Stihl MS 151 TC User manual

STIHL MS 151 TC
Instruction Manual2 - 32

Contents
1 Guide to Using this Manual.........................2
2 Safety Precautions......................................3
3 Reactive Forces.......................................... 8
4 Working Techniques................................... 9
5 Cutting Attachment................................... 10
6 Mounting the Bar and Chain..................... 11
7 Tensioning the Saw Chain (side chain ten‐
sioner)....................................................... 12
8 Checking Chain Tension...........................12
9 Fuel........................................................... 12
10 Fueling...................................................... 13
11 Chain Lubricant.........................................15
12 Filling Chain Oil Tank................................16
13 Checking Chain Lubrication...................... 16
14 Chain Brake.............................................. 16
15 Starting / Stopping the Engine.................. 17
16 Operating Instructions...............................20
17 Taking Care of the Guide Bar................... 21
18 Cleaning the Air Filter............................... 21
19 Adjusting the Carburetor........................... 21
20 Spark Plug................................................ 22
21 Storing the Machine.................................. 23
22 Checking the Chain Sprocket................... 23
23 Maintaining and Sharpening the Saw Chain
.................................................................. 24
24 Maintenance and Care..............................28
25 Main Parts.................................................30
26 Specifications............................................30
27 Special Accessories..................................31
28 Ordering Spare Parts................................ 31
29 Maintenance and Repairs......................... 31
30 Disposal.................................................... 32
31 EC Declaration of Conformity................... 32
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
This Instruction Manual refers to a STIHL chain
saw, also called a machine in this Instruction
Manual.
1.1 Pictograms
Pictograms that appear on the machine are
explained in this Instruction Manual.
Depending on the machine and equipment ver‐
sion, the following pictograms may appear on the
machine.
Fuel tank; fuel mixture of gasoline
and engine oil
Tank for chain oil; chain oil
Engage and release chain brake
Coasting brake
Direction of chain travel
Ematic; chain oil flow adjustment
Tension saw chain
Intake air baffle: winter operation
Intake air baffle: summer operation
Handle heating
Actuate decompression valve
Actuate manual fuel pump
English
2 0458-508-8321-B
© ANDREAS STIHL AG & Co. KG 2021
0458-508-8321-B. VA0.D21.
Printed on chlorine-free paper Printing inks contain vegetable oils, paper can be recycled.
Original Instruction Manual 0000008662_003_GB

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
This special chain saw shall be used
only by persons who are trained in
special cutting and working techni‐
ques.
Due to the special handle design
(closely spaced handles) there is an
increased risk of injury using this kind
of saw (cut injuries due to uncontrol‐
led reactive forces of the chain saw).
Special safety precautions must be
observed to reduce the risk of per‐
sonal injury when working with a
chainsaw because of the very high
chain speed and very sharp cutters.
It is important that you read the
instruction manual before first use
and keep it in a safe place for future
reference. Non-observance of the
instruction manual may result in seri‐
ous or even fatal injury.
2.1 General
Observe all applicable local safety regulations,
standards and ordinances.
The use of noise emitting power tools may be
restricted to certain times by national or local
regulations.
If you have not used this model before: Have
your dealer or other experienced user show you
how to operate your machine or attend a special
course in its operation.
Minors should never be allowed to use a chain‐
saw. Exceptions to this rule are young persons
older than 16 who have been trained in special
cutting techniques with the tree surgery saw.
Keep bystanders, especially children, and ani‐
mals away from the work area.
The user is responsible for avoiding injury to third
parties or damage to their property.
Do not lend or rent your chain saw without the
instruction manual. All users must be specially
trained in tree surgery work with a tree surgery
saw and be familiar with this model and its oper‐
ation.
To operate a chain saw you must be rested, in
good physical condition and mental health. If you
have any condition that might be aggravated by
strenuous work, check with your doctor before
operating a chainsaw.
Do not operate the chain saw if you are under
the influence of any substance (drugs, alcohol)
which might impair vision, dexterity or judgment.
To reduce the risk of accidents or injury, put off
the work in poor weather conditions (rain, snow,
ice, wind).
Persons with pacemakers only: The ignition sys‐
tem of your chainsaw produces an electromag‐
netic field of a very low intensity. This field may
interfere with some pacemakers. To reduce
health risks, STIHL recommends that persons
with pacemakers consult their physician and the
pacemaker manufacturer before operating this
power tool.
2.2 Intended Use
Tree surgery chainsaws are special-purpose
saws equipped with a top handle. They are
designed specifically for tree surgery and mainte‐
nance in the crown of the standing tree.
Chainsaw operators must be properly secured
while working in a tree (e.g. lift bucket, personal
safety equipment, safety harness).
The chainsaw may be used for cutting wood and
wooden objects only.
It must not be used for any other purpose
because of the increased risk of accidents.
They must not be used for felling trees or cutting
firewood. Normal chainsaws with wider spaced
handles are recommended for such operations.
Never attempt to modify your saw in any way
since this may increase the risk of personal
injury. STIHL excludes all liability for personal
2 Safety Precautions English
0458-508-8321-B 3

