Stihl MS 151 C User manual

MS 151 C
Instruction Manual2 - 39

Contents
1 Guide to Using this Manual.........................2
2 Safety Precautions......................................3
3 Reactive Forces.......................................... 7
4 Working Techniques................................... 9
5 Cutting Attachment................................... 15
6 Mounting the Bar and Chain..................... 16
7 Tensioning the Saw Chain (side chain ten‐
sioner)....................................................... 17
8 Checking Chain Tension...........................17
9 Fuel........................................................... 17
10 Fueling...................................................... 18
11 Chain Lubricant.........................................20
12 Filling Chain Oil Tank................................21
13 Checking Chain Lubrication...................... 21
14 Chain Brake.............................................. 21
15 Starting / Stopping the Engine.................. 22
16 Operating Instructions...............................25
17 Taking Care of the Guide Bar................... 26
18 Cleaning the Air Filter............................... 26
19 Adjusting the Carburetor........................... 26
20 Spark Plug................................................ 27
21 Storing the Machine.................................. 28
22 Checking the Chain Sprocket................... 28
23 Maintaining and Sharpening the Saw Chain
.................................................................. 29
24 Maintenance and Care..............................33
25 Minimize Wear and Avoid Damage...........34
26 Main Parts.................................................35
27 Specifications............................................36
28 Special Accessories..................................37
29 Ordering Spare Parts................................ 37
30 Maintenance and Repairs......................... 37
31 Disposal.................................................... 37
32 EC Declaration of Conformity................... 38
33 UKCA Declaration of Conformity.............. 38
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 0458-506-0121-C
© ANDREAS STIHL AG & Co. KG 2022
0458-506-0121-C. VA0.B22.
Printed on chlorine-free paper Printing inks contain vegetable oils, paper can be recycled.
Original Instruction Manual 0000008488_006_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
Special safety precautions must be
observed to reduce the risk of per‐
sonal injury when working with a
chain saw 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.
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. Be sure that anyone using it
understands the information contained in this
manual.
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 chain saw.
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 chain saw 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
The chainsaw may be used for cutting wood and
wooden objects only.
Do not the machine for any other purpose – risk
of accidents!
Never attempt to modify your saw 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.
This chainsaw is designed for tree maintenance
work, e.g. pruning small branches. It is therefore
equipped as standard without the spiked
bumper. A spiked bumper (available as special
accessory) may be mounted if required.
When cutting trees with the chain saw, the
spiked bumper must be retrofitted and used.
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 – no loose-fit‐
ting jacket.
Avoid clothing that could get caught on
branches, brush or moving parts of the machine.
Do not wear a scarf, necktie or jewellery. Tie up
2 Safety Precautions English
0458-506-0121-C 3

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 or a face
shield. Make sure that the safety gog‐
gles and the face shield fit correctly.
Wear "personal" hearing protection – for exam‐
ple, ear defenders.
Wear a hard hat wherever there is any risk of
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.
2.4 Transporting
Before any transport – even over short distances
– switch off the machine, engage the chain brake
and attach the chain scabbard. This avoids the
risk of the saw chain starting unintentionally.
0000099161_001
Always carry the chain saw by the handle – with
the hot muffler away from your body, the guide
bar must point to the rear. To avoid serious burn
injuries, avoid touching hot parts of the machine,
especially the surface of the muffler.
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.
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.
English 2 Safety Precautions
4 0458-506-0121-C

