Stihl Fs 55 R Instruction Manual

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STIHL FS 55
Warning!
Read and follow all safety 
precautions in Instruction Manual – 
improper use can cause serious or 
fatal injury.
Advertencia!
Lea y siga todas las precauciones 
de seguridad dadas en el manual 
de instrucciones – el uso incorrecto 
puede causar lesiones graves o 
mortales.
Instruction Manual
Manual de instrucciones 
						

							Instruction Manual
1 - 47
Manual de 
instrucciones
49 - 99 
						

							Original Instruction Manual Printed on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled. © ANDREAS STIHL AG & Co. KG, 2011
0458-233-8621-C. M23-8.A11.CP. 
0000000063_004_GB
FS 55, FS 55 C, FS 55 R, FS 55 RCEnglish
1
{
Contents
Allow only persons who fully understand 
this manual to operate your trimmer / 
brushcutter.
To receive maximum performance and 
satisfaction from your STIHL trimmer / 
brushcutter, 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 trimmer / 
brushcutter. 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.
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. Guide to Using this Manual 2
Safety Precautions and Working 
Techniques 3
Approved Combinations of Cutting 
Attachment, Deflector, Handle and 
Harness 16
Mounting the Bike Handle 17
Mounting the Loop Handle 19
Fitting the Carrying Ring 20
Mounting the Deflector 20
Mounting the Cutting Attachment 21
Fuel 24
Fueling 25
Fitting the Harness 25
Balancing the Trimmer/Brushcutter 26
Starting / Stopping the Engine 27
Operating Instructions 30
Cleaning the Air Filter 31
Engine Management 31
Adjusting the Carburetor 32
Spark Plug 33
Engine Running Behavior 34
Rewind Starter 35
Lubricating the Gearbox 35
Storing the Machine 35
Sharpening Metal Cutting Blades 36
Inspections and Maintenance by 
Dealer 36
Maintenance and Care 37
Main Parts 39
Specifications 41
Special Accessories 42Maintenance and Repairs 42
STIHL Incorporated Federal 
Emission Control Warranty 
Statement 43
STIHL Incorporated California 
Exhaust and Evaporative 
Emissions Control Warranty 
Statement 45
Trademarks 47
Warning!
Because a trimmer / brushcutter is a 
high-speed cutting tool some special 
safety precautions must be observed to 
reduce the risk of personal injury. Care-
less or improper use may cause serious 
or even fatal injury. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RC English
2
Pictograms
The meanings of the pictograms 
attached to or embossed on the 
machine are explained in this manual.
Depending on the model concerned, the 
following pictograms may be on your 
machine.
Symbols in Text
Many operating and safety instructions 
are supported by illustrations.
The individual steps or procedures 
described in the manual may be marked 
in different ways:
NA bullet marks a step or procedure.
A description of a step or procedure that 
refers directly to an illustration may 
contain item numbers that appear in the 
illustration. Example:
NLoosen the screw (1).
NLever (2) ...
In addition to the operating instructions, 
this manual may contain paragraphs 
that require your special attention. Such 
paragraphs are marked with the 
symbols and signal words described 
below:Engineering Improvements
STIHL’s philosophy is to continually 
improve all of its products. As a result, 
engineering changes and improvements 
are made from time to time. Therefore, 
some changes, modifications and 
improvements may not be covered in 
this manual. If the operating 
characteristics or the appearance of 
your machine differs from those 
described in this manual, please contact 
your STIHL dealer for assistance.Guide to Using this Manual
Fuel tank for gasoline 
and engine oil mixture
Press to operate decom-
pression valve
Manual fuel pump
Press to operate manual 
fuel pump
Filler hole for gear 
lubricant
Air intake summer mode
Air intake winter mode
Handle heating
Danger!
Indicates an imminent risk of severe or 
fatal injury.
Warning!
Indicates a hazardous situation which, if 
not avoided, could result in severe or 
fatal injury.
Caution!
Indicates a risk of property damage, 
including damage to the machine or its 
individual components. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RCEnglish
3 The terminology utilized in this manual 
when referring to the power tool reflects 
the fact that different types of cutting 
attachments may be mounted on it. The 
term trimmer is used to designate an 
FS unit that is equipped with a nylon line 
head or a head with flexible plastic 
blades (i.e., the PolyCut head). A 
brushcutter designates a unit 
equipped with a rigid metal blade. Many 
FS models may be used as either a 
trimmer or a brushcutter – therefore, the 
power tool is referred in this manual as a 
trimmer / brushcutter. Some smaller 
and / or lightweight FS models may only 
be used as a trimmer, i.e., they may not 
be used with metal blades.FS models with an R on the nameplate 
were originally configured (at the time of 
distribution) as a trimmer with a loop 
handle.
