To reduce 
the risk of personal injury to the operator 
from blade contact and thrown objects, 
m a k e  s u r e  y o u r  u n i t  i s  e q u i p p e d  w i t h  t h e  
proper deflector, handle and harness for 
the type of cutting attachment being 
used (see chart in chapters on Approved 
Combinations of Cutting Tool, Deflector, 
Handle and Harness).  
						

							8 English / USA
FS 300, FS 350, FS 400, FS 450, FS 480 Keep the deflector (and the skirt where 
appropriate) adjusted properly at all 
times (see chapter on mounting the 
various cutting tools of your owners 
manual).
Starting!
Warning!
Your clearing saw is a one-person 
machine. Once started, it may fling 
foreign objects for a great distance.
To reduce the risk of eye and other injury 
insure that bystanders are at least 
50 feet (15 m) away. Bystanders should 
be encouraged to wear eye protection. 
Stop the engine and cutting tool 
immediately if you are approached. Start 
and operate your clearing saw without 
assistance. For specific starting 
instructions, see the appropriate section 
of your manual. Place the clearing saw 
on firm ground or other solid surface in 
an open area. Maintain a good balance 
and secure footing.
!
Warning!
To reduce the risk of injury from loss of 
control, 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 
turn the cutting tool.
!
Warning!
When you pull the starter grip, dont 
wrap the starter rope around your hand. 
Do not allow the grip to snap back, but 
guide the starter rope to rewind it 
properly. Failure to follow this procedure 
may result in injury to hand or fingers 
and may damage the starter 
mechanism.
With the engine running but at idle, 
attach the clearing saw to the spring 
hook of your harness (see appropriate 
chapter of this manual).Catalytic converter
!
Warning!
Some STIHL clearing saw 
models 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 conven-
tional mufflers, always set your clearing 
saw 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.
15m (50ft)
      
        
         
 
         
    
						

							9 FS 300, FS 350, FS 400, FS 450, FS 480English / USA
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!
To reduce the risk of fire or burn injury, 
let the unit cool down before refueling 
your clearing saw after use.
!
Warning!
Never disassemble or modify your 
muffler. The muffler could be damaged 
and cause an increase in heat radiation 
or sparks, thereby increasing the risk 
of fire or burn injury. You may also 
permanently damage the engine. Have 
your muffler serviced and repaired by 
your STIHL Servicing Dealer only.
!
Warning!
To reduce the risk of fire or burn injury, 
keep the area around the muffler clean. 
Remove all debris such as pine needles, 
branches or leaves.
!
Warning!
An improperly mounted or damaged 
cylinder housing or a damaged/
deformed muffler shell may interfere 
with the cooling effect 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.Working Conditions
Operate and start your clearing saw only 
outdoors in a ventilated area. 
Operate the clearing saw under good 
visibility and daylight conditions only. 
Work carefully.
!
Warning!
Your clearing saw 
produces toxic exhaust 
fumes as soon as the 
engine is running. These 
gases (e.g. carbon 
monoxide) may be 
colorless and odorless. To reduce the 
risk of serious or fatal injury from 
inhaling toxic fumes, never run the 
clearing saw indoors or in poorly 
ventilated locations.
!
Warning!
Use of this product can generate dust 
and fumes containing chemicals known 
to cause respiratory disease, cancer, 
birth defects, or other reproductive 
harm. If you are unfamiliar with the risks 
associated with the particular dust or 
fume at issue, consult your employer, 
governmental agencies such as OSHA 
and NIOSH and other sources on 
hazardous materials.