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 chain saw
Always work on a level surface. Ensure a firm
and secure footing. Hold the machine securely –
the chain must not touch any objects or the floor
– danger of injury due to the rotating saw chain.
Your chain saw is a one-person saw. Do not
allow other persons to be in the working area –
not even while starting.
Do not start the chain saw if the chain is in a cut.
Move at least 3 meters away from the place
where the machine was refuelled and never start
the motor in enclosed spaces.
Lock the chain with the chain brake before start‐
ing – risk of injury due to rotating chain!
Do not drop-start the engine – start as described
in the Instruction Manual.
2.10 During operation
Ensure you always have a firm and safe footing.
Take special care when the bark is wet – danger
of slipping!
001BA087 LÄ
Always hold the chain saw 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.
In the event of impending danger or in an emer‐
gency, switch off the engine immediately by mov‐
ing the Master Control lever / stop switch to
STOP, 0 or †.
Never let the machine run unattended.
Exercise caution with slippery surfaces, water,
snow, ice, steep slopes, uneven ground or green
wood that has just been stripped of its bark –
danger of slipping!
Use caution with tree stumps, roots, ditches –
danger of stumbling!
Do not work alone – keep within calling distance
of others who are trained in emergency proce‐
dures and can provide help in an emergency.
Helpers at the cutting site must also wear protec‐
tive clothing (helmet!) and stand well clear of the
branches being cut.
More care and attention than usual are required
when wearing ear protection, as warning sounds
(shouts, beeps, etc.) cannot be heard properly.
Take a break in good time to avoid tiredness or
exhaustion – risk of accidents!
Dust (e. g., sawdust), fumes and smoke pro‐
duced while using the machine may be hazard‐
ous to health. If dust is generated, wear a dust
mask.
2 Safety Precautions English
0458-506-0121-C 5

When the engine is running: Note that the saw
chain continues to rotate for a short period after
you let go of the throttle trigger – coasting effect.
No smoking when working with or near the chain
saw - risk of fire! Combustible fuel vapour may
escape from the fuel system.
Examine the saw chain periodically at short inter‐
vals and as soon as you note any tangible
changes:
–Switch off the engine; wait until the saw chain
is stationary
–Check condition and secure fitting
–Check sharpness
Never touch the saw chain when the engine is
running. If the saw chain becomes jammed by an
object, switch off the engine immediately before
attempting to remove the object – risk of injury!
Always turn off the engine before leaving the
machine unattended.
To change the saw chain, switch off the engine.
Risk of injury from the motor starting unintention‐
ally!
Keep easily combustible materials (e. g., wood
chips, bark, dry grass, fuel) away from hot
exhaust gases and hot mufflers – risk of fire!
Mufflers with catalytic converters can become
especially hot.
Never work without chain lubrication – monitor
the oil level in the oil tank. Stop work immediately
if the oil level in the oil tank is too low and top up
with chain oil – see also "Topping up with chain
oil" and "Check chain lubrication".
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 – see also
"Before starting work".
Check the fuel system for leaks and make sure
the safety devices are working properly. Never
continue using a machine 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 saw chain
stops moving when the throttle trigger is
released. Check the idle setting regularly and
correct when possible. Have the machine
repaired by a STIHL servicing dealer if the saw
chain still continues to move during idling.
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.
English 2 Safety Precautions
6 0458-506-0121-C

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).
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.
001BA036 KN
(Kickback) occurs when the saw is suddenly
thrown up and back in an uncontrolled arc
towards the operator.
3 Reactive Forces English
0458-506-0121-C 7

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.
–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 may occur when the chain on the bottom
of the guide bar is suddenly pinched, caught or
encounters a foreign object in the wood. The
reaction of the chain pulls the saw forward –
When working on resistant wood, STIHL recom‐
mends retrofitting with a spiked bumper so that
the motor saw can be positioned safely.
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
3.7 Exercise extreme caution
–with leaners
–with trees that have fallen unfavorably
between other trees and are under strain
–when working in blowdown areas.
In these cases, do not use a chain saw – use a
hoist, winch or drag line instead.
Pull out exposed and cleared logs. Select clear
area for cutting.
Deadwood (dry, decayed or rotted wood) repre‐
sents a considerable risk that is difficult to
assess. Identifying the extent of the dangers is
English 3 Reactive Forces
8 0458-506-0121-C