Have your STIHL dealer show you how 
to operate your power tool. Observe all 
applicable local safety regulations, 
standards and ordinances.STIHL does not recommend the use of 
rigid blades when cutting in stony areas.
Use your trimmer / brushcutter equipped 
with the appropriate cutting attachment 
only for cutting grass and similar 
material.
Most of these safety precautions and 
warnings apply to the use of all STIHL 
trimmer / brushcutters. 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 trimmer / brushcutter 
involves
Safety Precautions and 
Working Techniques
Because a trimmer / 
brushcutter is a high-
speed, fast-cutting power 
tool sometimes equipped 
with sharp cutting blades, 
special safety precau-
tions must be observed to 
reduce the risk of per-
sonal injury.
It is important that you 
read, fully understand 
and observe the following 
safety precautions and 
warnings. Read the 
instruction manual and 
the safety precautions 
periodically. Careless or 
improper use may cause 
serious or fatal injury.
Warning!
As more fully explained later in these 
Safety Precautions, to reduce the risk of 
personal injury, make sure your unit is 
equipped with the proper handle, har-
ness and deflector for the type of cutting 
attachment you are using. Use only cut-
ting attachments that are specifically 
authorized by STIHL for use on your FS 
model.
Warning!
Do not lend or rent your power tool with-
out the instruction manual. Be sure that 
anyone using it understands the infor-
mation contained in this manual.
Warning!
The use of this machine may be hazard-
ous. If the rotating line or blade comes in 
contact with your body, it will cut you. 
When it comes in contact with solid for-
eign objects such as rocks or bits of 
metal, it may fling them directly or by ric-
ochet 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. 
Thrown objects, including broken heads 
or blades, may result in serious or fatal 
injury to the operator or bystanders.
Warning!
Do not use it for other purposes, since 
misuse may result in personal injury or 
property damage, including damage to 
the machine.
Warning!
Minors should never be allowed to use 
this power tool. Bystanders, especially 
children, and animals should not be 
allowed in the area where it is in use.
Warning!
To reduce the risk of injury to bystand-
ers and damage to property, never let 
your power tool run unattended. When it 
is not in use (e.g. during a work break), 
shut it off and make sure that unauthor-
ized persons do not use it. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RC English
4 1.the operator
2.the power tool
3.the use of the power tool.
THE OPERATOR
Physical Condition
You must be in good physical condition 
and mental health and not under the 
influence of any substance (drugs, 
alcohol, etc.) which might impair vision, 
dexterity or judgment. Do not operate 
this machine when you are fatigued.
These conditions reduce the hands 
ability to feel and regulate temperature, 
produce numbness and burning 
sensations and may cause nerve and 
circulation damage and tissue necrosis.
All factors which contribute to 
whitefinger disease are not known, but 
cold weather, smoking and diseases or 
physical conditions that affect blood vessels and blood transport, as well as 
high vibration levels and long periods of 
exposure to vibration are mentioned as 
factors in the development of whitefinger 
disease. In order to reduce the risk of 
whitefinger disease and carpal tunnel 
syndrome, please note the following:
–Most STIHL power tools are 
available with an anti-vibration 
(AV) system designed to reduce 
the transmission of vibrations 
created by the machine to the 
operators hands. An AV system is 
recommended for those persons 
using power tools on a regular or 
sustained basis.
–Wear gloves and keep your hands 
warm.
–Keep the AV system well 
maintained. A power tool with loose 
components or with damaged or 
worn AV elements will tend to have 
higher vibration levels.
–Maintain a firm grip at all times, but 
do not squeeze the handles with 
constant, excessive pressure. Take 
frequent breaks.
All the above-mentioned precautions do 
not guarantee that you will not sustain 
whitefinger disease or carpal tunnel 
syndrome. Therefore, continual and 
regular users should closely monitor the 
condition of their hands and fingers. If 
any of the above symptoms appear, 
seek medical advice immediately.Proper Clothing
To reduce the risk of injury, the operator 
should wear proper protective apparel.
Warning!
Be alert – if you get tired, take a break. 
Tiredness may result in loss of control. 
Working with any power tool can be 
strenuous. If you have any condition 
that might be aggravated by strenuous 
work, check with your doctor before 
operating this machine.
Warning!
Prolonged use of a power tool (or other 
machines) exposing the operator to 
vibrations may produce whitefinger dis-
ease (Raynauds phenomenon) or 
carpal tunnel syndrome.
Warning!
The ignition system of the STIHL unit 
produces an electromagnetic field of a 
very low intensity. This field may inter-
fere with some pacemakers. To reduce 
the risk of serious or fatal injury, persons 
with a pacemaker should consult their 
physician and the pacemaker manufac-
turer before operating this tool.
Warning!