injury and damage to property caused while
using unauthorized attachments.
This chainsaw is designed for tree maintenance
work, e.g. pruning small branches. For this rea‐
son it comes standard without a spiked bumper.
A spiked bumper (available as special acces‐
sory) may be mounted if required.
2.3 Clothing and Equipment
Wear proper protective clothing and equipment.
Clothing must be sturdy and snug-fit‐
ting, but allow complete freedom of
movement. Wear snug-fitting clothing
with cut-retardant pads for feet, legs,
hands and forearms – an overall, not
a loose-fitting jacket.
Avoid clothing that could get caught on
branches, brush or moving parts of the machine.
Do not wear a scarf, necktie or jewelery. Tie up
and confine long hair (headscarf, cap, hard hat,
etc.).
Wear suitable safety shoes – with cut-
retardant material, non-slip soles and
steel toe caps.
WARNING
To reduce the risk of eye injuries,
wear tight-fitting safety goggles con‐
forming to standard EN 166. Make
sure that the safety goggles fit cor‐
rectly.
Wear a face shield and make sure it fits cor‐
rectly.
Wear "personal" hearing protection – for exam‐
ple, ear defenders.
Wear a hard hat with a chin strap wherever there
is any risk of falling objects.
Wear sturdy protective gloves made
of a resistant material (e.g. leather) –
with cut-retardant material.
STIHL can supply a comprehensive range of per‐
sonal protective clothing and equipment.
Use a personal fall arrest system.
Use only certified equipment that is suitable for
the application concerned.
Check the condition of the equipment before use
and replace broken parts.
2.4 Transporting
Always stop the engine, engage the chain brake
and fit the chain guard (scabbard) before carry‐
ing the saw short distances. This avoids the risk
of the chain running unintentionally.
0012BA024 KN
Always carry the saw by the control handle – with
the hot muffler away from your body – the guide
bar must point to the rear. To reduce the risk of
serious burn injuries, avoid touching hot parts of
the machine, especially the surface of the muf‐
fler.
In vehicles: Properly secure your saw to prevent
turnover, fuel spillage and damage.
2.5 Cleaning
Clean plastic parts with a cloth. Harsh detergents
can damage the plastic.
Clean the dust and dirt off the machine – do not
use any grease solvents for this purpose.
Clean the ventilation slots if necessary.
Do not use a high-pressure cleaner to clean the
machine. The hard jet of water can damage parts
of the machine.
2.6 Accessories
Only use those tools, guide bars, chains, chain
sprockets, accessories or technically equivalent
components that have been approved by STIHL
for this machine. 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 and damage to
the machine.
STIHL recommends the use of genuine STIHL
tools, guide bars, chains, chain sprockets and
accessories. They are specifically designed to
match your model and meet your performance
requirements.
English 2 Safety Precautions
4 0458-508-8321-B

2.7 Refuelling
Gasoline is an extremely flammable
fuel – keep clear of naked flames and
fire – do not spill any fuel – no smok‐
ing.
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 ven‐
tilated place. Clean the machine immediately if
fuel is spilled. Do not spill fuel over your clothing
– contaminated clothing must be changed imme‐
diately.
The machines can be equipped with the follow‐
ing filler caps as standard:
Cliplock filler cap (bayonet-type)
Place the cliplock filler cap (bayonet-
type) in position, turn as far as stop
and fold the cliplock down.
This helps reduce the risk of unit vibrations caus‐
ing an incorrectly tightened filler cap to loosen or
come off and spill quantities of fuel.
Look out for leaks! Never start the
engine if fuel has been spilled or is
leaking – Fatal burns may result!
2.8 Before Starting Work
Check that your saw is properly assembled and
in good condition – refer to appropriate chapters
in the instruction manual.
–Check the fuel system for leaks, paying spe‐
cial attention to visible parts such as the tank
cap, hose connections and the manual fuel
pump (on machines so equipped). If there are
any leaks or damage, do not start the engine –
risk of fire. Have your saw repaired by a serv‐
icing dealer before using it again.
–Check operation of chain brake, front hand
guard
–Correctly mounted guide bar
–Correctly tensioned chain
–The trigger and trigger lockout must move
freely and spring back to the idle position
when they are released.
–Master Control lever must move easily to
STOP, 0 or †
–Check that the spark plug boot is secure – a
loose boot may cause arcing that could ignite
combustible fumes and cause a fire.
–Never attempt to modify the controls or safety
devices in any way.
–Keep the handles dry and clean – free from oil
and dirt – for safe control of the saw.
–Make sure there is sufficient fuel and chain oil
in the tanks.
To reduce the risk of personal injury, do not
operate your saw if it is damaged or not properly
assembled.
2.9 Starting the Saw
Start the saw on level ground only. Make sure
you have a firm footing. Hold the saw firmly. To
reduce the risk of injury from the rotating chain,
check that the cutting attachment is not touching
any object or the ground .
The chainsaw is a one-person saw. Do not allow
other persons in the work area – even when
starting.
Do not attempt to start the saw when the saw
chain is in a cut.
Starting the saw in a tree is very dangerous
since the user may lose control of the machine –
risk of injury.
The tree surgery saw should be checked, fueled,
started and warmed up by an assistant on the
ground before it is transported up to the operator
in the tree.
Start the engine at least 3 meters from the fuel‐
ing spot, outdoors only.
To reduce risk of chain rotation and personal
injury, lock the chain with the chain brake before
starting.
Do not drop start the power tool – start the
engine as described in the instruction manual.
2.10 During Operation
When working in the tree, always secure the
chainsaw with a rope – tie it to the ring and
attach it to the lifeline. Always engage the chain
brake before letting the chainsaw hang by the
rope.
2 Safety Precautions English
0458-508-8321-B 5

