Stihl GS 461 User manual

{
STIHL GS 461 Instruction Manual
Notice d’emploi

GInstruction Manual
1 - 34
FNotice d’emploi
35 - 71

Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2018 0458-761-8221-A. VA4.D18. 0000006307_013_GB
GS 461
English
1
{This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.
Contents
Dear Customer,
Thank you for choosing a quality
engineered STIHL product.
It has been built using modern
production techniques and
comprehensive quality assurance.
Every effort has been made to ensure
your satisfaction 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
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 2
Sample Applications 9
Cutting Attachment 11
Mount Guide Bar and Diamond
Abrasive Chain 11
Tension Diamond Abrasive Chain 13
Check Tension of Diamond
Abrasive Chain 13
Fuel 14
Fueling 15
Starting / Stopping the Engine 16
Operating Instructions 19
Air Filter System 20
Remove Air Filter 20
Cleaning the Air Filter 20
Engine Management 21
Adjusting the Carburetor 21
Spark Arresting Screen in Muffler 22
Spark Plug 23
Storing the Machine 24
Taking Care of the Guide Bar 24
Checking and Replacing the Chain
Sprocket 25
Maintain and Sharpen Diamond
Abrasive Chain 26
Maintenance and Care 27
Main Parts 29
Specifications 31
Maintenance and Repairs 31
Disposal 32
STIHL Limited Emission Control
Warranty Statement 32

GS 461
English
2
Pictograms
Pictograms that appear on the machine
are explained in this Instruction Manual.
Depending on the machine and
equipment version, the following
pictograms may appear on the machine.
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.
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 manual.
Comply with national safety regulations
issued, e.g. by employers' liability
insurance associations, social security
institutions, occupational safety and
health authorities or other organizations.
Anyone using the power tool for the first
time: Have your dealer or other
experienced user show you how to
operate your machine – or attend a
special course in its operation.
Minors are not allowed to work with the
power tool – except adolescents above
16years of age, who were instructed
under supervision.
Children, animals and bystanders must
remain at a distance.
When the power tool is not in use, put it
down so that it does not endanger
others. The machine must be secured
against unauthorized access.
Guide to Using this Manual
Fuel tank; fuel mixture of
gasoline and engine oil
Direction of chain travel
Tension diamond abra-
sive chain
Actuate decompression
valve
Water connection, shut-
off cock
Safety Precautions and
Working Techniques
Because the chain of a
concrete cutter runs at
very high speeds, spe-
cial safety precautions
must be observed to
reduce the risk of per-
sonal injury.
It is important you read
and understand the
Instruction Manual before
first use and keep the
manual in a safe place for
future reference. Non-
observance of the
Instruction Manual may
result in serious or even
fatal injury.

GS 461
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3
The user is responsible for avoiding
injury to third parties or damage to their
property.
Hand-over or lend the engine-driven
device to those persons only, who are
familiar with this model and its handling
– always pass the instruction manual to
them as well.
The use of noise emitting machines may
be restricted to certain times by national
or local regulations.
The machine may only be operated by
people who are fit, in good physical
health and in good mental condition.
If you have any condition that might be
aggravated by strenuous work, check
with your doctor before operating a
power tool.
If you have a pacemaker: The ignition
system of this machine produces an
electromagnetic field of very low
intensity. An effect on individual
pacemaker types cannot be excluded
entirely. STIHL recommends that you
consult your doctor and the
manufacturer of your pacemaker in
order to avoid health hazards.
Never work with the machine while
under the influence of alcohol,
medication or drugs capable of impairing
your reaction speed.
Postpone the work if the weather is bad
(rain, snow, ice, wind) – higher risk of
accidents!
The machine may only be used for
cutting
The machine must not be used for any
other purposes – risk of accidents!
It is not suitable for cutting wood or
wooden objects.
Asbestos dust is extremely toxic - the
machine must therefore never be used
to cut asbestos!
Only use tools, guide bars, diamond
abrasive chains or accessories that
have been approved by STIHL for this
machine or which are technically
equivalent. If you have any questions in
this respect, consult a servicing dealer.
Use only high quality tools and
accessories. Otherwise there may be a
risk of accidents or damage to the
machine.
STIHL recommends the use of genuine
STIHL guide bars, diamond abrasive
chains, chain sprockets and
accessories. They are specifically
designed to match your model and meet
your performance requirements.
Do not modify the device – otherwise the
safety may be endangered. STIHL
excludes all liability for personal injury
and damage to property caused while
using unauthorized attachments.
Do not use high-pressure cleaners to
clean the machine. The hard water jet
can damage parts of the machine.
Clothing and equipment
Wear proper protective clothing and
equipment.
Do not wear clothing that could become
trapped in moving parts of the machine
– no scarves, no neckties, no jewelry.
Tie up and confine long hair.
WARNING
Wear a face shield and make sure it fits
correctly. A face mask alone is not
sufficient to protect the eyes.
Wear "personal" hearing protection –
e.g., ear defenders.
Wear a hard hat wherever there is any
risk of falling objects.
While working, dust (for example,
crystalline material from the object to be
parted-off), vapor and smoke may be
produced – danger for health!
Always wear a dust mask if dust is
generated.
Clothing must be sturdy
and snug-fitting, but allow
complete freedom of
movement. Wear snug
fitting clothing – an over-
all and jacket
combination, do not wear
a work coat.
Wear safety boots with
steel toe caps and non-
slip soles.
To reduce the risk of eye
injuries, wear tight-fitting
safety goggles conform-
ing to standard EN166.
Make sure that the safety
goggles fit correctly.