complicated, if not impossible. Use aids such as
a cable winch or tractor in such cases.
When felling in the vicinity of roads, railways,
power lines, etc., take extra precautions. If nec‐
essary, inform the police, utility company or rail‐
way authority.
4 Working Techniques
Sawing and felling work, including all related
work (plunge cutting, limbing, etc.) may only be
carried out by persons who have been specially
trained and instructed. Persons who are not
experienced chain saw users should not carry
out any such work – increased risk of accidents!
Country-specific legislation on felling technique
must be complied with during felling work.
4.1 Sawing
Do not operate your saw with the starting throttle
lock engaged. Engine speed cannot be control‐
led 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.
It is advisable for first-time users to practice cut‐
ting logs on a sawbuck – see "Sawing thin
wood".
Use the shortest possible guide bar: The chain,
guide bar and chain sprocket must match each
other and your saw.
001BA082 KN
Position the saw so that your body is clear of the
cutting attachment.
Always pull the saw out of the cut with the chain
running.
Use your chain saw for cutting only. It is not
designed for prying or shoveling away limbs,
roots or other objects.
Do not underbuck freely hanging limbs.
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!
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. Dried-out plants and undergrowth are
combustible, especially 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 current fire haz‐
ards.
001BA033 KN
If on a slope, stand on the uphill side of the log.
Watch out for rolling logs.
When Working at Height:
–Always use a lift bucket
–Never use the machine while standing on a
ladder or in a tree
–Never work on an insecure support
–Never work above shoulder height
–Never use the machine with just one hand
Begin cutting with the chainsaw at full throttle.
For work other than arboriculture, STIHL recom‐
mends retrofitting with a spiked bumper so that
the chainsaw can be positioned safely.
At the end of the cut, the chainsaw is no longer
supported by the cutting attachment in the cut.
The chain saw's weight must be borne by the
user – risk of loss of control!
Sawing thin wood:
–Use a sturdy and stable support – sawhorse.
–Never hold the log with your leg or foot.
4 Working Techniques English
0458-506-0121-C 9

–never allow another person to hold the log or
help in any other way.
Limbing
–use a low kickback chain.
–Work with the saw supported wherever possi‐
ble.
–do not stand on the log while limbing it.
–do not cut with the bar nose.
–watch for limbs which are under tension.
–never cut several limbs at once.
Lying or standing logs under tension:
Always make the cuts in the correct order (first
compression side (1), then tension side (2)), oth‐
erwise the cutting attachment may stick in the cut
or kick back – risk of injury!
1
001BA151 KN
2
1
001BA152 KN
2
► Make relieving cut at the compression side (1)
► Make bucking cut at the tension side (2)
Be wary of pushback when making bucking cut
from the bottom upwards (underbuck).
NOTICE
Do not cut a lying log at a point where it is touch‐
ing the ground because the saw chain will other‐
wise be damaged.
Ripping:
001BA189 KN
Sawing technique without use of the spiked
bumper – risk of pull-in – position the guide bar at
as shallow an angle as possible – be especially
careful – increased risk of kickback!
4.2 Preparing for felling
Check that there are no other persons in the fell‐
ing area – other than helpers.
Make sure no-one is endangered by the falling
tree – the noise of your engine may drown any
warning calls.
001BA088 LÄ
2
/
12
11
/
12
Maintain a distance of at least 2 1/2 tree lengths
from the next felling site.
Determining direction of fall and escape path
Select gap in stand into which you want the tree
to fall.
Pay special attention to the following points:
–The natural inclination of the tree
–Unusually heavy limb structure, asymmetrical
growth, damage to tree
–The wind direction and speed – do not fell in
high winds
–Direction of slope
–Neighboring trees
–Snow load
–Take the general condition of the tree into
account – be especially careful with trunk
damage or deadwood (brittle, rotten or dead
wood)
English 4 Working Techniques
10 0458-506-0121-C

