Stihl FS 55 Instruction Manual

FS 55

Instruction Manual2 - 35

English

Contents

1 Guide to Using this Manual.........................2

2 Safety Precautions and Working Techni‐

ques............................................................ 2

3 Approved Combinations of Cutting Attach‐

ment, Deflector, Handle and Harness.......10

4 Mounting the Bike Handle.........................11

5 Mounting the Loop Handle........................13

6 Fitting the Carrying Ring........................... 14

7 Mounting the Deflector..............................15

8 Mounting the Cutting Attachment..............16

9 Fuel........................................................... 19

10 Fueling...................................................... 20

11 Fitting the Harness....................................20

12 Balancing the Machine..............................21

13 Starting / Stopping the Engine.................. 22

14 Transporting the Unit................................ 25

15 Operating Instructions...............................26

16 Cleaning the Air Filter............................... 26

17 Adjusting the Carburetor........................... 27

18 Spark Plug................................................ 29

19 Engine Running Behavior......................... 29

20 Storing the Machine.................................. 29

21 Sharpening Metal Cutting Blades............. 30

22 Maintaining the Mowing Head...................30

23 Inspections and Maintenance by Dealer...31

24 Maintenance and Care..............................32

25 Main Parts.................................................33

26 Specifications............................................33

27 Maintenance and Repairs......................... 34

28 Disposal.................................................... 35

29 EC Declaration of Conformity................... 35

Dear Customer,

Thank you for choosing a quality engineered
STIHL product.

It has been built using modern production techni‐
ques and comprehensive quality assurance.
Every effort has been made to ensure your satis‐
faction and trouble-free use of the product.

Please contact your dealer or our sales company
if you have any queries concerning this product.

Your

Dr. Nikolas Stihl

1 Guide to Using this Manual

1.1 Pictograms

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

Depending on the model concerned, the follow‐
ing pictograms may be attached to your
machine.

Fuel tank; fuel mixture of gasoline
and engine oil

Operate decompression valve

Manual fuel pump

Operate manual fuel pump

Tube of grease

Intake air: Summer operation

Intake air: Winter operation

Handle heating

1.2 Symbols in text

WARNING

Warning where there is a risk of an accident or
personal injury or serious damage to property.

NOTICE

Caution where there is a risk of damaging the
machine or its individual components.

1.3 Engineering improvements

STIHL's philosophy is to continually improve all
of its products. For this reason we may modify
the design, engineering and appearance of our
products periodically.

Therefore, some changes, modifications and
improvements may not be covered in this man‐
ual.

2 Safety Precautions and

Working Techniques

Because the machine is a high-speed
fast-cutting power tool, special safety
precautions must be observed to
reduce the risk of personal injury.

Original Instruction Manual

0000006615_017_GB

Printed on chlorine-free paper

Printing inks contain vegetable oils, paper can be recycled.

© ANDREAS STIHL AG & Co. KG 2022

0458-233-8321-G. VA1.B22.

2 0458-233-8321-G

2 Safety Precautions and Working Techniques English

It is important that you read and
understand the User Manual before
commissioning and keep it in a safe
place for future reference. Non-com‐
pliance with the User Manual may
cause serious or even fatal injury.

Observe all applicable local safety regulations,
e.g. by trade organizations, social insurance
institutions, labor safety authorities etc.

If you have never used a power tool before:
Have your dealer or other experienced user
show you how to operate your machine – or
attend a special course to learn how to operate
it.

Minors should never be allowed to use the
machine – except for apprentices over the age of
16 when working under supervision.

Children, animals and bystanders must remain at
a distance.

When not using the machine, it must be laid
down in such a way that it does not endanger
anyone. Ensure that the machine cannot be
used without authorization.

The user is responsible for accidents or risks
involving third parties or their property.

Do not lend or rent your power tool without the
User Manual. Be sure that anyone using it under‐
stands the information contained in this manual.

The use of machines that emit noise may be limi‐
ted to certain hours of the day as specified by
national and/or regional or local regulations.

Anyone operating the machine must be well res‐
ted, in good physical health and in good mental
condition.

If you have any condition that might be aggrava‐
ted by strenuous work, check with your doctor
before operating a machine.