GS 461
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4
If fumes or smoke are anticipated (e.g.,
when cutting composite materials), wear
respiratory protection.
STIHL can supply a comprehensive
range of personal protective clothing
and equipment.
Transporting the machine
Always stop the engine and attach the
chain scabbard.
Carry the machine only by the top
handle – guide bar towards the rear –
with the hot muffler facing away from the
body.
Do not touch hot device parts, in
particular the muffler surface – risk of
burns!
In vehicles: Properly secure the machine
to prevent turnover, fuel spillage and
damage.
Refuelling
Switch off the engine before refuelling.
Never refuel the machine while the
engine is still hot – the fuel may spill over
– risk of fire!
Open the fuel filler cap carefully so that
any excess pressure is relieved
gradually and fuel does not splash out.
The machine may only be refuelled in a
well ventilated place. If fuel has been
spilled, clean immediately the engine-
driven device – prevent your clothes
from being contaminated with fuel,
otherwise change clothes at once.
Dust may collect on the engine unit,
especially around the carburetor. If dust
gets mixed with fuel – risk of fire!
Remove the dust from the engine unit
regularly.
Bayonet filler cap
Never use a tool to open or close the
bayonet filler cap. The cap can be
damaged and fuel may escape.
Secure the bayonet filler cap tightly after
refueling.
Diamond abrasive chain
The diamond abrasive chain, guide bar
and chain sprocket must match each
other and your concrete cutter.
Use only approved diamond abrasive
chains. If unauthorized chains are used,
aggressive cutting cannot be ruled out.
This may lead to uncontrolled and
exceedingly dangerous reaction forces
(kickback) in the machine – risk of fatal
injuries!
Only use diamond abrasive chain for the
specified materials, observe diamond
abrasive chain codes.
Always cut with water.
Before fitting used diamond abrasive
chains, check that they are not cracked,
chipped, check also that there are no
damaged or missing segments, signs of
overheating (discoloration).
Never use diamond abrasive chains that
are cracked or have chipped segments.
Contact your servicing dealer.
Before starting
Check that concrete cutter is properly
assembled and in good condition – refer
to appropriate chapters in the Instruction
Manual:
–Check the fuel system for leaks,
especially the visible parts, e.g.,
filler 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 servicing
dealer before using it.
–functional, front hand guard
–Check chain sprocket
–Sprocket nose moves easily
–Correctly mounted guide bar
Wear sturdy protective
gloves made of a resist-
ant material (e.g.
leather).
Petrol is an extremely
flammable fuel – keep
clear of naked flames and
fire – do not spill any fuel
– no smoking.
Look out for leaks! Never
start the engine if fuel has
been spilled or is leaking
– Fatal burns may result!

