STIHL MS 291, MS 291 C-BEQ, MS 271 Owner's Manual
STIHL MS 271, 291
{
Instruction Manual
Manual de instrucciones
Warning!
To reduce the risk of kickback injury use
STIHL reduced kickback bar and STIHL
26 RMC3 (.325") chain depending on sprocket
pitch or other available low kickback
components.
Advertencia!
Para reducir el riesgo de lesionarse como
resultado de un culatazo, utilice la barra de
contragolpe reducido y la cadena
26 RMC3 (.325 pulg) de STIHL, dependiendo
de la rueda dentada usada y de otros
componentes reductores de contragolpe.
Read and follow all safety precautions in
Instruction Manual – improper use can cause
serious or fatal injury.
Lea y siga todas las precauciones de
seguridad dadas en el manual de
instrucciones – el uso incorrecto puede causar
lesiones graves o mortales.
Instruction Manual
1 - 60
Manual de
instrucciones
61 - 125
Contents
English
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 3
Cutting Attachment 24
Mounting the Bar and Chain (side
chain tensioner) 24
Mounting the Bar and Chain (quick
chain tensioner) 25
Tensioning the Saw Chain (side
Original Instruction ManualPrinted on chlorine-free paper
chain tensioner) 27
Tensioning the Saw Chain (quick
chain tensioner) 27
Checking Chain Tension 28
Fuel 28
Fueling 29
Chain Lubricant 31
Filling Chain Oil Tank 31
Checking Chain Lubrication 32
Chain Brake 32
Winter Operation 33
Starting / Stopping the Engine 34
Operating Instructions 37
Taking Care of the Guide Bar 38
Printing inks contain vegetable oils, paper can be recycled.
Shroud 39
Air Filter System 39
Cleaning the Air Filter 40
Engine Management 40
Adjusting the Carburetor 41
Spark Arresting Screen in Muffler 42
Spark Plug 42
Replacing the Starter Rope and
Rewind Spring 43
Storing the Machine 46
Checking and Replacing the Chain
Sprocket 46
Maintaining and Sharpening the
Saw Chain 47
Maintenance and Care 51
Main Parts 53
Specifications 55
Special Accessories 56
Ordering Spare Parts 57
Maintenance and Repairs 57
STIHL Incorporated Federal
Emission Control Warranty
Statement 57
Trademarks 59
Allow only persons who fully understand
this manual to operate your chain saw.
To receive maximum performance and
satisfaction from your STIHL chain saw,
it is important that you read, understand
and follow the safety precautions and
the operating and maintenance
instructions in chapter "Safety
Precautions and Working Techniques"
before using your chain saw. For further
information you can go to
www.stihlusa.com.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
Warning!
Because a chain saw is a high-speed
wood-cutting tool, some special safety
precautions must be observed as with
any other power saw to reduce the risk
of personal injury. Careless or improper
use may cause serious or even fatal
injury.
{
© ANDREAS STIHL AG & Co. KG, 2011
0458-574-8621-A. M3-2.B11.PM.
0000003104_002_GB
MS 271, MS 291, MS 291 C
1
English
Guide to Using this Manual
Pictograms
The meanings of the pictograms
attached to or embossed on the
machine are explained in this manual.
Depending on the model concerned, the
following pictograms may be on your
machine.
Fuel tank; fuel mixture of
gasoline and engine oil
Chain oil tank; chain oil
Engaging and disengaging the STIHL Quickstop
chain brake
Direction of chain rotation
Ematic; chain oil quantity
control
Tension the chain
Intake air preheating for
winter operation
Intake air for summer
operation
Handle heating
Operate decompression
valve
Operate manual fuel
pump
Symbols in Text
Many operating and safety instructions
are supported by illustrations.
The individual steps or procedures
described in the manual may be marked
in different ways:
N A bullet marks a step or procedure.
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration. Example:
N Loosen the screw (1).
N Lever (2) ...
In addition to the operating instructions,
this manual may contain paragraphs
that require your special attention. Such
paragraphs are marked with the
symbols and signal words described
below:
Danger!
Indicates an imminent risk of severe or
fatal injury.
Warning!
Indicates a hazardous situation which, if
not avoided, could result in severe or
fatal injury.
Caution!
Indicates a risk of property damage,
including damage to the machine or its
individual components.
Engineering Improvements
STIHL’s philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time to time. Therefore,
some changes, modifications and
improvements may not be covered in
this manual. If the operating
characteristics or the appearance of
your machine differs from those
described in this manual, please contact
your STIHL dealer for assistance.
2
MS 271, MS 291, MS 291 C
English
Safety Precautions and
Working Techniques
Because a chain saw is a
high-speed, fast-cutting
power tool, special safety
precautions must be
observed to reduce the
risk of personal injury.
It is important that you
read, fully understand
and observe the following
safety precautions and
warnings. Read the
instruction manual and
the safety instructions
periodically. Careless or
improper use may cause
serious or fatal injury.
Warning!
Reactive forces, including kickback, can
be dangerous. Pay special attention to
the section on reactive forces.
Have your STIHL dealer show you how
to operate your power tool. All safety
precautions that are generally observed
when working with an ax or a hand saw
also apply to the operation of chain
saws. Observe all applicable federal,
state and local safety regulations,
standards and ordinances. When using
a chain saw for logging purposes, for
instance, refer to the OSHA regulations
for "logging operations" at 29 Code of
Federal Regulations 1910.266.
Warning!
Do not lend or rent your power tool without the instruction manual. Be sure that
anyone using it understands the information contained in this manual.
Warning!
The use of this machine may be hazardous.The saw chain has many sharp
cutters. If the cutters contact your flesh,
they will cut you, even if the chain is not
moving.
Use your chain saw only for cutting
wooden objects.
Warning!
Do not use it for other purposes, since
misuse may result in personal injury or
property damage, including damage to
the machine
Warning!
Minors should never be allowed to use
this power tool. Bystanders, especially
children, and animals should not be
allowed in the area where it is in use.
Warning!
To reduce the risk of injury to bystanders and damage to property, never let
your power tool run unattended. When it
is not in use (e.g. during a work break),
shut it off and make sure that unauthorized persons do not use it.
Most of these safety precautions and
warnings apply to the use of all STIHL
chain saws. Different models may have
different parts and controls. See the
appropriate section of your instruction
manual for a description of the controls
and the function of the parts of your
model.
Safe use of a chain saw involves
1 the operator
2 the power tool
3 the use of the power tool.
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.
Warning!
Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition
that might be aggravated by strenuous
work, check with your doctor before
operating this machine.
Warning!
Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
MS 271, MS 291, MS 291 C
3
English
These conditions reduce the hand's
ability to feel and regulate temperature,
produce numbness and burning
sensations and may cause nerve and
circulation damage and tissue necrosis.
All factors which contribute to whitefinger disease are not known, but cold
weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
disease. In order to reduce the risk of
whitefinger disease and carpal tunnel
syndrome, please note the following:
– Most STIHL power tools are
available with an anti-vibration
("AV") system designed to reduce
the transmission of vibrations
created by the machine to the
operator's hands. An AV system is
recommended for those persons
using power tools on a regular or
sustained basis.
– Wear gloves and keep your hands
warm. Heated handles, which are
available on some STIHL
powerheads, are recommended for
cold weather use.