If you have a pacemaker: The ignition system of
your machine produces an electromagnetic field
of very low intensity. This field may interfere with
some pacemakers. STIHL recommends that per‐
sons with pacemakers consult their physician
and the pacemaker manufacturer to reduce any
health risk.

Anyone who has consumed alcohol or drugs or
medicines affecting their ability to react must not
operate a power tool.

Depending on the cutting attachment fitted, use
your power tool only for cutting grass, wild
growth, shrubs, scrub, bushes, small diameter
trees and similar materials.

0458-233-8321-G 3

The machine must not be used for any other pur‐
poses – risk of accidents!

Only use cutting attachments and accessories
that are explicitly approved for this power tool
model by STIHL or are technically identical. If
you have any questions in this respect, consult
your dealer. Use only high quality parts and
accessories. in order to avoid the risk of acci‐
dents and damage to the machine.

STIHL recommends the use of original STIHL
tools and accessories. They are specifically
designed to match the product and meet your
performance requirements.

Never attempt to modify your power tool in any
way since this may increase the risk of personal
injury. STIHL excludes all liability for personal
injury and damage to property caused while
using unauthorized attachments.

Do not use a high-pressure washer to clean the
power tool. The solid jet of water may damage
parts of the unit.

The guard provided with your machine may not
protect the operator from all foreign objects
(gravel, glass, wire etc.) ejected by the revolving
cutting attachment. Ejected objects may also ric‐
ochet and strike the operator.

2.1 Clothing and equipment

Wear proper protective clothing and equipment.

Clothing must be sturdy but allow
complete freedom of movement.
Wear close-fitting clothes such as a
boiler suit, not a loose jacket.

Do not wear clothing which could
become trapped in wood, brush or
moving parts of the machine. Do not
wear a scarf, necktie or jewelry. Tie
up and confine long hair above your
shoulders.

Wear safety boots with steel toe caps
and non-slip soles.

Sturdy shoes with non-slip shoes are permissible
only when using mowing heads.

WARNING

To reduce the risk of eye injuries,
wear close-fitting safety glasses in
accordance with European Standard
EN 166. Make sure the safety
glasses are a snug fit.

002BA079 KN

English 2 Safety Precautions and Working Techniques

Wear face protection and make sure it is a good
fit. Face protection alone is not sufficient to pro‐
tect the eyes.

Wear "personal" sound protection, e.g. ear
defenders.

Wear a safety hard hat for thinning operations,
when working in high scrub and where there is a
danger of head injuries from falling objects.

Wear sturdy protective gloves made
of a resistant material (e. g. leather).

STIHL can supply a comprehensive range of per‐
sonal protective equipment.

2.2 Transporting the machine

2.3 Refueling

Gasoline is an extremely flammable
fuel. Keep clear of naked flames. Do
not spill any fuel – do not smoke.

Always shut off the engine before refueling.

Do not fuel a hot engine – fuel may spill and
cause a fire.

Open the fuel cap carefully to allow any pressure
build-up in the tank to release slowly and avoid
fuel spillage.

Only refuel the machine in a well ventilated
place. If fuel has been spilled, immediately clean
the machine – do not allow your clothes to be
splashed with fuel. If that happens, change your
clothes at once.

After refueling, close the fuel cap as
tightly as possible.

This helps reduce the risk of unit vibrations caus‐
ing an incorrectly tightened fuel cap to loosen or
come off and spill quantities of fuel.

Check for leaks. Do not start the engine if there
is a fuel leak – serious or fatal burns could result!

2.4 Before starting

Check that your power tool is properly assem‐
bled and in good condition – refer to appropriate
chapters in the User Manual.

Check the fuel system for leaks, especially the

–

visible parts, e. g., fuel cap, hose connections,
manual fuel pump (only in machines with a
manual fuel pump). In case of leakage and
damage, do not start the engine – risk of fire!
Have the machine serviced by a dealer before
using it
Use only an approved combination of cutting

Always stop the engine.

Carry the machine hanging on the harness or by
the shaft so that it is balanced.

To reduce the risk of cut injuries, fit transport
guard on the cutting attachment, even when car‐
rying the tool for short distances – see also
"Transporting the Unit".

Avoid touching hot parts of the
machine and gearbox – risk of burns!