GS 461
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5
–The diamond abrasive chain must
be suitable for the material to be cut.
It must be in good condition and
fitted correctly (direction of running).
–Correctly tensioned diamond
abrasive chain
–Both the accelerator lever and its
locking to move smoothly – the
accelerator lever has automatically
to return to its idle run position.
–Master control lever can be moved
to STOP or 0
–Check that the spark plug boot is
secure. A loose boot can lead to
flying sparks which may ignite the
escaping fuel/air mixture – risk of
fire!
–Never attempt to modify the controls
or safety devices in any way
–Keep the handles dry and clean,
free from oil and dirt – important for
safe control of the concrete cutter
The concrete cutter should only be used
if it is in full working order – risk of
accident!
Starting the engine
Move at least 3meters away from the
place at which the machine was refueled
and never start the machine in enclosed
spaces.
The machine may only be used on level
ground. Ensure a firm and secure
footing and hold the machine firmly. The
diamond abrasive chain must not touch
any objects or the ground and must not
be in the cut, because it may begin to
rotate when the machine is started.
The engine-driven device is operated by
a single person only – do not allow any
person to stay within the working area –
nor with starting.
Do not drop-start the engine – start as
described in the Instruction Manual.
Before starting, open the shut-off valve
completely and ensure a supply of water
to the diamond abrasive chain – do not
allow diamond abrasive chain to run dry.
Holding and controlling the machine
Always hold the machine firmly with both
hands: Right hand on the rear handle –
even if you are left-handed. To ensure
reliable control, wrap your thumbs tightly
around the handlebar and handle.
The object to be parted-off has to be
firmly supported. Always guide the
device towards the workpiece – never in
reverse.
During operation
Ensure you always have a firm and safe
footing.
In the event of impending danger or in
an emergency, switch off the engine
immediately by moving the master
control lever to STOPor0.
The machine is operated by only one
person. There should not be any other
person within the working area.
Use extreme caution with openings,
recesses, etc., someone could be
standing behind them – look
beforehand.
Never let the machine run unattended.
When the engine is running: The
diamond abrasive chain continues to run
for some time after the throttle trigger
has been released – Risk of injury due to
coasting effect!
Beware of slipping on ice, water, snow
or uneven ground!
Don not work while standing on a ladder
– not at unstable places – not over your
shoulder height – not with one hand only
– risk of accident!
Keep clear the working area – bear in
mind obstacles, holes and pitches.
Never work alone – stay always in
earshot to other persons, who can
render first aid in case of emergency.
More care and attention than usual are
required when wearing ear protection –
warning sounds (shouts, alarms, etc.)
cannot be heard properly.
Take a break in good time to avoid
tiredness or exhaustion – risk of
accidents!
Keep easily combustible materials away
from hot exhaust gases and hot mufflers
– risk of fire! Mufflers with catalytic
converters can become especially hot.
2411BA046 KN

GS 461
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6
Ensure proper ventilation when working
in trenches, hollows or other confined
areas. Toxic fumes can kill!
With sick feeling, headache, eye defect
(for example, shrinking field of vision),
hearing impairment, dizziness, fading
powers of concentration, stop working
immediately – such symptoms may be
caused, among others, by high exhaust
gas concentration – risk of accident!
No smoking when working with or near
the machine - risk of fire! Combustible
fuel vapour may escape from the fuel
system.
Examine the diamond abrasive chain
periodically at short intervals, check that
they are not cracked, chipped, check
also that there are no damaged or
missing segments, signs of overheating
(discoloration).
Never use diamond abrasive chains that
are cracked or have chipped segments.
Contact your servicing dealer.
In the event of noticeable changes in
cutting behavior (e.g., increased
vibration, reduced cutting performance),
stop work and eliminate the causes of
the changes.
–Switch off the engine and wait until
the diamond abrasive chain is
stationary
–Check condition and correct tension
of diamond abrasive chain
–Check sharpness
Never touch the diamond abrasive chain
when the motor is running. If the
diamond abrasive chain becomes
jammed by an object, switch off the
engine immediately before attempting to
remove the object – risk of injury!
To change the diamond abrasive chain,
switch off the engine – risk of injury!
If the machine 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 – refer also to the
section "Before starting". Check the fuel
system for leaks and make sure the
safety devices are working properly.
Never continue using a power tool that is
not in perfect working order. In case of
doubt, have the unit checked by your
servicing dealer.
Check for correct idling, so that the
diamond abrasive chain stops moving
when the throttle trigger is released.
Check and/or correct the idle setting
regularly. Have the machine repaired by
a STIHL servicing dealer if the diamond
abrasive chain continues to run
nevertheless.
Reactive forces
The most frequently occurring reactive
forces are pull-in and pushback.
Pull-in(A)
When the diamond abrasive chain on
the bottom of the guide bar –
overbucking – is jammed or encounters
a solid object, the concrete cutter may
suddenly be drawn forward to the
workpiece.
Pushback(B)
When the diamond abrasive chain on
the top of the guide bar – underbucking
– is jammed or encounters a solid object,
the concrete cutter may suddenly be
driven straight back toward the operator.
Your power tool produces
toxic exhaust fumes as
soon as the engine is
running. These gases
may be colorless and
odorless and may contain
unburnt hydrocarbons
and benzene. Never work
with the engine-driven
device in closed or poorly
vented rooms – even not
with devices equipped
with a catalyst.
2411BA001 KN
A
2411BA002 KN
B

