Stihl MS 291 C-Q User manual

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STIHL MS 291 C-Q Instruction Manual
Manual de instrucciones
Warning!
To reduce the risk of kickback injury use
STIHL reduced kickback bar and STIHL
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
RMC3 (0,325 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 - 127

Original Instruction ManualPrinted on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2011 0458-576-8621-A. M0-38.B11.DDS. 0000003131_002_GB
MS 291 C-Q
English
1
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Contents
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.
Quickstop Plus Chain Brake
System 2
Guide to Using this Manual 3
Safety Precautions and Working
Techniques 4
Cutting Attachment 25
Mounting the Bar and Chain (quick
chain tensioner) 25
Tensioning the Saw Chain (quick
chain tensioner) 27
Checking Chain Tension 27
Fuel 28
Fueling 29
Chain Lubricant 30
Filling Chain Oil Tank 31
Checking Chain Lubrication 31
Chain Brake 32
Winter Operation 33
Starting / Stopping the Engine 34
Operating Instructions 38
Taking Care of the Guide Bar 39
Shroud 39
Air Filter System 40
Cleaning the Air Filter 40
Engine Management 41
Adjusting the Carburetor 41
Spark Arresting Screen in Muffler 42
Spark Plug 42
Replacing the Starter Rope and
Rewind Spring 44
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 56
Maintenance and Repairs 57
STIHL Incorporated Federal
Emission Control Warranty
Statement 57
Trademarks 59
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.

MS 291 C-Q
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This STIHL chain saw is equipped with a
chain brake system that can be
activated in three different ways. As
before, the chain brake can be activated
by the inertia of the front hand guard in
certain kickback situations or manually
by pushing the front hand guard toward
the bar nose. In both of these cases the
brake, once activated, is designed to
bring the chain to a standstill within
fractions of a second. In addition, there
is a secondary system (STIHL
Quickstop Plus) that is designed to stop
chain rotation within a second of the
operator fully releasing the rear handle.
The locked chain is not released again
until you press down the throttle trigger
lockout to operate the throttle.
The chain brake can be activated in
three ways:
1By inertia in certain kickback
situations
2Manually via the front hand guard
3Manually by fully releasing the rear
handle, including the throttle trigger
and throttle trigger lockout.
The activating mechanism for the STIHL
Quickstop Plus chain brake system is
integrated in the throttle trigger lockout
(rear handle). One of the big advantages
of this system is that the saw chain is
automatically locked in position when
carrying the running saw by the front
handle (with the rear handle fully
released).
Quickstop Plus Chain
Brake System
2
1
150BA000 KN
To reduce the risk of personal
injury or property damage during
cutting, observe the
characteristics that make this saw
different from saws not equipped
with a STIHL Quickstop Plus
chain brake system. Before
operating the chain saw for the
first time, make sure you are
familiar with how the rear-handle
activation works. Pay special
attention to the chapter "Chain
Brake."

MS 291 C-Q
English
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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.
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:
NA 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:
NLoosen the screw (1).
NLever (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:
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.
Guide to Using this Manual
Fuel tank; fuel mixture of
gasoline and engine oil
Chain oil tank; chain oil
Engaging and disengag-
ing the STIHL Quickstop
chain brake
STIHL Quickstop Plus
chain brake system
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
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.

MS 291 C-Q
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Have your STIHL dealer show you how
to operate your power tool. All safety
precautions that are generally observed
when working with an axe 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.
Use your chain saw only for cutting
wooden objects.
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 power tool 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.
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.
Warning!
Do not lend or rent your power tool with-
out the instruction manual. Be sure that
anyone using it understands the infor-
mation contained in this manual.
Warning!
The use of this machine may be hazard-
ous.The saw chain has many sharp
cutters. If the cutters contact your flesh,
they will cut you, even if the chain is not
moving.
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 bystand-
ers 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 unauthor-
ized persons do not use it.
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 dis-
ease (Raynaud's phenomenon) or
carpal tunnel syndrome.

MS 291 C-Q
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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 white-
finger 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 power-
heads, 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.
Proper Clothing
Warning!
The ignition system of the STIHL unit
produces an electromagnetic field of a
very low intensity. This field may inter-
fere with some pacemakers. To reduce
the risk of serious or fatal injury, persons
with a pacemaker should consult their
physician and the pacemaker manufac-
turer before operating this tool.
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 jack-
ets, 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.

MS 291 C-Q
English
6
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
"Main Parts."
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
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 oil-
gasoline mixture for fuel (see the
chapter on "Fuel" of your instruction
manual).
Warning!
To reduce the risk of
injury to your eyes never
operate your power tool
unless wearing goggles
or properly fitted protec-
tive glasses with
adequate top and side protection com-
plying 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.
Wear an approved safety hard hat to
reduce the risk of injury to your head
when there is a danger of head injuries.
Chain saw noise may damage your
hearing. Wear sound barriers (ear plugs
or ear mufflers) to protect your hearing.
Continual and regular users should
have their hearing checked regularly.
Always wear gloves
when handling the
machine and the cutting
tool. Heavy-duty, nonslip
gloves improve your grip
and help to protect your
hands.
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 unauthor-
ized attachments are useable with
STIHL power tools, their use may, in
fact, be extremely dangerous.
Warning!
To reduce the risk of injury from saw
chain contact, never carry or transport
your power tool with the saw chain mov-
ing. 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 spill-
age and damage to the unit.
001BA115 KN

MS 291 C-Q
English
7
Fueling Instructions
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.
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.
Different models may be equipped with
different fuel caps.
Toolless cap with grip
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
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).
Misaligned, damaged or broken cap
NIf 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.
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.
Warning!
Fuel your power tool in well-ventilated
areas, outdoors. Always shut off the
engine and allow it to cool before refu-
eling. Gasoline vapor pressure may
build up inside the fuel tank depending
on the fuel used, the weather conditions
and the tank venting system.
Warning!
Check for fuel leakage
while refueling and dur-
ing 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 cloth-
ing. If this happens, change your
clothing immediately.
Warning!
In order to reduce the risk of fuel spill-
age and fire from an improperly
tightened fuel cap, correctly position
and tighten the fuel cap in the fuel tank
opening.
001BA220 KN
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 correspond-
ing 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.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
001BA227 KN

MS 291 C-Q
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NTo 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.
NIf 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.
Screw Cap
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.)
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 sections "Kickback" and
the "ANSI B 175.1-2000 chain saw
kickback standard" below.
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!
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.
001BA226 KN
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.
Warning!
Never operate your power tool if it is
damaged, improperly adjusted or main-
tained, 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.
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 man-
ual. 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!
Warning!
To reduce the risk of fire and burn inju-
ries, start the engine at least 10 feet
(3 m) from the fueling spot, outdoors
only.