By vehicle: When transporting in a vehicle, prop‐
erly secure your machine to prevent turnover,
damage and fuel spillage.

–

attachment, deflector, handle and harness. All
parts must be assembled properly and
securely
Slide control / stop switch must move easily to

–

STOP or 0
Throttle trigger lockout (if installed) and throttle

–

trigger must move easily – the throttle trigger
must return to the idle position automatically
Check that the spark plug boot is secure – a

–

loose boot may cause sparking that could
ignite combustible fumes and cause a fire!
Cutting attachment or interchangeable attach‐

–

ment: correctly fitted, secure and in perfect
condition

4 0458-233-8321-G

002BA055 KN

002BA080 KN

15m (50ft)

2 Safety Precautions and Working Techniques English

Safety devices (e. g., deflector for cutting

–

attachments, rider plate) for damage and/or
wear. Always replace damaged parts. Do not
use the machine with a damaged deflector or
worn rider plate (if the writing and arrows are
no longer discernible)
Never attempt to modify the controls or safety

–

devices
Keep the handles dry and clean – free from oil

–

2.6 Holding and guiding the machine

Always hold the unit firmly with both hands on
the handles.

Make sure you always have good balance and
secure footing.

2.6.1 For versions with bike handle

and dirt – this is important for safe control of
the machine
Adjust the harness and handle(s) to suit your

–

height and reach Observe the chapter "Fitting
the Harness" – "Balancing the machine"

To reduce the risk of personal injury, do not
operate your power tool if it is damaged or not
properly assembled!

To prepare for emergencies when using a har‐
ness: Practice setting down the machine quickly.
To avoid damage, do not throw the unit to the
ground when practicing.

2.5 Starting the engine

Start the engine at least 3 meters from the fuel‐

Right hand on control handle, left hand on grip
on handlebar.

2.6.2 For versions with loop handle

ing spot, outdoors only.

Place the unit on firm ground in an open area.
Make sure you have good balance and secure
footing. Hold the unit securely. The cutting
attachment must be clear of the ground and all
other obstructions because it may begin to run
when the engine starts.

This is a one-person machine – ensure that there
is no-one within 15 meters of the machine, not
even when starting the power tool! Risk of injury
due to ejected objects!

Avoid contact with the cutting attach‐
ment – risk of injury!

For versions with loop handle and loop handle
with barrier bar, left hand on the loop handle,
right hand on the control handle – even if you are
left-handed.

Do not drop-start the power tool –
start the engine as described in the
User Manual. The cutting attachment
runs on for a short while after releas‐
ing the throttle trigger – coasting
effect!

Check engine idling: The cutting attachment
must remain at a standstill when the engine idles
– throttle trigger released.

Keep easily combustible materials (e. g., wood
chips, bark, dry grass, fuel) away from hot
exhaust gases and hot muffler surfaces – risk of
fire!

2.7 While working

Make sure you always have good balance and
secure footing.

In the event of impending danger or in an emer‐
gency, switch off the engine immediately - move
the slide control/stop switch to STOP or 0.

Within a wide area around the workplace, there
is a risk of accident by ejected objects, therefore
ensure that there is no-one within a 15 m radius
of the machine. This distance must also be main‐
tained in relation to objects (vehicles, window

0458-233-8321-G 5

English 2 Safety Precautions and Working Techniques

panes) – risk of property damage! Even at a dis‐
tance over 15 m, danger cannot be ruled out.

Check that the engine is properly idling so that
the cutting tool will not continue rotating after you
release the throttle trigger.

Check and correct the idle speed setting at regu‐
lar intervals. If the cutting attachment still rotates
at idle speed, have your dealer make proper
adjustments or repairs. STIHL recommends you
have this work done by a STIHL servicing dealer.

Take special care in slippery conditions – damp,
snow, ice, on slopes or uneven ground.

Watch out for obstacles: tree stumps, roots – risk
of tripping or stumbling!

Only work while standing on the ground, never
on a ladder or mobile elevated work platform.

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

Take breaks when you start getting tired or feel‐
ing fatigue – risk of accidents!

Work calmly and carefully – in daylight conditions
and only when visibility is good. Proceed with
caution, do not put others in danger.