GS 461
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–Do not allow the guide bar to
become jammed
–Always be aware that the object to
be cut may move and other factors
may cause the cut to close and jam
the diamond abrasive chain
–The object to be cut must be
secured and supported so that the
cut remains open during and after
cutting
–Do not twist the guide bar in the cut
Working – parting-off grinding
Ensure sufficient water supply to
diamond abrasive chain – do not allow
diamond abrasive chain to run dry.
Always wet cut – regardless of the
material to be cut.
The diamond abrasive chain must be
guided straight in the cut, without
wedging. Never exert lateral pressure on
the diamond abrasive chain.
Do not use for lateral grinding or
scrubbing.
Do not use the starting throttle position
for cutting. Engine speed cannot be
controlled with the throttle trigger in this
position.
Check the work area. Avoid danger due
to damage to pipes and electric power
lines.
The machine must not be used in the
vicinity of flammable substances and
combustible gases.
Do not cut into pipes, metal tanks or
other containers if you are not sure that
they do not contain any volatile or
inflammable substances.
Never leave the machine unattended
with the engine running. Stop the engine
before leaving the machine unattended
(e.g. for breaks).
Work calmly and carefully – in daylight
conditions and only when visibility is
good. Do not endanger others – stay
alert at all times.
Make certain that all parts of your body
are well clear of the extended range of
travel of the diamond abrasive chain.
Only pull concrete cutter out of the
object being cut with the diamond
abrasive chain running.
Only use concrete cutter for cutting – not
for prying or shoveling away objects.
Always decide the cutting direction
before positioning the concrete cutter.
Do not change the cutting direction.
Never push or hit with the device into the
cutting gap – do not let the parting-off
grinder fall into the cutting depth – risk of
breakage!
If cutting performance begins to
deteriorate, check the sharpness of the
diamond abrasive chain, resharpen as
needed. To do this, briefly cut through
abrasive material, e.g., sandstone,
aerated concrete or asphalt.
When working at heights:
–Always use a lift bucket
–Never use the machine while
standing on a ladder
–Never use the machine in unsteady
locations
–Never cut above shoulder height
–Never use the machine with one
hand
Begin cutting with the concrete cutter at
full throttle.
At the end of the cut, the concrete cutter
is no longer supported by the cutting
attachment in the cut. The machine's
weight must be borne by the user – risk
of loss of control!
Keep water and sludge away from alive
electrical cables – risk of electric shock!
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.
002BA146 KN
2411BA003 KN