001BA040 KN
B
B
A Direction of fall
B Escape path (escape routes)
–Establish escape paths for each worker –
approx. 45° diagonally opposite to the direc‐
tion of fall
–Clear escape paths, eliminate obstacles
–Put down tools and equipment at a safe dis‐
tance – but not on the escape paths
–When felling, stand only to the side of the fall‐
ing trunk and only move back laterally onto the
escape path
–Plan escape paths on slopes parallel to the
slope
–When walking away along the escape path,
watch out for falling limbs and watch the top of
the tree.
Preparing work area at base of tree
–First clear the tree base and work area from
interfering limbs and brush to provide a secure
footing.
–Carefully clear the base of the trunk (e.g., with
an axe) – sand, stones and other foreign
objects will blunt the saw chain
001BA146 KN
–Remove largest buttresses: first the largest
buttress – saw first vertically, then horizontally
– only if the tree is in sound condition
4.3 Felling notch
Preparing the felling notch
001BA271 KN
C
C
The felling notch (C) determines the direction of
fall.
Important:
–Make a felling notch at right angle to direction
of fall
–Saw as close to the ground as possible
–Cut to a depth of approx. 1/5 to 1/3 of the
diameter of the trunk
Specify the direction of fall – without the gunning
sight on the shroud and fan housing
If the chain saw is designed without the gunning
sight on the shroud and fan housing, the direc‐
tion of fall can be determined or controlled using
a meter stick:
001BA246 KN
► Snap the meter stick in the middle and create
an isosceles triangle
► Position both ends of the meter stick in the
front trunk area (1/5 to max. 1/3 of the trunk
diameter) – align the tip of the meter stick in
the defined direction of fall
► Mark the trunk at both ends of the meter stick
to limit the felling notch
4 Working Techniques English
0458-506-0121-C 11

Making the felling notch
001BA247 KN
When making a felling notch, align the chainsaw
so that the notch lies at a right angle to the direc‐
tion of fall.
During the procedure, various sequences are
permitted for making a felling notch with a bottom
(horizontal) cut and top (angled) cut – comply
with national legislation regarding felling techni‐
que.
► Make the bottom cut (horizontal cut) – until the
guide bar reaches both markings
► Make the top (angled) cut approx. 45°‑ 60° to
the bottom cut
Checking the direction of fall
The bottom cut and top cut must meet in a con‐
tinuous straight sink chord.
001BA243 KN
► Position the meter stick at the pivot point of
the sink chord – the tip of the meter stick must
point in the direction of the specified direction
of fall – where necessary, correct the direction
of fall by cutting the felling notch accordingly
4.4 Sapwood cuts
001BA150 KN
Sapwood cuts in long-fibered softwood help pre‐
vent sapwood splintering when the tree falls.
Make cuts at both sides of the trunk at same
height as bottom of felling notch to a depth of
about 1/10 of trunk diameter. On large diameter
trees, cut to no more than width of guide bar.
Do not make sapwood cuts if wood is diseased.
4.5 Basic information on felling cut
Basic dimensions
001BA259 KN
G
E
C
C
Ø
1/10
The felling notch (C) determines the direction of
fall.
The hinge (D) functions like a real hinge to guide
the tree to the ground.
–Width of hinge: approx. 1/10 of the trunk diam‐
eter
–Never saw through the hinge while felling –
otherwise the tree will fall in a direction other
than the one planned – risk of accident!
–With rotten trunks, leave a wider hinge
The tree is felled with the felling cut (E).
–Cut horizontally
–1/10 (min. 3 cm) of the width of the hinge (D)
across the bottom of the felling notch (C)
The holding wood (F) or safety strip (G) supports
the tree and secures it against premature falling.
–Width of strip: approx. 1/10 to 1/5 of the trunk
diameter
–Do not cut into the strip during the felling cut
–With rotten trunks, leave a wider strip
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Plunge cutting
–For relieving cuts during shortening
–For wood carving
001BA269 KN
3.
1.
2.
► Use a low kickback saw chain and proceed
with special care
1. Begin cut by applying the lower portion of the
guide bar nose – do not use upper portion
because of risk of kickback. Cut at full
strength until the depth of the kerf is twice
the width of the guide bar
2. Swing the machine slowly into the plunge
cutting position – risk of kickback and push‐
back!
3. Make the plunge cut very carefully. Risk of
pushback.
001BA270 KN
Where possible, use a plunge blade. The plunge
blade and the upper/lower side of the guide bar
are parallel.
During plunge cutting, the plunge bar helps to
keep the hinge parallel in form, i.e. the same
thickness at all points. To do this, guide the
plunge bar parallel to the sink chord.
Felling wedges
Insert the felling wedge as soon as possible, i.e.
as soon as no obstruction of saw control is to be
expected. Position the felling wedge in the felling
cut and drive in with suitable tools.
Only use aluminum or plastic wedges – do not
use steel wedges. Steel wedges can seriously
damage the saw chain and cause dangerous
kickback.
Select suitable felling wedges dependent on the
trunk diameter and the width of the kerf (ana‐
logue to felling cut (E)).
Contact the STIHL dealer for the selection of the
felling wedge (suitable length, width and height).
4.6 Selecting the appropriate felling
cut
The selection of the appropriate felling cut is
dependent on the same tree characteristics that
must be noted when determining the direction of
fall and the escape paths.
There are various different features of these
characteristics. This User Manual will only
describe the two most commonly occurring var‐
iants:
001BA260 KN
left: Normal tree – vertically upright tree
with uniform crown
right: Leaner tree - crown pointing in direc‐
tion of fall
4.7 Felling cut with stabilizing strap
(normal tree)
A) Thin trunks
Implement this felling cut when the trunk diame‐
ter is smaller than the cutting length of the chain‐
saw.
001BA261 KN
1.
2.
4 Working Techniques English
0458-506-0121-C 13