0012BA019 KN
H
L
To reduce the risk of accidents and
injuries, always hold your saw firmly
with both hands: Right hand on the
control handle, even if you are left-
handed. To ensure safe control, wrap
your fingers tightly around both han‐
dles.
One-handed operation is particularly
dangerous, e.g. when cutting dry,
knotty and dead wood, the chain may
not enter the cut properly. The resul‐
tant reactive forces may cause the
saw to skate or bounce on the limb
and slide out of control. This increa‐
ses the risk of serious or even fatal
injury.
Use the tree surgery chainsaw with one hand
only:
–if two-handed cutting is not possible and
–if one hand is required for support during the
cut and
–if the saw is held firmly and
–if all parts of your body are clear of the cutting
attachment.
During one-handed cutting:
–never support yourself on the limb being cut
–never cut with the bar nose
–never attempt to hold falling limbs
Make sure you always have good balance and
secure footing. To avoid slipping, take special
care when the bark is wet.
In the event of impending danger or in an emer‐
gency, switch off the engine immediately – move
the Master Control lever in the direction of
STOP, 0 or †.
Never leave a running saw unattended.
Take special care in slippery conditions – damp,
snow, ice, on slopes, uneven ground and freshly
debarked logs.
Watch out for obstacles such as tree stumps,
roots and ditches which could cause you to trip
or stumble.
Do not work alone – keep within calling distance
of other persons trained in first aid who can pro‐
vide assistance in an emergency. Helpers at the
cutting site must also wear protective clothing
(hard hat) and stand well clear of the branches
being cut.
Be particularly alert and cautious when wearing
hearing protection because your ability to hear
warnings (shouts, alarms, etc.) is restricted.
To reduce the risk of accidents, take a break in
good time to avoid tiredness or exhaustion.
The dusts (e.g. sawdust), vapor and smoke pro‐
duced during operation may be dangerous to
health. If dust levels are very high, wear a suita‐
ble respirator.
When the engine is running: Note that the chain
continues to rotate for a short period after you let
go of the throttle trigger (flywheel effect).
To reduce the risk of fire, do not smoke while
operating or standing near your chainsaw. Note
that combustible fuel vapor may escape from the
fuel system.
Check the saw chain at regular short intervals
during operation or immediately if there is a
noticeable change in cutting behavior:
–Shut off the engine and wait until the chain
comes to a complete standstill.
–Check condition and proper mounting.
–Check sharpness.
Do not touch the chain while the engine is run‐
ning. If the chain becomes jammed by an
obstruction, switch off the engine immediately
before attempting to remove the obstruction –
risk of injury.
Always shut off the engine before leaving the
saw unattended.
Shut off the engine before changing the saw
chain. This avoids the risk of injury from the
engine starting unintentionally.
To reduce risk of fire, keep hot exhaust gases
and hot muffler away from easily combustible
materials (e.g. wood chips, bark, dry grass, fuel).
Mufflers with a catalytic converter can become
particularly hot.
Never operate your saw without proper chain
lubrication – check oil level regularly during oper‐
ation. Stop work immediately if the oil level is too
low and refill the oil tank – see also chapters on
"Filling Chain Oil Tank" and "Checking Chain
Lubrication".
English 2 Safety Precautions
6 0458-508-8321-B

If your saw 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 Start‐
ing Work".
Check the fuel system in particular for leaks and
make sure the safety devices are working prop‐
erly. Do not continue operating your saw if it is
damaged. In case of doubt, have the unit
checked by your servicing dealer.
Make sure the idle speed setting is correct. The
chain must not run when the engine is idling with
the throttle trigger released. Check and correct
the idle speed setting regularly. It the chain con‐
tinues to rotate when the engine is idling, have
your dealer make proper adjustments or repairs.
The chain saw produces poisonous
exhaust gases as soon as the engine
starts. These gases may be colour‐
less and odourless and may contain
unburnt hydrocarbons and benzene.
Never work with the machine indoors
or in poorly ventilated areas, even if
your machine is equipped with a cata‐
lytic converter.
Ensure proper ventilation when working in
trenches, hollows or other confined locations –
risk of fatal injury from breathing toxic fumes!
If you feel sick, have a headache, vision prob‐
lems (e. g., your field of vision gets smaller),
hearing problems, dizziness or inability to con‐
centrate, stop work immediately. Such symptoms
may be caused by an excessively high concen‐
tration of exhaust emissions – risk of accident!
2.11 After finishing work
Switch off the motor, engage the chain brake and
attach the chain scabbard.
2.12 Storage
When the machine is not in use, it should be
stored in such a way that no-one is endangered.
Secure the machine against unauthorised use.
Store the machine in a safe, dry room.
2.13 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).
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.
2.14 Maintenance and repairs
Always switch off the engine before any repair,
cleaning or maintenance work and any work on
the chain. Risk of injury if the engine starts inad‐
vertently!
Exception: adjustment of carburettor and idle
speed.
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 authorised 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 and damage to
the machine. If you have any questions in this
respect, consult a servicing dealer.
Do not modify the machine in any way – this may
increase the risk of personal injury –risk of acci‐
dents!
To reduce the risk of fire due to ignition outside
the cylinder, move the master control level to
STOP, 0 or † before turning the engine over on
the starter when the spark plug boot is removed
or the spark plug is 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 "Speci‐
fications".
Check ignition lead (insulation in good condition,
secure connection).
2 Safety Precautions English
0458-508-8321-B 7