GS 461
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8
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 circulation (symptoms:
frequently cold fingers, tingling
sensations).
–Low outside temperatures.
–The force with which the handles
are held (a tight grip restricts
circulation).
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.
Maintenance and repairs
The machine must be serviced regularly.
Do not attempt any maintenance or
repair work not described in the
Instruction Manual. All other work should
be carried out by a servicing dealer.
STIHL recommends that maintenance
and repair work be carried out only by
authorized STIHL dealers. STIHL
dealers receive regular training and are
supplied with technical information.
Use only high-quality spare parts.
Otherwise, there may be a risk of
accidents or damage to the machine.
Contact a servicing dealer if in doubt.
STIHL recommends the use of genuine
STIHL spare parts. Such parts have
been optimized for the machine and the
user's requirements.
Before starting any maintenance or
repair work and before cleaning the
machine, always stop the engine – risk
of injury! – Exception: adjustment of
carburetor and idle speed.
To reduce the risk of fire due to ignition
outside the cylinder, move the slide
control to STOP or 0 before turning the
engine over on the starter with the spark
plug boot removed or the spark plug
unscrewed.
Do not service or store the machine near
a naked flame – risk of fire due to the
fuel.
Check fuel cap regularly for tightness.
Use only spark plugs that are in perfect
condition and have been approved by
STIHL – see "Specifications".
Inspect ignition lead (insulation in good
condition, secure connection).
Check that the muffler is in perfect
working condition.
Do not use the machine if the muffler is
damaged or missing – risk of fire! –
Hearing damage!
Never touch a hot muffler – risk of burns!
The condition of the antivibration
elements influences vibration behavior –
inspect antivibration elements
periodically.
Switch off the engine
–to check the chain tension
–to retension the chain
–to change chains
–for remedying malfunctions
Maintenance, replacement, or repair of
the emission control devices and
systems may be performed by any
nonroad engine repair establishment or
individual. However, if you make a
warranty claim for a component which
has not been serviced or maintained
properly or if nonapproved replacement
parts were used, STIHL may deny
coverage.
For any maintenance please refer to the
maintenance chart and to the warranty
statement near the end of the instruction
manual.

GS 461
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9
The water introduced is used to cool the
diamond abrasive chain and rinse the
cutting attachment, and for binding dust.
After finishing work, run the concrete
cutter for a few seconds with water and
at operating speed to rinse the cutting
attachment.
If the water pressure or water volume is
too low, this leads to significantly
increased wear and irreparable damage
to the cutting attachment – danger of
breakage!
Objects to be cut
–Must be fully supported
–Must be secured so it cannot roll or
slip off
–Must be prevented from vibrating
Severed parts
With openings, recesses, etc., the
sequence of the cuts is important.
Always make the last cut so that the
diamond abrasive chain does not
become jammed and so that the
operator is not endangered by the
severed or separated part.
If necessary, use wedges and if
necessary, leave small ridges that hold
the part that is to be separated in
position. Break these ridges later.
Before finally separating the part,
determine:
–how heavy the part is
–how it can move after separation
–whether it is under tension
When breaking out the part, do not
endanger assistants.
Plunge-cutting
Begin cutting with the concrete cutter at
full throttle.
1. Apply the lower portion of the guide
bar nose
2. Swing slowly into the plunge-cutting
position
3. Make the plunge cut very carefully
When making the plunge cut into
existing, narrower joints, proceed with
extreme care.
Cut in several passes
NMark cutting line(A)
NWork along the cutting line. When
making corrections, do not tilt the
diamond abrasive chain, always
reposition it afresh
Sample Applications
Use diamond abrasive
chain only with water.
Connect concrete cutter
to water supply network
(min. 1.5bar).
3.
2411BA004 KN
1.
2.
A
2411BA005 KN
2411BA006 KN

GS 461
English
10
Cutting round and hollow bodies
NSecure pipes, round bodies, etc.
against rolling away
NMark a cutting line - when
determining the cutting line, avoid
reinforcement, especially in the
direction of the severing cut
NMake the plunge cut very carefully
NFeed with full cutting depth along
the cutting line – for small
corrections of direction, do not tilt
the diamond abrasive chain, but
always position it anew instead – if
necessary, use wedges and if
necessary, leave small ridges that
hold the part that is to be separated
in position. Break these ridges later
Shaping pipe
NSecure pipes, round bodies, etc.
against rolling away
NMark a cutting line - when
determining the cutting line, avoid
reinforcement, especially in the
direction of the severing cut
DANGER
Manual cutting along this line requires
particular caution and precision.
NCut into pipes, round bodies, etc. in
the area at the ends of the cutting
line, so that the material does not
break away
NMake the plunge cut very carefully
at the apex and cut outward on both
sides - feed with full cutting depth
along the cutting line – for small
corrections of direction, do not tilt
the diamond abrasive chain, but
always position it anew instead – if
necessary, use wedges and if
necessary, leave small ridges that
hold the part that is to be separated
in position. Break these ridges later
2411BA007 KN
2411BA008 KN