Shout a warning before starting the felling cut.
► Plunge cut the felling cut (E) – plunge the
guide bar fully in
► Engage the spiked bumper behind the hinge
and use this as the rotation point – reposition
the chainsaw as little as possible
► Make the felling cut up to the hinge (1)
–Do not cut into the hinge
► Make the felling cut up to the stabilizing
strap (2)
–Do not cut into the stabilizing strap
001BA273 KN
3.
► Set the felling wedge (3)
Shout a second warning immediately before the
tree falls.
► Cut through the stabilizing strap, horizontal
level with the felling cut, with arms fully exten‐
ded
B) Thick trunks
Implement this felling cut when the trunk diame‐
ter is greater than the cutting length of the
machine.
001BA263 KN
4. 5.
1.
2. 3.
Shout a warning before starting the felling cut.
► Engage the spiked bumper at the height of the
felling cut and use this as the rotation point –
reposition the chainsaw as little as possible
► Tip of the guide bar must penetrate the wood
before the hinge (1) – guide the chainsaw
absolutely horizontally and swivel as widely as
possible
► Make the felling cut up to the hinge (2)
–Do not cut into the hinge
► Make the felling cut up to the stabilizing
strap (3)
–Do not cut into the stabilizing strap
The felling cut must be continued on the oppo‐
site side of the trunk.
Ensure that the second cut is at the same level
as the first cut.
► Plunge cut the felling cut
► Make the felling cut up to the hinge (4)
–Do not cut into the hinge
► Make the felling cut up to the stabilizing
strap (5)
–Do not cut into the stabilizing strap
001BA274 KN
6.
► Set the felling wedge (6)
Shout a second warning immediately before the
tree falls.
► Cut through the stabilizing strap, horizontal
level with the felling cut, with arms fully exten‐
ded
4.8 Felling Cut with Holding Strap
(Leaner)
A) Thin trunks
Implement this felling cut when the trunk diame‐
ter is smaller than the cutting length of the chain‐
saw.
001BA265 KN
1. 2.
► Plunge cut the guide bar into the trunk until it
exits on the other side
► Make the felling cut (E) towards the hinge (1)
–Cut horizontally
–Do not cut into the hinge
English 4 Working Techniques
14 0458-506-0121-C