– Keep the AV system well
maintained. A power tool with loose
components or with damaged or
worn AV elements will tend to have
higher vibration levels. Keep the
saw chain sharp. A dull chain will
increase cutting time, and pressing
a dull chain through wood will
increase the vibrations transmitted
to your hands.
– Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressure. Take
frequent breaks.
All the above-mentioned precautions do
not guarantee that you will not sustain
whitefinger disease or carpal tunnel
syndrome. Therefore, continual and
regular users should closely monitor the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
Warning!
The ignition system of the STIHL unit
produces an electromagnetic field of a
very low intensity. This field may interfere with some pacemakers. To reduce
the risk of serious or fatal injury, persons
with a pacemaker should consult their
physician and the pacemaker manufacturer before operating this tool.
Proper Clothing
Warning!
To reduce the risk of injury, the operator
should wear proper protective apparel.
Clothing must be sturdy
and snug-fitting, but allow
complete freedom of
movement. Wear long
pants made of heavy
material to help protect
your legs from contact
with branches or brush.
To reduce the risk of cut
injuries, wear pants or
chaps that contain pads
of cut retardant material.
Avoid loose-fitting jackets, scarfs, neckties,
jewelry, flared or cuffed
pants, unconfined long
hair or anything that
could become caught on
branches, brush or the
moving parts of the unit.
Secure hair so it is above
shoulder level.
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended.
Wear an approved safety
hard hat to reduce the
risk of injury to your head.
Chain saw noise may
damage your hearing.
Wear sound barriers (ear
plugs or ear mufflers) to
help protect your hearing.
Continual and regular
users should have their
hearing checked
regularly.
4
MS 271, MS 291, MS 291 C
English
001BA115 KN
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
Never operate your power tool unless
wearing goggles or properly fitted
protective glasses with adequate top
and side protection complying with ANSI
Z 87.1 (or your applicable national
standard). To reduce the risk of injury to
your face STIHL recommends that you
also wear a face shield or face screen
over your goggles or protective glasses.
Always wear gloves
when handling the
machine and the cutting
tool. Heavy-duty, nonslip
gloves improve your grip
and help to protect your
hands.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts."
Warning!
Never modify this power tool in any way.
Only attachments supplied by STIHL or
expressly approved by STIHL for use
with the specific STIHL model are
authorized. Although certain unauthorized attachments are useable with
STIHL power tools, their use may, in
fact, be extremely dangerous.
If this tool is subjected to unusually high
loads for which it was not designed (e.g.
heavy impact or a fall), always check
that it is in good condition before
continuing work. Check in particular that
the fuel system is tight (no leaks) and
that the controls and safety devices are
working properly. Do not continue
operating this machine if it is damaged.
In case of doubt, have it checked by your
STIHL servicing dealer.
THE USE OF THE POWER TOOL
Transporting the Power Tool
Warning!
To reduce the risk of injury from saw
chain contact, never carry or transport
your power tool with the saw chain moving. Always engage the chain brake
when taking more than a few steps.
Warning!
Always switch off the engine, and fit the
chain guard (scabbard) over the chain
and guide bar before transporting the
power tool over longer distances. When
transporting it in a vehicle, properly
secure it to prevent turnover, fuel spillage and damage to the unit.
It may be carried only in a horizontal
position. Grip the front handle in a
manner that the machine is balanced
horizontally. Keep the hot muffler away
from your body and the cutting
attachment behind you.
Fuel
Your STIHL power tool uses an oilgasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual).
Warning!
Gasoline is an extremely
flammable fuel. If spilled
and ignited by a spark or
other ignition source, it
can cause fire and seri-
ous burn injury or
property damage. Use extreme caution
when handling gasoline or fuel mix. Do
not smoke or bring any fire or flame near
the fuel or the power tool. Note that
combustible fuel vapor may escape
from the fuel system.
Fueling Instructions
Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before refueling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
In order to reduce the risk of burns and
other personal injury from escaping gas
vapor and fumes, remove the fuel filler
cap on your power tool carefully so as to
allow any pressure build-up in the tank
to release slowly. Never remove the fuel
filler cap while the engine is running.
MS 271, MS 291, MS 291 C
5
English
001BA220 KN
001BA227 KN
001BA226 KN
Select bare ground for fueling and move
at least 10 feet (3 m) from the fueling
spot before starting the engine. Wipe off
any spilled fuel before starting your
machine.
Warning!
Check for fuel leakage
while refueling and during operation. If fuel
leakage is found, do not
start or run the engine
until the leak is fixed and
any spilled fuel has been wiped away.
Take care not to get fuel on your clothing. If this happens, change your
clothing immediately.
Different models may be equipped with
different fuel caps.
Toolless cap with grip
Warning!
In order to reduce the risk of fuel spillage and fire from an improperly
tightened fuel cap, correctly position
and tighten the fuel cap in the fuel tank
opening.
marks on the grip of the cap and on the
fuel tank opening lining up. Using the
grip, press the cap down firmly while
turning it clockwise as far as it will go
(approx. 1/4 turn).
Fold the grip flush with
the top of the cap. Grip
the cap and check for
tightness. If the grip does
not lie completely flush
with the cap and the
detent on the grip does
not fit in the corresponding recess in the filler
opening, or if the cap is
loose in the filler opening,
the cap is not properly
seated and tightened and
you must repeat the
above steps.
Misaligned, damaged or broken cap
N If the cap does not drop fully into the
opening when the positioning marks
line up and/or if the cap does not
tighten properly when twisted, the
base of the cap may be prematurely
rotated (in relation to the top) to the
closed position. Such misalignment
can result from handling, cleaning
or an improper attempt at
tightening.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
N To return the cap to the open
position for installation, turn the cap
(with the grip up) until it drops fully
into the tank opening. Next, twist the
cap counterclockwise as far as it will
go (approx. 1/4 turn) – this will twist
the base of the cap into the correct
position. Then, twist the cap
clockwise, closing it normally.
N If your cap still does not tighten
properly, it may be damaged or
broken; immediately stop use of the
unit and take it to your authorized
STIHL dealer for repair.
To do this with this STIHL cap, raise the
grip on the top of the cap until it is upright
at a 90° angle. Insert the cap in the fuel
tank opening with the raised positioning
6
MS 271, MS 291, MS 291 C
Screw Cap
Warning!
Unit vibrations can
cause an improperly
tightened fuel filler cap to
loosen or come off and
spill quantities of fuel. In
order to reduce the risk
of fuel spillage and fire, tighten the fuel
filler cap by hand as securely as
possible.
The screwdriver end of the STIHL
combination wrench or other similar tool
can be used as an aid in tightening
slotted fuel filler caps.
See also the "Fueling" chapter in your
Instruction Manual for additional
information.
Before Starting
Take off the chain guard (scabbard) and
inspect the saw for proper condition and
operation. (See the maintenance chart
near the end of the instruction manual.)
Warning!
Never operate your power tool if it is
damaged, improperly adjusted or maintained, or not completely or securely
assembled.
Warning!
Check that the spark plug boot is
securely mounted on the spark plug – a
loose boot may cause arcing that could
ignite combustible fumes and cause a
fire.
For proper assembly of the bar and
chain follow the procedure described in
the chapter "Mounting the Bar and
Chain" of your instruction manual.