GS 461
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11
Diamond abrasive chain, guide bar and
chain sprocket make up the cutting
attachment.
The cutting attachment that is supplied
has been optimized for the concrete
cutter.
–The pitch(t) of the diamond
abrasive chain(1), chain sprocket
and sprocket nose of the Rollomatic
guide bar must match
–The drive link gauge(2) of the
diamond abrasive chain(1) must be
matched to the groove width of the
guide bar(3)
When pairing components that are not
compatible with each other, the cutting
attachment may become damaged
beyond repair after only a short period of
operation.
Diamond abrasive chain
The correct use of the STIHL diamond
abrasive chain ensures economical use
and avoids accelerated wear.
The STIHL diamond abrasive chain is
suitable for cutting the following
materials:
–Concrete
–Reinforced concrete
–General blocks
–Masonry
–Stone pipes
–Abrasive stone*, e.g. asphalt and
bricks (sandstone)
–Hard stone*, granite*
–ductile cast iron pipes*
*) Restrictions on power and service life
are possible
Do not cut any other materials – risk of
accident!
Chain scabbard
The product contents includes a chain
scabbard that is suitable for the bar and
chain.
Removing the chain sprocket cover
NUnscrew nuts(1) from the studs –
nuts are fastened to the chain
sprocket cover so that they are
secured against loss
NRemove chain sprocket cover(2)
NTurn the screw(3) to the left until
the tensioner slide(4) butts against
the left end of the housing slot
Cutting Attachment
2411BA009 KN
1
2
3
a
t = a : 2
Mount Guide Bar and
Diamond Abrasive Chain
11
2411BA011 KN
2
4
2411BA012 KN
3

GS 461
English
12
Fit diamond abrasive chain
NFit the diamond abrasive chain
starting at the nose of the guide bar
NPosition the guide bar over the
bolts(1) – align drive links so that
the position lines up with the symbol
(arrow)
WARNING
If the drive links are not directionally
aligned one behind the other correctly,
the diamond abrasive chain and chain
sprocket will be damaged beyond repair.
NPosition the right locating hole(2)
over the peg of the tensioner slide –
simultaneously place the diamond
abrasive chain over the sprocket
wheel(3)
NTurn screw(4) to the right until there
is very little diamond abrasive chain
sag on the underside of the bar and
the lugs of the drive links engage in
the bar groove
NRefit the chain sprocket cover – and
then screw on the nut by hand until
it is fingertight
NGo to chapter "Tensioning the
diamond abrasive chain"
Moving the guide bar
Only move the guide bar if the diamond
abrasive chain cannot be tensioned
properly.
NRemoving the chain sprocket cover
NRemove guide bar with diamond
abrasive chain
NFit the diamond abrasive chain
starting at the nose of the guide bar
NPosition the guide bar over the
bolts(1) – align drive links so that
the position lines up with the symbol
(arrow)
WARNING
If the drive links are not directionally
aligned one behind the other correctly,
the diamond abrasive chain and chain
sprocket will be damaged beyond repair.
NPosition the left locating hole(5)
over the peg of the tensioner slide –
simultaneously place the diamond
abrasive chain over the sprocket
wheel(3)
NTurn screw(4) to the right until there
is very little diamond abrasive chain
sag on the underside of the bar and
the lugs of the drive links engage in
the bar groove
NRefit the chain sprocket cover – and
then screw on the nuts by hand until
they are fingertight
NGo to chapter "Tensioning the
diamond abrasive chain"
2411BA013 KN
4
11
2411BA0014 KN
4
11
2411BA049 KN