As soon as the engine is running, the
power machine generates toxic
exhaust gas.As soon as the engine is
running, the power machine gener‐
ates toxic exhaust gas. These gases
may be odorless and invisible and
may contain unburned hydrocarbons
and benzene. Never run the engine
indoors or in poorly ventilated loca‐
tions, even if your model is equipped
with a catalytic converter.

To reduce the risk of serious or fatal injury from
breathing toxic fumes, ensure proper ventilation
when working in trenches, hollows or other con‐
fined locations.

Stop work immediately if you start suffering from
nausea, headaches, impaired vision (e.g. your
field of vision gets smaller), impaired hearing,
dizziness, or impaired concentration – these
symptoms may possibly be the result of too-high
exhaust gas concentration – Risk of accidents!

Operate your power tool so that it produces a
minimum of noise and emissions – do not run the
engine unnecessarily, accelerate the engine only
when working.

To reduce the risk of fire, do not smoke while
operating or standing near your power tool. Com‐

bustible fuel vapor may escape from the fuel sys‐
tem.

Dust, fumes and smoke produced while working
may be hazardous to health. Wear respiratory
protection in case of heavy dust or smoke emis‐
sion.

If your power 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 – see also
"Before Starting".

Check in particular that the fuel system has no
leaks and the safety equipment is fully operative.
Never use a power tool that is no longer safe to
operate. In case of doubt, contact a dealer.

Do not operate your power tool in the starting
throttle position – engine speed cannot be con‐
trolled in this position.

To reduce the risk of injuryfrom ejec‐
ted objects, never operate the unit
without the proper deflector for the
type of cutting attachment being
used.

Check the work site – rocks, metal
objects etc. may be caught up and
ejected – possibly over a distance of
15 m – risk of injury! – They can also
damage the cutting attachment and
other property (e. g. parking vehicles,
windows).

Be particularly careful when working on difficult,
densely grown terrain.

When mowing in high shrubbery, under shrub‐
bery and hedges: Hold the cutting tool at a work‐
ing height of at least 15 cm – avoid risks to ani‐
mals.

Always shut off the engine before leaving the
unit unattended.

Examine the cutting attachment periodically at
short intervals and as soon as you note any
noticeable changes:

Stop the engine, hold the machine securely,

–

allow the cutting attachment to come to a stop
Check condition and secure fitting; watch out

–

for cracks
Ensure that the cutting blades are sharp

–

Replace damaged or blunt cutting attachments

–

immediately, even in the event of minor hair‐
line cracks

Clean grass and plant residue off the cutting
attachment mounting at regular intervals –

6 0458-233-8321-G

2 Safety Precautions and Working Techniques English

remove any accumulated material from the cut‐
ting attachment and deflector.

To reduce the risk of injury, shut off the engine
before replacing the cutting attachment.

The gearbox gets hot during opera‐
tion. Never touch the gearbox – risk
of burns!

If a rotating cutting attachment touches a rock or
another hard object, sparks can be generated
which may possibly ignite combustible materials.
Also dried-out plants and brushwood are com‐
bustible, above all in hot and dry weather. If
there is a risk of fire, do not use cutting attach‐
ments in the vicinity of combustible materials,
dried-out plants or brushwood. It is mandatory
that you ask the responsible forestry office about
current fire hazards.

2.8 Using mowing heads

Extend the cutting attachment deflector with the
attached parts specified in the User Manual.

Only use a deflector with a properly fitted blade
that limits the mowing line to the permissible
length.

For manually adjustable mowing heads, always
switch off the engine before adjusting the mow‐
ing line – risk of injury!

Misuse with mowing lines that are too long
reduces the working speed of the engine. The
constant slipping of the clutch causes overheat‐
ing and damage to important components (e. g.
clutch, plastic housing parts) – e. g. due to the
cutting attachment rotating during idling – risk of
injury!

2.9 When using metal cutting attachments

STIHL recommends the use of original STIHL
metal cutting attachments. These have been
optimized for the machine and the user’s require‐
ments.

Metal cutting attachments rotate very fast, gener‐
ating forces acting on the attachments and on
the cuttings.

Metal cutting attachments must be sharpened in
regular intervals in accordance with the instruc‐
tions.

Unevenly sharpened metal cutting attachments
generate an imbalance which may cause

extreme loads on the machine – risk of break‐
age!