The deflector provided with your power 
tool will not protect the operator from all 
foreign objects (gravel, glass, wire, etc.) 
thrown back by the rotating cutting 
attachment. Thrown objects may also 
ricochet and strike the operator. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RCEnglish
5 Be particularly alert and cautious when 
wearing hearing protection because 
your ability to hear warnings (shouts, 
alarms, etc.) is restricted.Avoid loose-fitting jackets, scarfs, 
neckties, jewelry, flared or cuffed pants, 
unconfined long hair or anything that 
could become caught on branches, 
brush or the moving parts of the unit. 
Secure hair so it is above shoulder level.
THE POWER TOOL
For illustrations and definitions of the 
power tool parts see the chapter on 
Main Parts.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 to your eyes never 
operate your power tool 
unless wearing goggles 
or properly fitted protec-
tive glasses with 
adequate top and side protection com-
plying with ANSI Z 87.1 (or your 
applicable national standard). To 
reduce the risk of injury to your face 
STIHL recommends that you also wear 
a face shield or face screen over your 
goggles or protective glasses.
Wear an approved safety hard hat to 
reduce the risk of injury to your head 
when there is a danger of head injuries.
Power tool noise may damage your 
hearing. Wear sound barriers (ear plugs 
or ear mufflers) to protect your hearing. 
Continual and regular users should 
have their hearing checked regularly.
Always wear gloves 
when handling the 
machine and metal 
blades. Heavy-duty, non-
slip gloves improve your 
grip and help to protect 
your hands.
Clothing must be sturdy 
and snug-fitting, but allow 
complete freedom of 
movement. Wear long 
pants made of heavy 
material to help protect 
your legs. Do not wear 
shorts, sandals or go 
barefoot.
Good footing is very 
important. Wear sturdy 
boots with nonslip soles. 
Steel-toed safety boots 
are recommended.
Warning!
Never modify this power tool in any way. 
Only attachments supplied by STIHL 
and expressly approved by STIHL for 
use with the specific STIHL model are 
authorized. Although certain unauthor-
ized attachments are useable with 
STIHL power tools, their use may, in 
fact, be extremely dangerous. For the 
cutting attachments authorized by 
STIHL for your unit, see the chapter 
Approved Combinations of Cutting 
Attachment, Deflector, Handle and Har-
ness in the instruction manual or the 
STIHL Cutting Attachments, Parts & 
Accessories catalog.
Warning!
To reduce the risk of injury from loss of 
control and blade or line contact, never 
carry or transport your power tool with 
the cutting attachment moving. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RC English
6 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.
Fuel
Your STIHL power tool uses an oil- 
gasoline mixture for fuel (see the 
chapter on Fuel of your instruction 
manual).Fueling Instructions
In order to reduce the risk of burns and 
other personal injury from escaping gas 
vapor and fumes, remove the fuel filler 
cap on your power tool carefully so as to 
allow any pressure build-up in the tank 
to release slowly. Never remove the fuel 
filler cap while the engine is running.Select bare ground for fueling and move 
at least 10 feet (3 m) from the fueling 
spot before starting the engine. Wipe off 
any spilled fuel before starting your 
machine.
Different models may be equipped with 
different fuel caps.
Toolless cap with grip
To do this with this STIHL cap, raise the 
grip on the top of the cap until it is upright 
at a 90° angle. Insert the cap in the fuel 
tank opening with the raised positioning  Warning!
Always shut off the engine and make 
sure the cutting attachment has stopped 
before putting a trimmer / brushcutter 
down. When transporting it in a vehicle, 
properly secure it to prevent turnover, 
fuel spillage and damage to the unit. 
STIHL recommends that you keep 
metal blades covered with the transport 
guard (optional accessory).
389BA019 KN
Warning!
Gasoline is an extremely 
flammable fuel. If spilled 
and ignited by a spark or 
other ignition source, it 
can cause fire and seri-
ous burn injury or 
property damage. Use extreme caution 
when handling gasoline or fuel mix. Do 
not smoke or bring any fire or flame near 
the fuel or the power tool. Note that 
combustible fuel vapor may escape 
from the fuel system.
Warning!
To reduce the risk of serious injury from 
burns, never attempt to refuel the unit 
until it has been completely removed 
from the operator.
Warning!
Fuel your power tool in well-ventilated 
areas, outdoors. Always shut off the 
engine and allow it to cool before refu-
eling. Gasoline vapor pressure may 
build up inside the fuel tank depending 
on the fuel used, the weather conditions 
and the tank venting system.
Warning!
Check for fuel leakage 
while refueling and dur-
ing operation. If fuel 
leakage is found, do not 
start or run the engine 
until the leak is fixed and 
any spilled fuel has been wiped away. 
Take care not to get fuel on your cloth-
ing. If this happens, change your 
clothing immediately.
Warning!
In order to reduce the risk of fuel spill-
age and fire from an improperly 
tightened fuel cap, correctly position 
and tighten the fuel cap in the fuel tank 
opening.