GS 461
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13
For retensioning during operation:
NSwitch off the engine
NPut on protective gloves
NLoosen nuts
NRaise the guide bar at the nose
NUse the screwdriver to turn the
screw(1) to the right until the
distance(a)=approx.5mm
If the distance(a)=approx.5mm
cannot be set due to an elongated
diamond abrasive chain, move guide bar
– see installing "guide bar and diamond
abrasive chain".
NRaise the guide bar further and
tighten the nuts securely
NCheck tension of diamond abrasive
chain – diamond abrasive chain can
be pulled across the guide bar by
hand
A new diamond abrasive chain must be
retensioned more frequently than one
that has been in use already for an
extended period.
NCheck chain tension frequently –
see "Operating Instructions"
NSwitch off the engine
NDiamond abrasive chain can sag a
maximum of a=15mm
NRetension diamond abrasive chain
if necessary – see "Tensioning the
diamond abrasive chain".
If the diamond abrasive chain sags too
much, this leads to significantly
increased wear of the cutting
attachment.
A new diamond abrasive chain must be
retensioned more frequently than one
that has been in use already for an
extended period.
NCheck chain tension frequently –
see "Operating Instructions"
Tension Diamond Abrasive
Chain
1
2411BA0015 KN
2411BA0045 KN
Check Tension of Diamond
Abrasive Chain
a
2411BA016 KN

GS 461
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14
This engine is certified to operate on
unleaded gasoline and with the mix ratio
50:1.
Your engine requires a mixture of high-
quality premium gasoline and high-
quality two-stroke air-cooled engine oil.
Use premium branded unleaded
gasoline with a minimum octane rating
of 89 (R+M)/2.
Note: Models equipped with a catalytic
converter require unleaded gasoline. A
few tankfuls of leaded gasoline can
reduce the efficiency of the catalytic
converter by more than 50%.
Fuel with a lower octane rating may
result in preignition (causing "pinging")
which is accompanied by an increase in
engine temperature. This, in turn,
increases the risk of the 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 as
well. This could cause running problems
or even damage the engine. For this
reason it is essential that you use only
high-quality fuels!
Fuels with different percentages of
ethanol are being offered. Ethanol can
affect the running behaviour of the
engine and increase the risk of lean
seizure.
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
with a manually adjustable carburetor
and should not be used in such engines.
Engines equipped with M-Tronic can be
run on gasoline with an ethanol content
of up to 25% (E25).
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke air-
cooled engine oils for mixing.
We recommend STIHL 50:1 two-stroke
engine oil since it is specially formulated
for use in STIHL engines.
To ensure the maximum performance of
your STIHL engine, use a high quality 2-
cycle 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.
Do not use BIA or TCW (two-stroke
water cooled) mix oils!
Use only STIHL 50:1 heavy-duty engine
oil or an equivalent quality two-stroke
engine oil for the fuel mix in models
equipped with a catalytic converter.
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapour.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The fuel tank and the canister in which
fuel mix is stored should be cleaned
from time to time.
Fuel mix ratio
Only mix sufficient fuel for a few days
work, not to exceed 30days of storage.
Store in approved safety fuel-canisters
only. When mixing, pour oil into the
canister first, and then add gasoline.
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
Fuel
Examples
Gasoline Oil (STIHL 50:1 or equiva-
lent high-quality oils)
liters liters (ml)
1 0.02 (20)
5 0.10 (100)
10 0.20 (200)
15 0.30 (300)
20 0.40 (400)
25 0.50 (500)

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Preparations
NBefore fueling, clean the filler cap
and the area around it to ensure that
no dirt falls into the tank.
NPosition the machine so that the
tank cap faces up.
WARNING
Never use a tool to open the bayonet-
type fuel cap. This may damage the cap
and cause fuel leakage.
Open the cap.
NPress the cap down as far as stop,
turn it counterclockwise (about 1/8
turn) and remove.
Filling Up with Fuel
Take care not to spill fuel while fueling
and do not overfill the tank. STIHL
recommends you use the STIHL filler
nozzle for fuel (special accessory).
Closing the Cap
NPlace the cap on the tank opening
and turn it until it slips into position.
NPress the cap down by hand as far
as stop and turn it clockwise (about
1/8 turn) until it engages.
Checking Security of Cap
NGrip the cap – it is properly locked if
it cannot be pulled off and the marks
(arrows) on the cap and fuel tank
are in line.
If the cap can be pulled off or the marks
are not in line, refit it – see sections on
“Closing the Cap” and “Checking
Security of Cap”.
Change the Fuel Pickup Body Every
Year
NDrain the fuel tank.
NUse a hook to pull the fuel pickup
body out of the tank and take it off
the hose.
NPush the new pickup body into the
hose.
NPlace the pickup body in the tank.
Fueling
2411BA054 KN
2.
1.
2411BA055 KN
2.
1.
2411BA056 KN
2411BA019 KN