Dull or improperly sharpened cutting edges can
put a higher load on the cutting attachment and
increase the risk of injuryfrom cracked or broken
parts.

After each contact of the metal cutting attach‐
ment with hard objects (e.g. stones, rocks, metal
parts), check it for damage (e.g. tears and defor‐
mation). To reduce the risk of injury, remove
burrs and other visible accumulated material
because they may become detached and ejec‐
ted at high speed during operation.

Do not continue using or attempt to repair dam‐
aged or cracked cutting attachments by means
of welding, straightening or modifying the shape
(unbalanced).

Particles or pieces may come off and hit the
operator or a bystander at a high speed – risk of
most severe injuries!

To reduce the above-named risks involved in
operating a metal cutting attachment, ensure that
the diameter of your metal cutting attachment is
not too big. Also, the attachment must not be too
heavy. It must be made of high-quality materials
and have a suitable geometry (shape, thickness).

A metal cutting attachment not made by STIHL
must not have a different weight, thickness,
shape or a larger diameter than the largest
STIHL metal cutting attachment approved for this
metal cutting attachment – risk of injury!

2.10 Vibrations

Prolonged use of the power tool may result in
vibration-induced circulation problems in the
hands (whitefinger disease).

No general recommendation can be given for the
length of usage because it depends on several
factors.

The period of usage is prolonged by:

Hand protection (wearing warm gloves)

–

Work breaks

–

The period of usage is shortened by:

Any personal tendency to suffer from poor cir‐

–

culation (symptoms: frequently cold fingers,
tingling sensations).
Low outside temperatures.

–

The force with which the handles are held (a

–

tight grip restricts circulation).

0458-233-8321-G 7

English 2 Safety Precautions and Working Techniques

Continual and regular users should monitor
closely the condition of their hands and fingers. If
any of the above symptoms appear (e.g. tingling
sensation in fingers), seek medical advice.

2.11 Maintenance and Repairs

Service the machine regularly. Do not attempt
any maintenance or repair work not described in
the instruction manual. Have all other work per‐
formed by a servicing dealer.

STIHL recommends that you have servicing and
repair work carried out exclusively by an author‐
ized STIHL servicing dealer. STIHL dealers are
regularly given the opportunity to attend training
courses and are supplied with the necessary
technical information.

Only use high-quality replacement parts in order
to avoid the risk of accidents and damage to the
machine. If you have any questions in this
respect, consult a servicing dealer.

STIHL recommends the use of original STIHL
replacement parts. They are specifically
designed to match your model and meet your
performance requirements.

To reduce the risk of injury, always shut off the
engine before carrying out any maintenance or
repairs or cleaning the machine. – Exception:
Carburetor and idle speed adjustments.

Do not turn the engine over on the starter with
the spark plug boot or spark plug removed
unless the slide control / stop switch is on STOP
or 0 since there is otherwise a risk of fire from
uncontained sparking.

To reduce the risk of fire, do not service or store
your machine near open flames.

Check the fuel filler cap for leaks at regular inter‐
vals.

Use only a spark plug of the type approved by
STIHL and make sure it is in good condition –
see "Specifications".

Inspect the ignition lead (insulation in good con‐
dition, secure connection).

Check the condition of the muffler.

To reduce the risk of fire and damage to hearing,
do not operate your machine if the muffler is
damaged or missing. –

Do not touch a hot muffler since burn injury will
result.

2.12 Symbols on Deflectors

An arrow on the deflector shows the correct
direction of rotation of the cutting attachments.

Some of the following symbols are applied to the
outside of the deflector to indicate the approved
combination of cutting tool and deflector.

Use deflector in combination with
mowing heads only. Do not use metal
cutting attachments.

Do not use deflector with brush kni‐
ves or circular saw blades.

Do not use deflector with mowing
heads.

Use deflector in combination with
grass cutting blades only.

2.13 Shoulder strap

► Use a shoulder strap.
► With the engine running, attach the machine to

the shoulder strap.

Grass cutting blades must always be used in
combination with a shoulder strap.