► Make the felling cut towards the holding strap
(2)
–Cut horizontally
–Do not cut into the holding strap.
001BA266 KN
Shout a second warning immediately before the
tree falls.
► With outstretched arms, cut through the hold‐
ing strap at a downward angle from outside.
B) Thick trunks
001BA267 KN
1.
2. 3.
4.
5. 6.
Perform this felling cut when the tree diameter is
greater than the cutting length of the chainsaw.
► Engage the bumper spike behind the holding
wood and use this as the rotation point – repo‐
sition the chain saw as little as possible
► The guide bar nose enters the wood (1) before
it reaches the hinge – hold the chainsaw hori‐
zontally and swing it as far as possible.
–Do not cut into the holding strap or hinge.
► Make the felling cut up to the hinge (2)
–Do not cut into the hinge
► Make the felling cut up to the holding strap (3)
–Do not cut into the holding strap.
The felling cut must be continued on the oppo‐
site side of the trunk.
Ensure that the second cut is at the same level
as the first cut.
► Engage the spiked bumper behind the hinge
and use this as the rotation point – reposition
the chainsaw as little as possible
► Tip of the guide bar must penetrate the wood
before the holding strap (4) – guide the chain‐
saw absolutely horizontally and swivel as
widely as possible
► Make the felling cut up to the hinge (5)
–Do not cut into the hinge
► Make the felling cut up to the holding strap (6)
–Do not cut into the holding strap.
001BA268 KN
Shout a second warning immediately before the
tree falls.
► With outstretched arms, cut through the hold‐
ing strap at a downward angle from outside.
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.
5 Cutting Attachment English
0458-506-0121-C 15

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 Disengaging the chain brake
2011BA001 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
2011BA002 KN
2
► Unscrew the nut (1) and remove the chain
sprocket cover (2)
6.3 Mounting the Guide Bar
2011BA003 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
2011BA004 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!
2011BA005 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
English 6 Mounting the Bar and Chain
16 0458-506-0121-C

2
2011BA006 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
2011BA007 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
2011BA008 KN
Retensioning during cutting work:
► Shut down 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
2011BA009 KN
► Shut down 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
The engine requires a mixture of gasoline and
engine oil.
WARNING
Avoid direct skin contact with fuel and breathing
in of gasoline fumes.
9.1 STIHL MotoMix
STIHL recommends using STIHL MotoMix. This
pre-blended fuel is free of benzene and lead, is
distinguished by a high octane rating, and
always provides the proper mixing ratio.
STIHL MotoMix uses STIHL HP Ultra two-stroke
engine oil for optimum engine life.
MotoMix is not available in all markets.
7 Tensioning the Saw Chain (side chain tensioner) English
0458-506-0121-C 17

9.2 Mixing fuel
NOTICE
Unsuitable fuels or a mixing ratio that deviates
from the specification can lead to severe engine
damage. The engine, seals, fuel lines and fuel
tank may be damaged if low-quality gasoline or
engine oil is used.
9.2.1 Gasoline
Use only high-quality gasoline with an octane rat‐
ing of at least 90 ROC – leaded or unleaded.
Gasoline with an alcohol component exceeding
10% can cause impaired engine performance in
engines with manually adjustable carburetors
and thus should not be used in these engines.
Engines with M-Tronic deliver full engine per‐
formance using gasoline with an alcohol compo‐
nent of up to 27% (E27).
9.2.2 Engine oil
If you mix the fuel yourself, use only STIHL two-
stroke engine oil or another high-performance
engine oil classified as 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 Mixing ratio
with STIHL two-stroke engine oil 1:50; 1:50 =
1 part oil + 50 parts gasoline
9.2.4 Examples
Quantity of gaso‐
line
STIHL two-stroke
engine oil 1:50
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)
► Pour oil into an approved safety fuel canister
first, then add gasoline and mix thoroughly
9.3 Storing fuel mixture
Store in approved safety fuel canisters only in a
dry, cool and secure place protected against light
and sunlight.
Fuel mixture deteriorates with age – mix only as
much as needed for a few weeks. Do not store
fuel mixture for longer than 30 days. The fuel
mixture can become unusable more quickly if
exposed to light, sunlight or low or high tempera‐
tures.
STIHL MotoMix however can be stored for up to
5 years without any problems.
► Shake the canister containing the fuel mixture
thoroughly before refueling
WARNING
Pressure may have built up in the canister –
open it carefully.
► The fuel tank and the canister in which fuel
mixture is stored should be cleaned thoroughly
from time to time
Residual fuel and the liquid used for cleaning
must be disposed of in accordance with regula‐
tions and without harming the environment!
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.
English 10 Fueling
18 0458-506-0121-C

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.
10 Fueling English
0458-506-0121-C 19

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.
English 11 Chain Lubricant
20 0458-506-0121-C