STIHL Oilomatic chain, guide bar and
sprocket must match each other in
gauge and pitch. Before replacing any
bar and chain, see the chapter entitled
"Specifications" in the instruction
manual and the section "Kickback" and
the "ANSI B 175.1-2000 chain saw
chain saw kickback standard" below.
English
Warning!
Proper tension of the chain is extremely
important. In order to avoid improper
setting, the tensioning procedure must
be followed as described in your manual. Always make sure the hexagonal
nut(s) for the sprocket cover is (are)
tightened securely after tensioning the
chain in order to secure the bar. Never
start the saw with the sprocket cover
loose. Check chain tension once more
after having tightened the nut(s) and
thereafter at regular intervals (whenever
the saw is shut off). If the chain
becomes loose while cutting, shut off
the engine and then tighten. Never try to
adjust the chain while the engine is
running!
Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, fuel mix,
grease or resin in order for you to
maintain a firm grip and properly control
your power tool.
Starting
Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger lockout, stop switch and cutting
tool. The throttle trigger must move
freely and always spring back to the idle
position. Never attempt to modify the
controls or safety devices.
MS 271, MS 291, MS 291 C
Warning!
To reduce the risk of fire and burn injuries, start the engine at least 10 feet
(3 m) from the fueling spot, outdoors
only.
Start and operate your saw without
assistance. For specific starting
instructions, see the appropriate section
of the instruction manual. Proper starting
methods reduce the risk of injury.
7
English
001BA113 KN
001BA114 KN
Warning!
To reduce the risk of injury from chain
contact and / or reactive forces, the
chain brake must be engaged when
starting the saw.
Warning!
Do not drop start. This method is very
dangerous because you may lose control of the saw.
There are two recommended methods
for starting your chain saw.
With the first recommended method,
the chain saw is started on the ground.
Make sure the chain brake is engaged
(see "Chain Brake" chapter in your
instruction manual) and place the chain
saw on firm ground or other solid surface
in an open area. Maintain good balance
and secure footing.
Grip the front handlebar of the saw firmly
with your left hand and press down. For
saws with a rear handle level with the
ground, put the toe of your right foot into
the rear handle and press down. With
your right hand pull out the starter grip
slowly until you feel a definite resistance
and then give it a brisk, strong pull.
The second recommended method for
starting your chain saw allows you to
start the saw without placing it on the
ground. Make sure the chain brake is
engaged, grip the front handle of the
chain saw firmly with your left hand.
Keep your arm on the front handle in a
locked (straight) position. Hold the rear
handle of the saw tightly between your
legs just above the knees. Maintain
good balance and secure footing. Pull
the starting grip slowly with your right
hand until you feel a definite resistance
and then give it a brisk, strong pull.
Warning!
Be sure that the guide bar and chain are
clear of you and all other obstructions
and objects, including the ground. When
the engine is started, the engine speed
with the starting throttle lock engaged
will be fast enough for the clutch to
engage the sprocket and, if the chain
brake is not activated, turn the chain. If
the upper quadrant of the tip of the bar
touches any object, it may cause kickback to occur (see section on reactive
forces). To reduce this risk, always
engage the chain brake before starting.
Never attempt to start the chain saw
when the guide bar is in a cut or kerf.
As soon as the engine is running,
immediately blip the throttle trigger,
which will disengage the starting throttle
lock and allow the engine to settle down
to idle.
Warning!
When you pull the starter grip, do not
wrap the starter rope around your hand.
Do not let the grip snap back, but guide
the starter rope to rewind it properly.
Failure to follow this procedure may
result in injury to your hand or fingers
and may damage the starter
mechanism.
Important Adjustments
Warning!
To reduce the risk of personal injury
from loss of control and / or contact with
the running cutting tool, do not use your
unit with incorrect idle adjustment. At
correct idle speed, the cutting tool
should not move. For directions on how
to adjust idle speed, see the appropriate
section of your instruction manual.
If you cannot set the correct idle speed,
have your STIHL dealer check your
power tool and make proper
adjustments and repairs.
During Operation
Holding and Controlling the Power
Tool
Always hold the unit firmly with both
hands on the handles while you are
working. Wrap your fingers and thumbs
around the handles.
8
MS 271, MS 291, MS 291 C
Your right hand should grip the rear
001BA087 LÄ
001BA031 KN
handle. This also applies to left-handers.
With your hands in this position, you can
best oppose and absorb the push, pull
and kickback forces of your saw without
losing control (see section on reactive
forces).
Warning!
To reduce the risk
of serious or fatal
injury to the operator or bystanders
from loss of control, never use the saw with one hand. It
is more difficult for you to control reactive forces and to prevent the bar and
chain from skating or bouncing along
the limb or log. Even for those compact
saws designed for use in confined
spaces, one-handed operation is dangerous because the operator may lose
control.
Warning!
To reduce the risk of cut injuries, keep
hands and feet away from the cutting
tool. Never touch a moving cutting tool
with your hand or any other part of your
body.
Warning!
Keep proper footing and balance at all
times. Special care must be taken in
slippery conditions (wet ground, snow)
and in difficult, overgrown terrain. Watch
for hidden obstacles such as tree
stumps, roots, rocks, holes and ditches
to avoid stumbling. There is increased
danger of slipping on freshly debarked
logs. For better footing, clear away
fallen branches, scrub and cuttings. Be
extremely cautious when working on
slopes or uneven ground.
Warning!
Take extreme care in wet and freezing
weather (rain, snow, ice). Put off the
work when the weather is windy, stormy
or rainfall is heavy.
English
Warning!
To reduce the risk of injury from loss of
control, never work on a ladder or any
other insecure support. Never hold the
machine above shoulder height. Do not
overreach.
Warning!
Never work in a tree unless you have
received specific, professional training
for such work, are properly secured
(such as tackle and harness system or a
lift bucket), have both hands free for
operating the chain saw in a cramped
environment and have taken proper precautions to avoid injury from falling
limbs or branches.
MS 271, MS 291, MS 291 C
9
English
001BA082 KN
Position the chain saw in such a way
that your body is clear of the cutting
attachment whenever the engine is
running. Stand to the left of cut while
bucking.
Never put pressure on the saw when
reaching the end of a cut. The pressure
may cause the bar and rotating chain to
pop out of the cut or kerf, go out of
control and strike the operator or some
other object. If the rotating chain strikes
some other object, a reactive force may
cause the moving chain to strike the
operator.
Working Conditions
Operate and start your power tool only
outdoors in a well ventilated area.
Operate it under good visibility and
daylight conditions only. Work carefully.
Warning!
Your chain saw is a one-person
machine. Do not allow other persons in
the general work area, even when starting. Stop the engine immediately if you
are approached.
Warning!
Even though bystanders should be kept
away from the running saw, never work
alone. Keep within calling distance of
others in case help is needed.
Warning!
As soon as the engine is
running, this product
generates toxic exhaust
fumes containing chemicals, such as unburned
hydrocarbons (including
benzene) and carbon monoxide, that
are known to cause respiratory problems, cancer, birth defects, or other
reproductive harm. Some of the gases
(e.g. carbon monoxide) may be colorless and odorless. To reduce the risk of
serious or fatal injury / illness from inhaling toxic fumes, never run the machine
indoors or in poorly ventilated locations.