8 0458-233-8321-G

000BA015 KN

002BA049 KN

002BA135 KN

2 Safety Precautions and Working Techniques English

2.14 Mowing Head with Nylon Line

If one of the wear limit marks on the PolyCut
mowing head is worn through (arrow): Do not
continue using the mowing head. Install a new
one. There is otherwise a risk of injury from
thrown parts of the head.

It is important to follow the maintenance instruc‐
tions for the PolyCut mowing head.

The PolyCut can also be equipped with mowing
line in place of the polymer blades.

The mowing head comes with instruction leaflets.
Equip the mowing head with polymers blades or
nylon line as described in the instruction leaflets.

Nylon line achieves a soft cut for edging and
trimming around trees, fence posts, etc. – less
risk of damaging tree bark.

The mowing head comes with an instruction leaf‐
let. Refill the mowing head with nylon line as
described in the instruction leaflet.

WARNING

To reduce the risk of serious injury, never use
wire or metal-reinforced line in place of the nylon
line.

2.15 STIHL Polycut Mowing Head with Polymer Blades

For mowing unobstructed edges of meadows
(without posts, fences, trees or similar obsta‐
cles).

Check the wear limit marks!

WARNING

Never use wire in place of the nylon mowing line
– risk of injury.

2.16 Risk of Kickout (Blade Thrust) with Metal Cutting Attachments

WARNING

When using metal cutting attach‐
ments there is a risk of kickout when
the rotating blade comes into contact
with a solid object such as a tree
trunk, branch, tree stump, rock or
similar. The machine is thrown to the
right or to the rear – opposite to the
attachment's direction of rotation.

0458-233-8321-G 9

000BA020 KN

1

2

4

6

9

11

12

13

14

16

17

18

19

17

18

19

21

22

22

21

20

22

3

8

15

5

0000078689_005

7

10

English 3 Approved Combinations of Cutting Attachment, Deflector, Handle and Harness

The risk of kickout is greatest when the black
area of the rotating cutting attachment comes
into contact with a solid object.

Use for grass and weeds only – sweep the
brushcutter in an arc like a scythe.

WARNING

2.17 Grass Cutting Blade

Improper use may damage the grass cutting
blade – risk of injury from thrown parts.

Resharpen the grass cutting blade according to
instructions when it has dulled noticeably.

3 Approved Combinations of Cutting Attachment, Deflector, Han‐

dle and Harness

Cutting attachment Deflector Handle Carrying strap

10 0458-233-8321-G

1

3

2

5

7

6

4

233BA025 KN

4 Mounting the Bike Handle English

3.1 Permissible combinations

Choose the correct combination from the table
depending on the cutting tool!

WARNING

3.5 Shoulder straps

20 Shoulder strap can be used

21 Shoulder strap must be used

22 Full harness can be used

For safety reasons only the cutting attachments,
deflector, handle and harness versions within
one line of the table may be combined with one
another. No other combinations are permitted
because of the risk of accidents!

3.2 Cutting attachments

3.2.1 Mowing heads

1 STIHL SuperCut 20‑2

2 STIHL AutoCut C 25-2

3 STIHL AutoCut 25-2 / AutoCut 27-2

4 STIHL AutoCut C 26-2

5 STIHL FixCut 31-2

6 STIHL TrimCut 31-2

7 STIHL TrimCut 32-2

8 STIHL DuroCut 20-2

9 STIHL PolyCut 20-3

10 STIHL PolyCut 28-2

3.2.2 Metal cutting tools

11 Grass cutting blade 230-2

(230 mm dia.)

12 Grass cutting blade 230-4

(230 mm dia.)

13 Grass cutting blade 230-8

(230 mm dia.)

WARNING

Grass cutting blades of materials other than
metal must not be used.

4 Mounting the Bike Handle

4.1 Mounting the Handlebar

► Position the clamp (1) and handlebar sup‐

port (2) on the shaft (3)

► Place the handlebar (4) in the handlebar sup‐

port – the rubber handle (5) must be on the left

(viewing direction from engine to handlebar)
► Place the clamp (6) on the handlebar support
► Insert the screws (7) through the holes in the

parts and screw them into the clamp (6) as far

as they will go

3.3 Deflectors

14 Deflector for mowing heads

15 Deflector for metal cutting attachments

3.4 Handles

16 Loop handle

17 Loop handle with

18 Barrier bar

19 Bike handle

0458-233-8321-G 11