Check that the muffler is in perfect working con‐
dition.
Do not use the machine if the muffler is damaged
or missing – risk of fire, damage to hearing!
Never touch a hot muffler – risk of burns!
The condition of the anti-vibration elements influ‐
ences vibration behaviour – inspect anti-vibration
elements periodically.
Inspect chain catcher – replace if damaged.
Switch off the engine
–To check the chain tension
–To retension the chain
–To replace the chain
–For remedying malfunctions
Observe sharpening instructions – for safe and
proper handling, always keep the chain and
guide bar in flawless condition. Keep the chain
properly sharpened, tensioned and well lubrica‐
ted.
Change chain, guide bar and chain sprocket in
due time.
Regularly check that the clutch drum is in perfect
working condition.
Always store fuel and chain lubricant only in the
specified type of containers and ensure they are
correctly labelled. Store in a dry, cool and secure
place protected against light and sunlight.
In the event of a chain brake malfunction, switch
off the machine immediately – risk of injury! Con‐
sult a servicing dealer – do not use the machine
until the malfunction has been remedied, see
"Chain brake".
3 Reactive Forces
The most common reactive forces that occur dur‐
ing cutting are: kickback, pushback and pull-in.
3.1 Dangers of kickback
Kickback can result in serious or fatal
injury.
0012BA022 KN
(Kickback) occurs when the saw is suddenly
thrown up and back in an uncontrolled arc
towards the operator.
3.2 Kickback occurs if, e. g.,
001BA257 KN
–when the upper quadrant of the bar nose unin‐
tentionally contacts wood or another solid
object, e.g. when another limb is touched acci‐
dentally during limbing.
–when the chain at the nose of the guide bar is
pinched in the cut.
3.3 Quickstop chain brake:
This device reduces the risk of injury in certain
situations – it cannot prevent kickback. When
activated, the chain brake stops the saw chain
within a fraction of a second –
see the section "Saw chain" in this Instruction
Manual.
3.4 To reduce the risk of kickback
–Work cautiously and avoid situations which
could cause kickback.
–Hold the saw firmly with both hands and main‐
tain a secure grip.
–always cut at full throttle.
–Be aware of the location of the guide bar nose
at all times.
–do not cut with the bar nose.
–Take special care with small, tough limbs, they
may catch the chain.
–never cut several limbs at once.
–do not overreach.
English 3 Reactive Forces
8 0458-508-8321-B

–never cut above shoulder height.
–Use extreme caution when re-entering a previ‐
ous cut.
–Do not attempt plunge cuts if you are not
experience in this cutting technique.
–be alert for shifting of the log or other forces
that may cause the cut to close and pinch the
chain.
–always cut with a correctly sharpened, prop‐
erly tensioned chain – the depth gauge setting
must not be too large.
–Use a low kickback chain and a narrow radius
guide bar.
3.5 Pull-in (A)
001BA037 KN
A
Pull-in occurs when the chain on the bottom of
the bar is suddenly pinched, caught or encoun‐
ters a foreign object in the wood. The reaction of
the chain pulls the saw forward – to reduce this
risk, always engage the spiked bumper securely
in the tree or limb.
3.6 Pushback (B)
001BA038 KN
B
Pushback occurs when the chain on the top of
the bar is suddenly pinched, caught or encoun‐
ters a foreign object in the wood. The reaction of
the chain drives the saw straight back toward the
operator – to avoid this risk:
–Be alert to situations that may cause the top of
the guide bar to be pinched
–Do not twist the guide bar in the cut
4 Working Techniques
4.1 Sawing
Do not operate your saw in the starting throttle
position. Engine speed cannot be controlled with
the throttle trigger in this position.
Work calmly and carefully – in daylight conditions
and only when visibility is good. Ensure you do
not endanger others – stay alert at all times.
Use the shortest possible guide bar: The chain,
guide bar and chain sprocket must match each
other and your saw.
9923BA034 KN
Position the saw so that your body is clear of the
cutting attachment.
%$/
If conditions allow, work from a lift bucket.
Never work on a ladder or on any other insecure
support, do not work above shoulder height.
Cordon off the work area in order to reduce the
risk of injuries and damage to bystanders or
property (e. g. motor vehicles) from falling
branches.
When working with a lifeline there is a risk of cut‐
ting through the rope – to reduce the risk of fall
injuries,always use double lifelines.
Take special care when cutting through a limb.
Hold the machine firmly to control and counteract
the feed force. At the end of the cut, the chain
saw is no longer supported by the cutting attach‐
ment in the cut. You have to take the full weight
4 Working Techniques English
0458-508-8321-B 9