If exhaust fumes become concentrated
due to insufficient ventilation, clear
obstructions from work area to permit
proper ventilation before proceeding
and / or take frequent breaks to allow
fumes to dissipate before they become
concentrated.
Warning!
Inhalation of certain dusts, especially
organic dusts such as mold or pollen,
can cause susceptible persons to have
an allergic or asthmatic reaction. Substantial or repeated inhalation of dust
and other airborne contaminants, in particular those with a smaller particle size,
may cause respiratory or other illnesses. This includes wood dust,
especially from hardwoods, but also
from some softwoods such as Western
Red Cedar. Control dust at the source
where possible. Use good work practices, such as always cutting with a
properly sharpened chain (which produces wood chips rather than fine dust)
and operating the unit so that the wind
or operating process directs any dust
raised by the power tool away from the
operator. Follow the recommendations
of EPA / OSHA / NIOSH and occupational and trade associations with
respect to dust ("particulate matter").
When the inhalation of dust cannot be
substantially controlled, i.e., kept at or
near the ambient (background) level,
the operator and any bystanders should
wear a respirator approved by NIOSH /
MSHA for the type of dust encountered.
10
MS 271, MS 291, MS 291 C
Warning!
Breathing asbestos dust is dangerous
and can cause severe or fatal injury,
respiratory illness or cancer. The use
and disposal of asbestos-containing
products have been strictly regulated by
OSHA and the Environmental Protection Agency. If you have any reason to
believe that you might be cutting asbestos, immediately contact your employer
or a local OSHA representative.
Operating Instructions
Warning!
Do not operate your power tool using
the starting throttle lock, as you do not
have control of the engine speed.
In the event of an emergency, switch off
the engine immediately – move the slide
control / stop switch to 0 or STOP.
Warning!
Always stop the engine before putting a
chain saw down.
Warning!
The saw chain continues to move for a
short period after the throttle trigger is
released (flywheel effect).
Accelerating the engine while the saw
chain is blocked increases the load and
will cause the clutch to slip continuously.
This may occur if the throttle is
depressed for more than a few seconds
when the chain is pinched in the cut or
the chain brake is engaged. It can result
in overheating and damage to important
components (e.g. clutch, polymer
housing components) – which can then
increase the risk of injury, e.g., from the
saw chain moving while the engine is
idling.
Warning!
Your chain saw is equipped with a chain
catcher. It is designed to reduce the risk
of personal injury in the event of a
thrown or broken chain. From time to
time, the catcher may be damaged or
removed. To reduce the risk of personal
injury, do not operate a chain saw with a
damaged or missing chain catcher.
Warning!
Inspect antivibration elements periodically. Replace damaged, broken or
excessively worn antivibration elements
immediately, since they may result in
loss of control of the saw. A "sponginess" in the feel of the saw, increased
vibration or increased "bottoming" during normal operation may indicate
damage, breakage or excessive wear.
Antivibration elements should always
be replaced in sets. If you have any
questions as to whether the antivibration elements should be replaced,
consult your STIHL servicing dealer.
Warning!
Your saw is not designed for prying or
shoveling away limbs, roots or other
objects. Such use could damage the
cutting attachment or AV system.
English
Warning!
When sawing, make sure that the saw
chain does not touch any foreign materials such as rocks, fences, nails and the
like. Such objects may be flung off,
damage the saw chain or cause the saw
to kickback.
Warning!
The muffler and other parts of the
engine (e.g. fins of the cylinder, spark
plug) become hot during operation and
remain hot for a while after stopping the
engine. To reduce risk of burns do not
touch the muffler and other parts while
they are hot.
Warning!
To reduce the risk of fire and burn injury,
keep the area around the muffler clean.
Remove excess lubricant and all debris
such as pine needles, branches or
leaves. Let the engine cool down sitting
on concrete, metal, bare ground or solid
wood (e.g. the trunk of a felled tree)
away from any combustible substances.
Warning!
Never modify your muffler. A modified or
damaged muffler could cause an
increase in heat radiation or sparks,
thereby increasing the risk of fire and
burn injury. You may also permanently
damage the engine. Have your muffler
serviced and repaired by your STIHL
servicing dealer only.
MS 271, MS 291, MS 291 C
11
English
001BA093 LÄ
001BA035 KN
Catalytic Converter
Warning!
Some STIHL power tools
are equipped with a catalytic converter, which is
designed to reduce the
exhaust emissions of the
engine by a chemical
process in the muffler. Due to this process, the muffler does not cool down as
rapidly as conventional mufflers when
the engine returns to idle or is shut off.
To reduce the risk of fire and burn injuries, the following specific safety
precautions must be observed.
Warning!
Since a muffler with a catalytic converter
cools down less rapidly than conventional mufflers, always set your power
tool down in the upright position and
never locate it where the muffler is near
dry brush, grass, wood chips or other
combustible materials while it is still hot.
Warning!
An improperly mounted or damaged
shroud or a damaged / deformed muffler
shell may interfere with the cooling process of the catalytic converter. To reduce
the risk of fire or burn injury, do not continue work with a damaged or
improperly mounted cylinder shroud or
a damaged / deformed muffler shell.
Your catalytic converter is furnished with
screens designed to reduce the risk of
fire from the emission of hot particles.
Due to the heat from the catalytic
reaction, these screens will normally
stay clean and need no service or
maintenance. If you experience loss of
performance and you suspect a clogged
screen, have your muffler maintained by
a STIHL servicing dealer.
Reactive Forces including Kickback
Warning!
Reactive forces may occur any time the
chain is rotating. Reactive forces can
cause serious personal injury.
The powerful force used to cut wood can
be reversed and work against the
operator. If the rotating chain is suddenly
stopped by contact with any solid object
such as a log or branch or is pinched, the
reactive forces may occur instantly.
These reactive forces may result in loss
of control, which, in turn, may cause
serious or fatal injury. An understanding
of the causes of these reactive forces
may help you avoid the element of
surprise and loss of control. Sudden
surprise contributes to accidents.
The most common reactive forces are:
– kickback,
– pushback,
– pull-in.
Kickback:
Kickback may occur
when the moving saw
chain near the upper
quadrant of the bar nose
contacts a solid object or
is pinched.
The reaction of the cutting force of the
chain causes a rotational force on the
chain saw in the direction opposite to the
chain movement. This may fling the bar
up and back in a lightning fast reaction in
an uncontrolled arc mainly in the plane
of the bar. Under some cutting
circumstances the bar moves towards
the operator, who may suffer severe or
fatal injury.
Kickback may occur, for example, when
the chain near the upper quadrant of the
bar nose contacts the wood or is
pinched during limbing or when it is
incorrectly used to begin a plunge or
boring cut.
12
MS 271, MS 291, MS 291 C
English
The greater the force of the kickback
reaction, the more difficult it becomes for
the operator to control the saw. Many
factors influence the occurrence and
force of the kickback reaction. These
include chain speed, the speed at which
the bar and chain contact the object, the
angle of contact, the condition of the
chain and other factors.
The type of bar and saw chain you use
is an important factor in the occurrence
and force of the kickback reaction. Some
STIHL bar and chain types are designed
to reduce kickback forces. STIHL
recommends the use of reduced
kickback bars and low kickback chains.