001BA220 KN 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RCEnglish
7 marks on the grip of the cap and on the 
fuel tank opening lining up. Using the 
grip, press the cap down firmly while 
turning it clockwise as far as it will go 
(approx. 1/4 turn).
Misaligned, damaged or broken cap
NIf the cap does not drop fully into the 
opening when the positioning marks 
line up and/or if the cap does not 
tighten properly when twisted, the 
base of the cap may be prematurely 
rotated (in relation to the top) to the 
closed position. Such misalignment 
can result from handling, cleaning 
or an improper attempt at 
tightening.NTo return the cap to the open 
position for installation, turn the cap 
(with the grip up) until it drops fully 
into the tank opening. Next, twist the 
cap counterclockwise as far as it will 
go (approx. 1/4 turn) – this will twist 
the base of the cap into the correct 
position. Then, twist the cap 
clockwise, closing it normally.
NIf your cap still does not tighten 
properly, it may be damaged or 
broken; immediately stop use of the 
unit and take it to your authorized 
STIHL dealer for repair.Screw Cap
See also the Fueling chapter in your 
Instruction Manual for additional 
information.
Before Starting Fold the grip flush with 
the top of the cap. Grip 
the cap and check for 
tightness. If the grip does 
not lie completely flush 
with the cap and the 
detent on the grip does 
not fit in the correspond-
ing recess in the filler 
opening, or if the cap is 
loose in the filler opening, 
the cap is not properly 
seated and tightened and 
you must repeat the 
above steps.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
001BA227 KN
001BA226 KN
Warning!
Unit vibrations can cause 
an improperly tightened 
fuel filler cap to loosen or 
come off and spill quanti-
ties of fuel. In order to 
reduce the risk of fuel 
spillage and fire, tighten the fuel filler 
cap by hand as securely as possible.
Warning!
Always check your power tool for proper 
condition and operation before starting, 
particularly the throttle trigger, throttle 
trigger lockout, stop switch, cutting 
attachment, deflector and harness. The 
throttle trigger must move freely and 
always spring back to the idle position. 
Never attempt to modify the controls or 
safety devices.
Warning!
Never operate your power tool if it is 
damaged, improperly adjusted or main-
tained, or not completely or securely 
assembled. 
						

							FS 55, FS 55 C, FS 55 R, FS 55 RC English
8 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.As can be seen in that chart, some 
cutting attachments may require you to 
change your deflector, handle and / or 
harness.
Keep the deflector (and the attached 
skirt where appropriate) adjusted 
properly at all times (see chapters on 
Mounting the Deflector and Mounting 
the Cutting Attachment of your 
instruction manual).
Arrows on the deflector (A) (as seen 
from the underside) show the correct 
direction of rotation of the cutting 
attachment. When viewed from above, 
however, the cutting attachment rotates 
counterclockwise.Adjust carrying harness and hand grip to 
suit your size before starting work. The 
machine should be properly balanced as 
specified in your instruction manual for 
proper control and less fatigue in 
operation. To be better prepared in case 
of an emergency, practice releasing the 
unit from the harness as quickly as 
possible.
Starting
Start the engine at least 10 feet (3 m) 
from the fueling spot, outdoors only.
For specific starting instructions, see the 
appropriate section of your manual. 
Place the power tool on firm ground or 
other solid surface in an open area. 
Maintain good balance and secure 
footing.
Once the engine has started, 
immediately blip the throttle trigger, 
which should release the starting throttle 
and allow the engine to slow down to 
idle.
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!
Do not attach any cutting attachment to 
a unit without proper installation of all 
required parts. Failure to use the proper 
parts may cause the blade or head to fly 
off and seriously injure the operator or 
bystanders.
Warning!
The cutting attachment must be prop-
erly tightened and in safe operating 
condition. Inspect for loose parts (nuts, 
screws, etc.) and for cracked or dam-
aged heads or cracked, bent, warped or 
damaged blades. Replace damaged 
heads or blades before using the power 
tool. Always keep blades sharp.
Warning!
Check that the spark plug boot is 
securely mounted on the spark plug – a 
loose boot may cause arcing that could 
ignite combustible fumes and cause a 
fire.
Warning!
To reduce the risk 
of personal injury 
to the operator 
from blade or line 
contact and 
thrown objects, make sure your unit is 
equipped with the proper deflector, han-
dle and harness for the type of cutting 
attachment being used (see chart in the 
chapter on Approved Combinations of 
Cutting Attachment, Deflector, Handle 
and Harness).
A
000BA006 KN
Warning!
To reduce the risk of injury from blade or 
line contact, be absolutely sure that the 
cutting attachment is clear of you and all 
other obstructions and objects, includ-
ing the ground, because when the 
engine starts at starting-throttle, engine 
speed will be fast enough for the clutch 
to engage and move the cutting 
attachment.