of the chainsaw since it might otherwise go out of
control!
Make sure your saw does not touch any foreign
materials: Stones, nails, etc. may be flung off
and damage the saw chain. The chain saw may
kick back unexpectedly – risk of accident!
If a rotating saw chain hits a stone or another
hard object, sparks may be generated which may
ignite easily flammable materials under certain
conditions. Also dried-out plants and brushwood
are combustible, above all in hot and dry
weather. If there is a risk of fire, do not use the
chain saw in the vicinity of easily combustible
materials, dry plants or scrub. It is mandatory
that you ask the responsible forestry office about
the current fire hazard.
Caution! To avoid risk of electrocu‐
tion, take extra precautions when cut‐
ting near power lines. Have the power
switched off before starting cutting
work in the immediate vicinity of
power lines.
Do not underbuck freely hanging limbs because
the chain may get pinched and cause kickback
and loss of control.
Be careful when cutting scrub and young trees.
Thin shoots can be scooped up by the chain saw
and hurled towards the user.
Be careful when cutting splintered wood – Risk of
injury from ejected pieces of wood!
After finishing a cut, activate the chain brake to
lock the chain or shut down the engine before
moving the saw to another position in the tree.
Cutting techniques:
Begin cutting with the chain saw at full throttle.
Always pull the saw out of the cut with the chain
running.
–Cut straight through thin limbs
–In case of thick limbs, first perform relieving
cut from below (approx. 1/5 of diameter), then
buck from above
–Support and secure heavy branches with
ropes.
If the saw gets pinched in the cut:
–Shut off the engine and secure the saw to the
tree – in direction of trunk.
–Carefully free the saw from the cut, using
another saw if necessary.
Limbs under tension:
► Always start relieving cut (1) at compression
side (A)
► Then make bucking cut (2) at the tension
side (B) into the direction of the log – other‐
wise the chain saw may pinch or kick back
If not otherwise possible, make the bucking cut
from the bottom upwards (underbuck) – be wary
of pushback.
5 Cutting Attachment
A cutting attachment consists of the saw chain,
guide bar and chain sprocket.
The cutting attachment that comes standard is
designed to exactly match the chain saw.
001BA248 KN
1
2
3
a
–The pitch (t) of the saw chain (1), chain
sprocket and the nose sprocket of the Rollo‐
matic guide bar must match.
–The drive link gauge (2) of the saw chain (1)
must match the groove width of the guide
bar (3).
If non-matching components are used, the cut‐
ting attachment may be damaged beyond repair
after a short period of operation.
English 5 Cutting Attachment
10 0458-508-8321-B

5.1 Chain Scabbard
001BA244 KN
Your saw comes standard with a chain scabbard
that matches the cutting attachment.
If guide bars of different lengths are mounted to
the saw, always use a chain scabbard of the cor‐
rect length which covers the complete guide bar.
The length of the matching guide bars is marked
on the side of the chain scabbard.
6 Mounting the Bar and
Chain
6.1 Disengage the chain brake
3006BA001 KN
► Pull the hand guard towards the front handle
until there is an audible click – the chain brake
is disengaged.
6.2 Removing the chain sprocket
cover
1
2011BA050 KN
2
► Unscrew the nut (1) and remove the chain
sprocket cover (2)
6.3 Mounting the Guide Bar
2011BA051 KN
1
2
► Turn the screw (1) to the left until the tensioner
slide (2) butts against the left end of the hous‐
ing slot
4
3
2011BA052 KN
► Fit the guide bar over the stud (3) and engage
the peg of the tensioner slide in the hole (4)
6.4 Fitting the saw chain
WARNING
Wear work gloves to protect your hands from the
sharp cutters!
2011BA053 KN
1
► Fit chain around the sprocket (1) and over the
guide bar – the cutting edges on top of the bar
must point to the bar nose
6 Mounting the Bar and Chain English
0458-508-8321-B 11

2
2011BA054 KN
► Turn the screw (2) clockwise until there is very
little chain sag on the underside of the bar –
and the drive link tangs are engaged in the bar
groove
3006BA002 KN
► Refit the sprocket cover –
the pivot pin on the hand guard must engage
the guard on the engine housing – and then
screw the nut onto the stud fingertight
► go to chapter "Tensioning the Chain"
7 Tensioning the Saw Chain
(side chain tensioner)
1
2011BA056 KN
Retensioning during cutting work:
► Shut off the engine.
► Loosen the nut.
► Hold the bar nose up.
► Use a screwdriver to turn the tensioning
screw (1) clockwise until the chain fits snugly
against the underside of the bar.
► While still holding the bar nose up, tighten
down the nut firmly.
► Go to "Checking Chain Tension".
A new chain has to be retensioned more often
than one that has been in use for some time.
► Check chain tension frequently – see chapter
on "Operating Instructions".
8 Checking Chain Tension
2011BA057 KN
► Shut off the engine.
► Wear work gloves to protect your hands.
► The chain must fit snugly against the under‐
side of the bar and it must still be possible to
pull the chain along the bar by hand when the
chain brake is released.
► If necessary, retension the chain.
A new chain has to be retensioned more often
than one that has been in use for some time.
► Check chain tension frequently – see chapter
on "Operating Instructions".
9 Fuel
Your engine requires a mixture of gasoline and
engine oil.
WARNING
For health reasons, avoid direct skin contact with
gasoline and avoid inhaling gasoline vapor.
9.1 STIHL MotoMix
STIHL recommends the use of STIHL MotoMix.
This ready-to-use fuel mix contains no benzol or
lead, has a high octane rating and ensures that
you always use the right mix ratio.
STIHL MotoMix uses STIHL HP Ultra two-stroke
engine oil for an extra long engine life.
MotoMix is not available in all markets.
English 7 Tensioning the Saw Chain (side chain tensioner)
12 0458-508-8321-B