ANSI B 175.1-2000 chain saw
kickback standard
§ 5.11 of ANSI standard B 175.1-2000,
sets certain performance and design
criteria related to chain saw kickback.
To comply with § 5.11 of ANSI
B 175.1-2000:
a) Saws with a displacement of less
than 3.8 cubic inches (62 cm³)
– must, in their original condition,
meet a 45° computer derived
kickback angle when equipped with
certain cutting attachments,
– and must be equipped with at least
two devices to reduce the risk of
kickback injury, such as a chain
brake, low kickback chain, reduced
kickback bar, etc.
b) Saws with a displacement of
3.8 cubic inches (62 cm³) and
above
– must be equipped with at least one
device designed to reduce the risk
of kickback injury, such as a chain
brake, low kickback chain, reduced
kickback bar, etc.
The computer derived angles for saws
below 3.8 cubic inches (62 cm³)
displacement are measured by applying
a computer program to test results from
a kickback test machine.
Warning!
The computer derived angles of § 5.11
of ANSI B 175.1-2000 may bear no relationship to actual kickback bar rotation
angles that may occur in real life cutting
situations.
In addition, features designed to reduce
kickback injuries may lose some of their
effectiveness when they are no longer in
their original condition, especially if they
have been improperly maintained.
Compliance with § 5.11 of ANSI
B 175.1-2000 does not automatically
mean that in a real life kickback the bar
and chain will rotate at most 45°.
Warning!
In order for powerheads below 3.8 cubic
inches (62 cm³) displacement to comply
with the computed kickback angle
requirements of § 5.11 of ANSI
B 175.1-2000 use only the following cutting attachments:
– bar and chain combinations listed
as complying in the "Specifications"
section of the instruction manual or
– other replacement bar and chain
combinations marked in
accordance with the standard for
use on the powerhead or
– replacement chain designated "low
kickback saw chain."
See the section on "Low kickback saw
chain and reduced kickback bars."
Devices for Reducing the Risk of
Kickback Injury
STIHL recommends the use of the
STIHL Quickstop chain brake on your
powerhead with green labeled reduced
kickback bars and low kickback chains.
Warning!
To reduce the risk of injury, never use a
saw if the chain brake does not function
properly. Take the saw to your local
STIHL servicing dealer. Do not use the
saw until the problem has been rectified.
STIHL Quickstop Chain Brake
STIHL has developed a chain stopping
system designed to reduce the risk of
injury in certain kickback situations. It is
called a Quickstop chain brake.
MS 271, MS 291, MS 291 C
13
English
001BA174 KN
All STIHL chain saws are equipped with
a Quickstop chain brake which can be
activated by inertia. If the forces of an
occurring kickback are sufficiently high,
the hand guard is accelerated towards
the bar nose even without hand contact.
See the chapter entitled "Chain Brake"
of your instruction manual.
Warning!
Never operate your chain saw without a
front hand guard. In a kickback situation
this guard helps protect your left hand
and other parts of your body. In addition,
removal of the hand guard on a saw
equipped with a Quickstop chain brake
will deactivate the chain brake.
Warning!
No Quickstop or other chain brake
device prevents kickback. These
devices are designed to reduce the risk
of kickback injury, if activated, in certain
kickback situations. In order for the
Quickstop to reduce the risk of kickback
injury, it must be properly maintained
and in good working order. See the
chapter of your instruction manual entitled "Chain Brake" and the section
"Maintenance, Repair and Storing" at
the end of these Safety Precautions. In
addition, there must be enough distance
between the bar and the operator to
ensure that the Quickstop has sufficient
time to activate and stop the chain
before potential contact with the
operator.
Warning!
An improperly maintained chain brake
may increase the time needed to stop
the chain after activation, or may not
activate at all.
Warning!
Never run the chain saw above idle
speed for more than 3 seconds when
the chain brake is engaged or when the
chain is pinched or otherwise caught in
the cut. Clutch slippage can cause
excessive heat, leading to severe damage of the motor housing, clutch and
oiler component and may interfere with
the operation of the chain brake. If
clutch slippage in excess of 3 seconds
has occurred, allow the motor housing
to cool before proceeding and check the
operation of your chain brake as
described in the chapter entitled "Chain
Brake" of your instruction manual. Also
make sure that the chain is not turning
at idle speed (see above at "Important
Adjustments").
Low Kickback Saw Chain and
Reduced Kickback Bars
STIHL offers a variety of bars and
chains. STIHL reduced kickback bars
and low kickback chains are designed to
reduce the risk of kickback injury. Other
chains are designed to obtain higher
cutting efficiency or sharpening ease but
may result in higher kickback tendency.
STIHL has developed a color code
system to help you identify the STIHL
reduced kickback bars and low kickback
chains. Cutting attachments with green
warning decals or green labels on the
packaging are designed to reduce the
risk of kickback injury. The matching of
green decaled powerheads under
3.8 cubic inches (62 cm³) displacement
with green labeled bars and green
labeled chains gives compliance with
the computed kickback angle
requirements of ANSI B 175.1-2000
14
MS 271, MS 291, MS 291 C
when the products are in their original
condition. Products with yellow decals or
labels are for users with extraordinary
cutting needs and experience and
specialized training for dealing with
kickback.
STIHL recommends the use of its
green labeled reduced kickback bars,
green labeled low kickback chains
and a STIHL Quickstop chain brake
for both experienced and
inexperienced chain saw users.
Please ask your STIHL dealer to
properly match your powerhead with the
appropriate bar / chain combination to
reduce the risk of kickback injury. Green
labeled bars and chains are
recommended for all powerheads.
Warning!
Use of other, non-listed bar / chain combinations may increase kickback forces
and the risk of kickback injury. New bar
/ chain combinations may be developed
after publication of this literature, which
will, in combination with certain powerheads, comply with § 5.11 of ANSI
B 175.1-2000. Check with your STIHL
dealer for such combinations.
Warning!
Reduced kickback bars and low kickback chains do not prevent kickback,
but they are designed to reduce the risk
of kickback injury. They are available
from your STIHL dealer.
Warning!
Even if your saw is equipped with a
Quickstop, a reduced kickback bar and
/ or low kickback chain, this does not
eliminate the risk of injury by kickback.
Therefore, always observe all safety
precautions to avoid kickback
situations.
Low Kickback Chain
Some types of saw chain have specially
designed components to reduce the
force of nose contact kickback. STIHL
has developed low kickback chain for
your powerhead.
"Low kickback saw chain" is a chain
which has met the kickback
performance requirements of § 5.11.2.4
of ANSI B 175.1-2000 (GasolinePowered Chain Saws–Safety
Requirements) when tested in its
original condition on a selected
representative sample of chain saws
below 3.8 cubic inches (62 cm³)
displacement specified in ANSI
B 175.1-2000.
Warning!
There are potential powerhead and bar
combinations with which low kickback
saw chains can be used which have not
been specifically certified to comply with
the 45° computer derived kickback
angle of § 5.11 of ANSI B 175.1-2000.
Some low kickback chains have not
been tested with all powerhead and bar
combinations.
English
Warning!
A dull or improperly sharpened chain
may reduce or negate the effects of the
design features intended to reduce kickback energy. Improper lowering or
sharpening of the depth gauges or
shaping of the cutters may increase the
chance and the potential energy of a
kickback. Always cut with a properly
sharpened chain.