GS 461
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The four positions of the Master Control
lever
STOP or 0 – engine off – ignition is
switched off
RunF – engine is running or can start
Warm startn – this position is for
starting the warm engine
Cold startl – this position is for starting
the cold engine
Adjusting the Master Control lever
The throttle trigger lockout and throttle
trigger must be pressed simultaneously
to adjust the Master Control lever from
runF to cold startl.
To set the Master Control lever to warm
startn, first set it to cold startl, then
push the Master Control lever into the
warm startn position.
Changing to warm startn is only
possible from the cold startl position.
When the throttle trigger is squeezed,
the Master Control lever returns from
warm startn to runF.
To switch off the engine, set the master
control lever to STOP or 0.
Position cold startl
–If the engine is cold
–If the engine stalls during opening of
throttle after starting
–If the fuel tank has run empty
(engine stalled out)
Position warm startn
–If engine is warm (once the engine
has been running for approx. one
minute)
–When the engine has fired for the
first time
–After ventilation of the combustion
chamber, if the engine was flooded
Connect concrete cutter to water supply
network
NConnect concrete cutter to water
supply network (min.1.5bar)
NBefore starting, open shut-off valve
(arrow) completely
Hold concrete cutter
There are two ways to hold the concrete
cutter during starting.
Starting / Stopping the
Engine
STOP
0
001BA140 KN
2411BA025 KN

GS 461
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17
On the ground
NPlace the concrete cutter securely
on the ground – assume a steady
stance- the diamond abrasive chain
must not touch any objects or the
ground
NPress the concrete cutter firmly
against the ground, holding the front
handle with your left hand, thumb
wrapped round the handle
NPlace your right foot into the rear
handle
Between the knees or thighs
NClamp the rear handle between the
knees or thighs
NGrip the handlebar firmly with the
left hand – thumb wrapped around
the handlebar
Starting
NWith the right hand, pull the starter
grip slowly until you feel it engage –
and then give it a brisk strong pull –
simultaneously press down on the
handlebar – do not pull the starter
rope out all the way – risk of
breakage! Do not let the starter grip
snap back – guide it vertically back
into the housing so that the starter
rope can rewind properly
Starting the concrete cutter
Before starting, open the shut-off valve
completely and ensure a supply of water
to the diamond abrasive chain – do not
allow diamond abrasive chain to run dry.
2411BA020 KN
0001BA021 KN
2411BA022 KN

GS 461
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18
Decompression valve
NPress the button, the
decompression valve will be
opened
The decompression valve is closed
automatically when the engine fires for
the first time. For this reason, press the
button again before each additional
starting attempt.
DANGER
There must not be anyone within the
swivel range of the concrete cutter.
NSimultaneously press the throttle
trigger lockout(2) and throttle
trigger(3) – set the master control
lever
Position cold startl
–If engine is cold (even if the engine
has stalled during opening of
throttle after starting)
Position warm startn
–If engine is warm (once the engine
has been running for approx. one
minute)
NHold and start the concrete cutter
When the engine has turned over for the
first time
NMove the Master Control lever(1) to
the position warm startn
NPress the button on the
decompression valve
NHold and continue cranking the
concrete cutter
Once the engine is running
NBlip the throttle trigger(2); the
Master Control lever(1) jumps to
run F and the engine begins to idle
The concrete cutter is now ready for use.
At very low temperatures
NLet the engine warm up briefly with
the throttle slightly open
2411BA023 KN
2
1
2411BA024 KN
STOP
1
2411BA026 KN
STOP
2
1
2411BA027 KN
STOP