9.2 Mixing Fuel
NOTICE
Unsuitable fuels or lubricants or mix ratios other
than those specified may result in serious dam‐
age to the engine. Poor quality gasoline or
engine oil may damage the engine, sealing rings,
hoses and the fuel tank.
9.2.1 Gasoline
Use only high-quality brand-name gasoline with
a minimum octane rating of 90 – leaded or unlea‐
ded.
Gasoline with an ethanol content of more than
10% can cause running problems in engines with
a manually adjustable carburetor and should not
be used in such engines.
Engines equipped with M-Tronic deliver full
power when run on gasoline with an ethanol con‐
tent of up to 25% (E25).
9.2.2 Engine Oil
If you mix the fuel yourself, use only STIHL two-
stroke engine oil or another high-performance
engine oil in accordance with JASO FB, JASO
FC, JASO FD, ISO-L-EGB, ISO-L-EGC or ISO-L-
EGD.
STIHL specifies STIHL HP Ultra two-stroke
engine oil or an equivalent high-performance
engine oil in order to maintain emission limits
over the machine’s service life.
9.2.3 Mix Ratio
STIHL 50:1 two-stroke engine oil: 50 parts gaso‐
line to 1 part oil
9.2.4 Examples
Gasoline STIHL engine oil 50:1
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)
► Use a canister approved for storing fuel. Pour
oil into canister first, then add gasoline and
mix thoroughly.
9.3 Storing Fuel
Store fuel only in approved safety-type fuel can‐
isters in a dry, cool and safe location protected
from light and the sun.
Fuel mix ages – only mix sufficient fuel for a few
weeks work. Do not store fuel mix for longer than
30 days. Exposure to light, the sun, low or high
temperatures can quickly make the fuel mix
unusable.
STIHL MotoMix may be stored for up to 2 years
without any problems.
► Thoroughly shake the mixture in the canister
before fueling your machine.
WARNING
Pressure may build up in the canister – open it
carefully.
► Clean the fuel tank and canister from time to
time.
Dispose of remaining fuel and cleaning fluid
properly in accordance with local regulations and
environmental requirements.
10 Fueling
10.1 Preparations
2011BA010 KN
► Before fueling, clean the filler cap and the area
around it to ensure that no dirt falls into the
fuel tank.
► Position the machine so that the filler cap
faces up.
10 Fueling English
0458-508-8321-B 13

10.2 Opening
001BA236 KN
► Raise grip to vertical position.
001BA232 KN
► Turn the cap counterclockwise (about a quar‐
ter turn).
001BA234 KN
Marks on tank cap and fuel tank must line up.
001BA237 KN
► Remove the tank cap.
10.3 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 noz‐
zle for fuel (special accessory).
► Fill the fuel tank.
10.4 Closing
001BA234 KN
Grip must be vertical:
► Fit the cap – marks on tank cap and fuel tank
must line up.
► Press the cap down as far as stop.
001BA233 KN
► While holding the cap depressed, turn it clock‐
wise until it engages in position.
001BA231 KN
The marks on the tank cap and fuel tank are then
in alignment.
English 10 Fueling
14 0458-508-8321-B

001BA235 KN
► Fold the grip down.
001BA241 KN
Tank cap is locked.
10.5 If the tank cap cannot be
locked in the fuel tank opening
Bottom of cap is twisted in relation to top.
► Remove the cap from the fuel tank and check
it from above.
1
001BA238 KN
Left: Bottom of cap is twisted – inner
mark (1) in line with outer mark.
Right: Bottom of cap in correct position –
inner mark is under the grip. It is not
in line with the outer mark.
001BA239 KN
► Place the cap on the opening and rotate it
counterclockwise until it engages the filler
neck.
► Continue rotating the cap counterclockwise
(about a quarter turn) – this causes the bottom
of the cap to be turned to the correct position.
► Turn the cap clockwise and lock it in position –
see section on "Closing".
11 Chain Lubricant
For automatic and reliable lubrication of the
chain and guide bar – use only an environmen‐
tally compatible quality chain and bar lubricant.
Rapidly biodegradable STIHL BioPlus is recom‐
mended.
NOTICE
Biological chain oil must be resistant to aging
(e.g. STIHL BioPlus), since it will otherwise
quickly turn to resin. This results in hard deposits
that are difficult to remove, especially in the area
of the chain drive and chain. It may even cause
the oil pump to seize.
The service life of the chain and guide bar
depends on the quality of the lubricant. It is
therefore essential to use only a specially formu‐
lated chain lubricant.
11 Chain Lubricant English
0458-508-8321-B 15