Reduced Kickback Bars
STIHL green labeled reduced kickback
bars are designed to reduce the risk of
kickback injury when used with STIHL
green labeled low kickback chains.
Warning!
When used with other, more aggressive
chains, these bars may be less effective
in reducing kickback.
Warning!
For a properly balanced saw and in
order to comply with § 5.12.1 of ANSI
B 175.1-2000, use only bar lengths
listed in the specifications chapter of the
instruction manual for your chain saw
powerhead.
MS 271, MS 291, MS 291 C
15
English
001BA037 KN
A
001BA038 KN
B
Bow Guides
Warning!
Do not mount a bow guide on any
STIHL chain saw. Any chain saw
equipped with a bow guide is potentially
very dangerous. The risk of kickback is
increased with a bow guide because of
the increased kickback contact area.
Low kickback chain will not significantly
reduce the risk of kickback injury when
used on a bow guide.
To avoid Kickback
The best protection from personal injury
that may result from kickback is to avoid
kickback situations:
1. Hold the chain saw firmly with both
hands and maintain a secure grip.
Don’t let go.
2. Be aware of the location of the guide
bar nose at all times.
3. Never let the nose of the guide bar
contact any object. Do not cut limbs
with the nose of the guide bar. Be
especially careful near wire fences
and when cutting small, tough
limbs, small size brush and saplings
which may easily catch the chain.
4. Don't overreach.
5. Don't cut above shoulder height.
6. Begin cutting and continue at full
throttle.
7. Cut only one log at a time.
8. Use extreme caution when
reentering a previous cut.
9. Do not attempt to plunge cut if you
are not experienced with these
cutting techniques.
10. Be alert for shifting of the log or
other forces that may cause the cut
to close and pinch the chain.
11. Maintain saw chain properly. Cut
with a correctly sharpened, properly
tensioned chain at all times.
12. Stand to the side of the cutting path
of the chain saw.
A = Pull-in
Pull-in occurs when the chain on the
bottom of the bar is suddenly stopped
when it is pinched, caught or encounters
a foreign object in the wood. The
reaction of the chain pulls the saw
forward and may cause the operator to
lose control.
Pull-in frequently occurs when the
bumper spike of the saw is not held
securely against the tree or limb and
when the chain is not rotating at full
speed before it contacts the wood.
Warning!
Use extreme caution when cutting small
size brush and saplings which may easily catch the chain, be whipped towards
you or pull you off balance.
To avoid Pull-in
1. Always start a cut with the chain
rotating at full speed and the
bumper spike in contact with the
wood.
2. The risk of pull-in may also be
reduced by using wedges to open
the kerf or cut.
B = Pushback
Pushback occurs when the chain on the
top of the bar is suddenly stopped when
it is pinched, caught or encounters a
foreign object in the wood. The reaction
of the chain may drive the saw rapidly
straight back toward the operator and
may cause loss of saw control.
Pushback frequently occurs when the
top of the bar is used for cutting.
To avoid Pushback
1. Be alert to forces or situations that
may cause material to pinch the top
of the chain.
2. Do not cut more than one log at a
time.
3. Do not twist the saw when
withdrawing the bar from a plunge
cut or underbuck cut because the
chain can pinch.
16
MS 271, MS 291, MS 291 C
English
001BA088 LÄ
2
/
1
2
1 1
/
1
2
B
001BA040 KN
A
45°
45°
B
Cutting Techniques
Felling
Felling is cutting down a tree.
Before felling a tree, consider carefully
all conditions which may affect the
direction of fall.
Warning!
There are a number of factors that may
affect and change the intended direction
of fall, e.g. wind direction and speed,
lean of tree, surrounding trees and
obstacles, sloping ground, one-sided
limb structure, wood structure, decay,
snow load, etc. To reduce the risk of
severe or fatal injury to yourself or others, look for these conditions prior to
beginning the cut, and be alert for a
change in direction while the tree is
falling.
Warning!
Always observe the general condition of
the tree. Inexperienced users should
never attempt to cut trees that are
decayed or rotted inside or that are
leaning or otherwise under tension.
There is an increased risk that such
trees could snap or split while being cut
and cause serious or fatal injury to the
operator or bystanders. Also look for
broken or dead branches which could
vibrate loose and fall on the operator.
When felling on a slope, the operator
should stand on the uphill side if
possible.
Felling Instructions
When felling, maintain a distance of at
least 2 1/2 tree lengths from the nearest
person.
When felling in the vicinity of roads,
railways and power lines, etc., take extra
precautions. Inform the police, utility
company or railway authority before
beginning to cut.
Warning!
The noise of your engine may drown
any warning call.
Escape Path
First clear the tree base and work area
from interfering limbs and brush and
clean its lower portion with an ax.
Then, establish two paths of escape (B)
and remove all obstacles. These paths
should be generally opposite to the
planned direction of the fall of the tree
(A) and about at a 45° angle. Place all
tools and equipment a safe distance
away from the tree, but not on the
escape paths.
MS 271, MS 291, MS 291 C
17
English
001BA146 KN
001BA153 KN
001BA143 KN
C
C
Buttress Roots
If the tree has large buttress roots, cut
into the largest buttress vertically first
(horizontally next) and remove the
resulting piece.
Gunning Sight
When making the felling notch, use the
gunning sight on the shroud and housing
to check the desired direction of fall:
Position the saw so that the gunning
sight points exactly in the direction you
want the tree to fall.
Conventional Cut
Felling notch (C) – determines the
direction of the fall
For a conventional cut:
N Properly place felling notch
perpendicular to the line of fall,
close to the ground.
N Cut down at approx. 45° angle to a
depth of about 1/5 to 1/4 of the trunk
diameter.
N Make second cut horizontal.
N Remove resulting 45° piece.
Open-face Technique
Felling notch (C) – determines the
direction of the fall
For an open-face cut:
N Properly place felling notch
perpendicular to the line of fall,
close to the ground.
N Cut down at approx. 50° angle to a
depth of approx.1/5 to 1/4 of the
trunk diameter.
N Make second cut from below at
approx. 40 degree angle.
N Remove resulting 90° piece.
18
MS 271, MS 291, MS 291 C
English
001BA150 KN
001BA144 KN
D
D
001BA145 KN
E
E
Making Sapwood Cuts
N For medium sized or larger trees
make cuts at both sides of the trunk,
at same height as subsequent
felling cut.
N Cut to no more than width of guide
bar.
This is especially important in softwood
in summer – it helps prevent sapwood
splintering when the tree falls.
D =Felling Cut
Conventional and open-face technique:
N Begin 1 to 2 inches (2,5 to 5 cm)
higher than center of felling notch.
N Cut horizontally towards the felling
notch.
N Leave approx.1/10 of diameter
uncut. This is the hinge.
N Do not cut through the hinge – you
could lose control of the direction of
the fall.
Drive wedges into the felling cut where
necessary to control the fall.
E = Hinge
N Helps control the falling tree.
N Do not cut through the hinge – you
could lose control of the direction of
the fall.
MS 271, MS 291, MS 291 C
Warning!
If the tip of the bar contacts a wedge, it
may cause kickback. Wedges should be
of wood or plastic – never steel, which
can damage the chain.
19
English
001BA147 KN
001BA148 KN
1
4
2
Felling Cut for Small Diameter Trees:
Simple Fan Cut
Engage the bumper spikes of the chain
saw directly behind the location of the
intended hinge and pivot the saw around
this point only as far as the hinge. The
bumper spike rolls against the trunk.
Felling Cut for Large Diameter Trees
Warning!
Felling a tree that has a diameter
greater than the length of the guide bar
requires use of either the sectioning felling cut or plunge-cut method. These
methods are extremely dangerous
because they involve the use of the
nose of the guide bar and can result in
kickback. Only properly trained professionals should attempt these
techniques.
Sectioning Method
For the sectioning method make the first
part of the felling cut with the guide bar
fanning in toward the hinge. Then, using
the bumper spike as a pivot, reposition
the saw for the next cut.
Avoid repositioning the saw more than
necessary. When repositioning for the
next cut, keep the guide bar fully
engaged in the kerf to keep the felling
cut straight. If the saw begins to pinch,
insert a wedge to open the cut. On the
last cut, do not cut the hinge.
Plunge-cut Method
Timber having a diameter more than
twice the length of the guide bar requires
the use of the plunge-cut method before
making the felling cut.
First, cut a large, wide felling notch.
Make a plunge cut in the center of the
notch.
20
MS 271, MS 291, MS 291 C
English
001BA033 KN
The plunge cut is made with the guide
bar nose. Begin the plunge cut by
applying the lower portion of the guide
bar nose to the tree at an angle. Cut until
the depth of the kerf is about the same
as the width of the guide bar. Next, align
the saw in the direction in which the
recess is to be cut.
With the saw at full throttle, insert the
guide bar in the trunk.
Enlarge the plunge cut as shown in the
illustration.
Warning!
There is an extreme danger of kickback at this point. Extra caution must
be taken to maintain control of the
saw. To make the felling cut, follow
the sectioning method described
previously.
If you are inexperienced with a chain
saw, plunge-cutting should not be
attempted. Seek the help of a
professional.
Warning!
In order to reduce the risk of personal
injury, never stand directly behind the
tree when it is about to fall, since part of
the trunk may split and come back
towards the operator (barber-chairing),
or the tree may jump backwards off the
stump. Always keep to the side of the
falling tree. When the tree starts to fall,
withdraw the bar, shut off the engine
and walk away on the preplanned
escape path. Watch out for falling limbs.
Warning!
Be extremely careful with partially fallen
trees which are poorly supported. When
the tree hangs or for some other reason
does not fall completely, set the saw
aside and pull the tree down with a
cable winch, block and tackle or tractor.
If you try to cut it down with your saw,
you may be injured.
Limbing
Limbing is removing the branches from a
fallen tree.
Warning!
There is an extreme danger of kickback
during the limbing operation. Do not
work with the nose of the bar. Be
extremely cautious and avoid contacting the log or other limbs with the nose
of the guide bar.
Do not stand on a log while limbing it –
you may slip or the log may roll.
Start limbing by leaving the lower limbs
to support the log off the ground. When
underbucking freely hanging limbs, a
pinch may result or the limb may fall,
causing loss of control. If a pinch occurs,
stop the engine and remove the saw by
lifting the limb.
Warning!
Be extremely cautious when cutting
limbs or logs under tension (spring
poles). The limbs or logs could spring
back toward the operator and cause
loss of control of the saw and severe or
fatal injury to the operator.
Bucking
Bucking is cutting a log into sections.
MS 271, MS 291, MS 291 C
21
English
001BA051 LÄ
1
001BA151 KN
2
1
001BA152 KN
2
Warning!
When bucking, do not stand on the log.
Make sure the log will not roll downhill. If
on a slope, stand on the uphill side of
the log. Watch out for rolling logs.
Cut only one log at a time.
Shattered wood should be cut very
carefully. Sharp slivers of wood may be
caught and flung in the direction of the
operator of the saw.
When cutting small logs, place log
through "V"-shaped supports on top of a
sawhorse. Never permit another person
to hold the log. Never hold the log with
your leg or foot.
Logs under strain:
Risk of pinching! Always start relieving
cut (1) at compression side.Then make
bucking cut (2) at tension side. If the saw
pinches, stop the engine and remove it
from the log.
Only properly trained professionals
should work in an area where the logs,
limbs and roots are tangled. Working in
"blow down" areas is extremely
hazardous. Drag the logs into a clear
area before cutting. Pull out exposed
and cleared logs first.
MAINTENANCE, REPAIR AND
STORING
Maintenance, replacement, or repair
of the emission control devices and
systems may be performed by any
nonroad engine repair establishment
or individual. However, if you make a
warranty claim for a component
which has not been serviced or
maintained properly or if
nonapproved replacement parts were
used, STIHL may deny coverage.
Warning!
Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.
Strictly follow the maintenance and
repair instructions in the appropriate
section of your instruction manual.
Please refer to the maintenance chart in
this manual.
Warning!
Always stop the engine and make sure
that the cutting tool is stopped before
doing any maintenance or repair work or
cleaning the power tool.
Warning!
Do not attempt any maintenance or
repair work not described in your
instruction manual. Have such work performed by your STIHL servicing dealer
only. For example, if improper tools are
used to remove the flywheel or if an
improper tool is used to hold the flywheel in order to remove the clutch,
structural damage to the flywheel could
occur and could subsequently cause the
flywheel to burst.
Wear gloves when handling or
performing maintenance on saw chains.
22
MS 271, MS 291, MS 291 C
English
Warning!
Use the specified spark plug and make
sure it and the ignition lead are always
clean and in good condition. Always
press spark plug boot snugly onto spark
plug terminal of the proper size. (Note: If
terminal has detachable SAE adapter
nut, it must be securely attached.) A
loose connection between spark plug
terminal and the ignition wire connector
in the boot may create arcing that could
ignite combustible fumes and cause a
fire.
Warning!
Never test the ignition system with the
spark plug boot removed from the spark
plug or with a removed spark plug, since
uncontained sparking may cause a fire.
Warning!
Do not operate your chain saw if the
muffler is damaged, missing or modified. An improperly maintained muffler
will increase the risk of fire and hearing
loss.
If your muffler was equipped with a
spark-arresting screen to reduce the risk
of fire, never operate your saw if the
screen is missing or damaged.
Remember that the risk of forest fires is
greater in hot or dry weather.
Keep the chain, bar and sprocket clean;
replace worn sprockets or chains. Keep
the chain sharp. You can spot a dull
chain when easy-to-cut wood becomes
hard to cut and burn marks appear on
the wood. Keep the chain at proper
tension.
Tighten all nuts, bolts and screws except
the carburetor adjustment screws after
each use.
Warning!
In order for the chain brake on your
STIHL chain saw to properly perform its
function of reducing the risk of kickback
and other injuries, it must be properly
maintained. Like an automobile brake, a
chain saw chain brake incurs wear each
time it is engaged.
The amount of wear will vary depending
upon usage, conditions under which the
saw is used and other factors. Excessive
wear will reduce the effectiveness of the
chain brake and can render it
inoperable.
For the proper and effective operation of
the chain brake, the brake band and
clutch drum must be kept free of dirt,
grease and other foreign matter which
may reduce friction of the band on the
drum.