WARNING
Do not use waste oil. Renewed contact with
waste oil can cause skin cancer. Moreover,
waste oil is environmentally harmful.
NOTICE
Waste oil does not have the necessary lubricat‐
ing properties and is unsuitable for chain lubrica‐
tion.
12 Filling Chain Oil Tank
12.1 Preparations
2011BA011 KN
► Thoroughly clean the oil filler cap and the area
around it to ensure that no dirt falls into the
tank.
► Position the machine so that the filler cap
faces up.
► Open the filler cap.
12.2 Filling up with chain oil
► Refill the chain oil tank every time you refuel.
Take care not to spill chain oil while refilling and
do not overfill the tank.
STIHL recommends you use the STIHL filler noz‐
zle for chain oil (special accessory).
► Closing the Tank Cap
There must still be a small amount of oil in the oil
tank when the fuel tank is empty.
If the oil level in the tank does not go down, the
reason may be a fault in the oil supply system:
Check chain lubrication, clean the oilways, con‐
tact your dealer for assistance if necessary
STIHL recommends that you have servicing and
repair work carried out exclusively by an author‐
ized STIHL servicing dealer.
13 Checking Chain Lubrica‐
tion
%$.1
The saw chain must always spin off a small
amount of oil.
NOTICE
Never operate your machine without chain lubri‐
cation. If the saw chain runs dry, the cutting
attachment may very quickly be damaged
beyond repair. Before starting work, always
check the chain lubrication and oil level in the
tank.
Every new saw chain needs a run-in time of 2 to
3 minutes.
After the saw chain has run in, check the tension
of the chain and correct if necessary – see
"Checking the chain tension".
14 Chain Brake
14.1 Locking the Chain
3006BA003 KN
–in an emergency
–when starting
–at idling speed
The chain brake is activated by pushing the hand
guard toward the bar nose with your left hand –
English 12 Filling Chain Oil Tank
16 0458-508-8321-B

or by inertia in certain kickback situations: The
chain is stopped and locked.
14.2 Disengaging the Chain Brake
3006BA001 KN
► Pull the hand guard towards the front handle
until there is an audible click – the chain brake
is disengaged.
NOTICE
Always disengage chain brake before accelerat‐
ing the engine (except when checking its opera‐
tion) and before starting cutting work.
High revs with the chain brake engaged (chain
locked) will quickly damage the powerhead and
chain drive (clutch, chain brake).
The chain brake is also activated by the inertia of
the front hand guard if the kickback force of the
saw is high enough: The hand guard is acceler‐
ated toward the bar nose.
The chain brake will operate only if the hand
guard has not been modified in any way.
14.3 Checking Operation of the
Chain Brake
Before starting work: Run engine at idle speed,
engage the chain brake (push hand guard
towards bar nose) and open the throttle wide for
no more than 3 seconds – the chain must not
rotate. The hand guard must be free from dirt
and move freely.
14.4 Chain Brake Maintenance
The chain brake is subject to normal wear. It is
necessary to have it serviced and maintained
regularly by trained personnel. STIHL recom‐
mends that you have servicing and repair work
carried out exclusively by an authorized STIHL
servicing dealer. Maintain the following servicing
intervals:
Full-time usage: every 3 months
Part-time usage: every 6 months
15 Starting / Stopping the
Engine
15.1 Positions of the Master Control
lever
2011BA042 KN
Stop 0 – engine off – the ignition is switched off
Normal run position (F) – engine runs or can fire.
Starting throttle n – for starting the engine
15.2 Positions of Choke Shutter
2011BA043 KN
Choke shutter closed l – for starting the engine
–if the engine is cold
–if the engine stalls during opening of throttle
after starting
–If the fuel tank was run until empty (engine
stopped).
Choke shutter open j – for starting the engine
–if engine is warm (once the engine has been
running for approx. one minute)
–When Engine Begins to Fire
–after ventilation of the combustion chamber, if
the engine was flooded
15.3 Adjust Master Control lever
To move the Master Control lever from the nor‐
mal run position (F) to starting throttle (n), press
down the throttle trigger lockout and squeeze the
15 Starting / Stopping the Engine English
0458-508-8321-B 17

throttle trigger at the same time and hold them in
that position – now set the Master Control lever.
The Master Control lever moves from the starting
throttle position (n) to the run position (F) when
you press down the throttle trigger lockout and
blip the throttle trigger at the same time.
To switch off the engine, set the master control
lever to Stop 0.
15.4 Manual fuel pump
The manual fuel pump bulb must be pressed:
–When starting for the first time
–If the fuel tank was run until empty (engine
stopped).
15.5 Holding the Chain Saw
3009BA005 KN
► Place your saw on the ground. Make sure you
have a firm footing – check that the chain is
not touching any object or the ground.
► Hold the control handle of the chain saw firmly
in the right hand
► Support the right knee on the carburetor cover
15.6 Actuating
► Pull the starter grip slowly with your right hand
until you feel it engage – and then give it a
brisk strong pull and push down the control
handle at the same time. Do not pull out the
starter rope to full length – it might otherwise
break. Do not let the starter grip snap back.
Guide it slowly back into the housing so that
the starter rope can rewind properly.
15.7 Starting the Chainsaw
WARNING
Bystanders must be well clear of the general
work area of the saw.
2011BA014 KN
► Press the manual fuel pump bulb at least 9
times - even when bulb is filled with fuel
3006BA007 KN
4
1
2
3
► Push the hand guard (1) forward – the chain is
locked.
► Press down the trigger lockout (2) and pull the
throttle trigger (3) at the same time. Set Mas‐
ter Control lever (4) to starting throttle posi‐
tion (n).
► Set choke lever to required position.
Position choke shutter closed l
3006BA021 KN
–if engine is cold (even if the engine has stalled
during opening of throttle after starting)
English 15 Starting / Stopping the Engine
18 0458-508-8321-B