For these reasons, each STIHL chain
saw should be returned to trained
personnel such as your STIHL servicing
dealer for periodic inspection and
servicing of the brake system according
to the following schedule:
Heavy usage – every three months,
Moderate usage – twice a year,
Occasional usage – annually.
The chain saw should also be returned
immediately for maintenance whenever
the brake system cannot be thoroughly
cleaned or there is a change in its
operating characteristics.
For any maintenance of the emission
control system please refer to the
maintenance chart and to the limited
warranty statement near the end of the
instruction manual.
Do not clean your machine with a
pressure washer. The solid jet of water
may damage parts of the machine.
Store chain saw in a dry place and away
from children. Before storing for longer
than a few days, always empty the fuel
tank (see chapter "Storing the Machine"
in the instruction manual).
MS 271, MS 291, MS 291 C
23
English
001BA191 KN
1
2
3
a
t = a : 2
143BA034 KN
1
2
001BA185 KN
001BA186 KN
143BA003 KN
Cutting Attachment
STIHL is the only manufacturer in the
industry to produce its own chain saws,
guide bars, saw chains and chain
sprockets.
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.
– The pitch (t) of the saw chain (1),
chain sprocket and the nose
sprocket of the Rollomatic 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 cutting attachment may be damaged
beyond repair after a short period of
operation.
Mounting the Bar and
Chain (side chain
tensioner)
Removing the chain sprocket cover
N Unscrew the nuts and take off the
chain sprocket cover.
N Turn the screw (1)
counterclockwise until the tensioner
slide (2) butts against the left end of
the housing slot.
Disengaging the chain brake.
N Pull the hand guarad towards the
front handle until there is an audible
click – the chain brake is
disengaged.
Fitting the chain
Wear work gloves to protect your
hands from the sharp cutters.
N Fit the chain – start at the bar nose.
24
MS 271, MS 291, MS 291 C
English
3
1
1
2
4
001BA187 KN
2
1
133BA026 KN
3
1
172BA007 KN
2
172BA008 KN
1
5
4
3
172BA009 KN
N Fit the guide bar over the studs (1) –
the cutting edges on the top of the
bar must point to the right.
N Engage the peg of the tensioner
slide in the locating hole (2) –- place
the chain over sprocket (3) at the
same time.
N Turn the tensioning
screw (4)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.
N Refit the sprocket cover and screw
on the nuts only fingertight.
N Go to chapter on "Tensioning the
Saw Chain"
Mounting the Bar and
Chain (quick chain
tensioner)
Remove the chain sprocket cover.
N Pull out the hinged clip (1) so that it
snaps into position.
N Turn the wingnut (2)
counterclockwise until it hangs
loose
N in the sprocket cover (3).
N Removing the sprocket cover
Fitting the tensioning gear
N Remove the tensioning gear (1) and
turn it over.
N Unscrew the nut (2).
N Position the tensioning gear (1)
against the guide bar (3) so that the
stud (4) projects through the upper
hole and the short guide peg (5)
locates in the lower hole.
MS 271, MS 291, MS 291 C
25
English
2
172BA010 KN
001BA186 KN
1
172BA011 KN
3
2
172BA012 KN
172BA013 KN
3
172BA014 KN
Fitting the chain
N Screw the nut (2) on to the stud as
far as stop by hand.
Releasing the chain brake
N Pull the hand guarad towards the
front handle until there is an audible
click – the chain brake is
disengaged.
Wear work gloves to protect your
hands from the sharp cutters.
N Fit the chain – start at the bar nose.
Pay attention to the position of the
tensioning gear and the cutting
edges.
N Turn the tensioning gear (1)
clockwise as far as stop.
N Turn the guide bar so that the
tensioning gear is facing you.
N Fit the chain over the sprocket (2).
N Fit guide bar in position – the collar
screw (3) engages the hole in the
tensioning gear. The heads of the
two short collar screws locate in the
guide bar slot.
N Make sure the drive link tangs
engage the bar groove (see arrow)
and then rotate the tensioning gear
counterclockwise as far as stop.
26
N Fit the chain sprocket cover so that
the wingnut locates on the collar
screw (3).
MS 271, MS 291, MS 291 C
English
5
4
172BA015 KN
1
133BA024 KN
1
2
001BA112 KN
When fitting the chain sprocket cover,
check that the teeth of the tensioning
gear and adjusting wheel mesh properly.
N If necessary, turn the adjusting
wheel (4) slightly until the sprocket
cover can be pushed flush against
the engine housing.
N Pull out the hinged clip (5) so that it
snaps into position.
N Engage wingnut and tighten it down
moderately.
N Go to chapter on "Tensioning the
Saw Chain"
Tensioning the Saw Chain
(side chain tensioner)
Retensioning during cutting work:
N Shut off the engine.
N Loosen the nuts.
N Hold the bar nose up.
N Use a screwdriver to turn the
tensioning screw (1) clockwise until
the chain fits snugly against the
underside of the bar.
N While still holding the bar nose up,
tighten down the nuts firmly.
N Go to "Checking Chain Tension".
A new chain has to be retensioned more
often than one that has been in use for
some time.
N Check chain tension frequently –
see chapter on "Operating
Instructions".
Tensioning the Saw Chain
(quick chain tensioner)
Retensioning during cutting work:
N Shut off the engine.
N Pull out the hinged clip and loosen
the wingnut.
N Turn the adjusting wheel (1)
clockwise as far as stop.
N Tighten down the wingnut (2) firmly
by hand.
N Fold down the hinged clip.
N Go to "Tensioning the Saw Chain"
A new chain has to be retensioned more
often than one that has been in use for
some time.
N Check chain tension frequently –
see chapter on "Operating
Instructions".
MS 271, MS 291, MS 291 C
27
English
143BA007 KN
Checking Chain Tension
N Shut off the engine.
N Wear work gloves to protect your
hands.
N The chain must fit snugly against
the underside of the bar and it must
still be possible to pull the chain
along the bar by hand.
N If necessary, retension the chain.
A new chain has to be retensioned more
often than one that has been in use for
some time.
N Check chain tension frequently –
see chapter on "Operating
Instructions".
Fuel
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of highquality gasoline and quality two-stroke
air cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2). If
the octane rating of the mid-grade
gasoline in your area is lower, use
premium unleaded fuel.
Fuel with a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
high-quality unleaded gasoline!
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
with a manually adjustable carburetor
and should not be used in such engines.
Engines equipped with M-Tronic can be
run on gasoline with an ethanol content
of up to 25% (E25).
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke
engine oils that are designed for use
only in air cooled two-cycle engines.
We recommend STIHL HP Ultra 2-Cycle
Engine Oil since it is specially
formulated for use in STIHL engines.
Do not use BIA or TCW rated (twostroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chain saws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the canister from
your vehicle and place the canister on
the ground before filling. Do not fill fuel
canisters that are sitting in or on a
vehicle.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The machine‘s fuel tank and the canister
in which fuel mix is stored should be
cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days
work, not to exceed 3 months of storage.
Store in approved fuel-canisters only.
When mixing, pour oil into the canister
first, and then add gasoline. Close the
canister and shake it vigorously by hand
to ensure proper mixing of the oil with
the fuel.
28
MS 271, MS 291, MS 291 C
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