Choke shutter open (j)
3006BA022 KN
–if engine is warm (once the engine has been
running for approx. one minute)
► Hold and start your saw as described.
15.8 When Engine Begins to Fire
3006BA022 KN
► Move the choke lever to the open posi‐
tion (j ).
► Hold and start your saw as described.
15.9 As Soon As the Engine Runs
3006BA008 KN
4
3
► Press down the trigger lockout and blip the
throttle trigger (3) – the Master Control
lever (4) moves to the run position (F) and the
engine settles down to idling speed.
3006BA001 KN
► Pull the hand guard toward the control handle
to disengage the chain brake.
NOTICE
Open the throttle only when the chain brake is
off. Increased engine speeds with the chain
brake on (saw chain is stationary) will quickly
damage the clutch and chain brake.
► After a cold start, warm up the engine at vary‐
ing speeds – your saw is ready for operation.
15.10 At Very Low Outside Tempera‐
tures
In case of erratic idling behaviour or poor accel‐
eration
► Readjust carburetor if necessary, see "Adjust‐
ing the Carburetor".
► If your saw is very cold (frost or ice on
machine), start the engine and keep it at a
high idle speed (with chain brake disengaged)
until it reaches normal operating temperature.
15.11 Shut off the engine
► Move Master Control lever to Stop 0.
15.12 If Engine Does Not Start
If you did not move the Master Control lever from
the choke closed position (l) to the choke open
position (j) quickly enough after the engine
began to fire, the engine is probably flooded.
► Move Master Control lever to Stop 0.
15 Starting / Stopping the Engine English
0458-508-8321-B 19

► Remove the spark plug – see "Spark Plug".
► Dry the spark plug
► Crank the engine several times with the starter
to clear the combustion chamber.
► Refit the spark plug – see "Spark Plug".
► Set the master control lever to starting accel‐
eration n – even if the engine is cold
► Restart the engine
15.13 If Fuel Tank Has Been Run
Completely Dry and Then
Refueled
► Press the bellows of the manual fuel pump at
least 9x
► Set the Master Control lever to the starting
throttle position (n).
► Move the choke lever to the closed posi‐
tion (l)
► Continue cranking 2x
► Move the choke lever to the open posi‐
tion (j ).
► Restart the engine
16 Operating Instructions
16.1 During the break-in period
A factory new machine should not be run at high
revs (full throttle off load) for the first three tank
fillings. This avoids unnecessarily high loads dur‐
ing the break-in period. As all moving parts have
to bed in during the break-in period, the frictional
resistances in the shortblock are greater during
this period. The engine develops its maximum
power after about 5 to 15 tank fillings.
16.2 During work
NOTICE
Do not make the mixture leaner to achieve an
apparent increase in power – this could damage
the engine – see "Adjusting the Carburetor".
NOTICE
Open the throttle only when the chain brake is
off. Running the engine at high revs with the
chain brake engaged (chain locked) will quickly
damage the shortblock and chain drive (clutch,
chain brake).
16.2.1 Check chain tension frequently
A new saw chain must be retensioned more fre‐
quently than one that has been in use already for
an extended period.
16.2.2 Chain cold
Tension is correct when the chain fits snugly
against the underside of the bar but can still be
pulled along the bar by hand. Retension if neces‐
sary – see "Tensioning the Saw Chain".
16.2.3 Chain at operating temperature
The chain stretches and begins to sag. The drive
links must not come out of the bar groove on the
underside of the bar – the chain may otherwise
jump off the bar. Retension the chain – see "Ten‐
sioning the Saw Chain".
NOTICE
The chain contracts as it cools down. If it is not
slackened off, it can damage the crankshaft and
bearings.
16.2.4 After a long period of full-throttle oper‐
ation
After a long period of full-throttle operation, allow
engine to run for a while at idle speed so that the
heat in the engine can be dissipated by flow of
cooling air. This protects engine-mounted com‐
ponents (ignition, carburetor) from thermal over‐
load.
16.3 After finishing work
► Slacken off the chain if you have retensioned it
at operating temperature during work.
NOTICE
Always slacken off the chain again after finishing
work. The chain contracts as it cools down. If it is
not slackened off, it can damage the crankshaft
and bearings.
16.3.1 Short-term storage
Wait for engine to cool down. Keep the machine
with a full tank of fuel in a dry place, well away
from sources of ignition, until you need it again.
16.3.2 Long-term storage
See "Storing the machine"
English 16 Operating Instructions
20 0458-508-8321-B