To reduce the risk of kickback injury use
STIHL reduced kickback bar and STIHL PM 1
(3/8" Picco) or RM 2 3/8" or RM 2 (0,325")
chain depending on sprocket 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 PM 1 (Picco
de 3/8 pulg) o RM 2 (3/8 pulg) o RM 2 (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.
MS 310, 390
Warning!
This saw is capable of severe kickback which
may cause serious or fatal injury. Only for
users with extraordinary cutting needs and
experience and training dealing with kickback.
Chainsaws with significantly reduced kickback
potential are available. STIHL recommends
the use of STIHL reduced kickback bar and
low kickback chain.
Advertencia!
Esta sierra es capaz de causar contragolpes
severos, los cuales pueden causar lesiones
graves o mortales. Sólo es apta para usuarios
con necesidades extraordinarias de corte y
mucha experiencia y capacitación en el
manejo de los contragolpes. Existen sierras
con un potencial mucho menor de causar
contragolpes. STIHL recomienda usar una
barra y cadena de contragolpe reducido de
STIHL.
Contents
English / USA
Guide to Using this Manual .............. 2
Some Important Safety
Precautions for Chain Saw Users ..... 3
Safety Precautions ........................... 5
Mounting the Bar and Chain ........... 26
Tensioning the Saw Chain .............. 28
Checking Chain Tension ................. 28
BA_SE_102_006_01_08.fmPrinted on chlorine-free paper.
Allow only persons who understand this
Manual to operate your chainsaw.
To receive maximum performance and
satisfaction from your STIHL chainsaw,
it is important that you read and
understand
precautions,
using your chainsaw.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
Manual.
the maintenance and safety
starting on page 3, before
!Warning!
Because a chainsaw 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.
STIHL's philosophy is to continually
improve all of its products. As a result,
engineering changes and improvements
are made from time-to-time. If the
operating characteristics or the
appearance of your chainsaw differs
from those described in this Manual,
please contact your STIHL dealer for
information and assistance.
All the pictograms attached to the
machine are shown and explained in
this manual.
The operating and handling instructions
are supported by illustrations.
Symbols in text
The individual steps or procedures
described in the manual may be marked
in different ways:
:A bullit marks a step or procedure
without direct reference to an
illustration.
A description of a step or procedure that
refers directly to an illustration may
contain item numbers that appear in the
illustration.
Example:
Loosen the screw (1)
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 described below:
Warning where there is a risk of an
accident or personal injury or
serious damage to property.
Caution where there is a risk of
damaging the machine or its
individual components.
Note or hint which is not essential
for using the machine, but may
improve the operator’s understanding of the situation and result
in better use of the machine.
Note or hint on correct procedure in
order to avoid damage to the
environment.
Equipment and features
This instruction manual may refer to
several models with different
features. Components that are not
installed on all models and related
applications are marked with an
asterisk (*). Such components may
be available as special accessories
from your STIHL dealer.
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. If the
operating characteristics or the
appearance of your machine differ from
those described in this manual, please
contact your STIHL dealer for
assistance.
Therefore some changes, modifications
and improvements may not be covered
in this manual.
2
MS 290, 310, 390
Some Important Safety Precautions for Chain Saw Users
English / USA
A.
A Summary of Warnings on
kickback and other Selected
Risks – Taken Primarily from
ANSI B 175.1 (See also the
“Safety Precautions“ section of
this Owner’s Manual)
!Warning!
Kickback may occur when the nose or
tip of the guide bar touches an object, or
when the wood closes in and pinches
the saw chain in the cut. Tip contact in
some cases may cause a lightning fast
reverse reaction, kicking the guide bar
up and back towards the operator.
Pinching the saw chain along the top of
the guide bar may push the guide bar
rapidly back towards the operator. Either
of these reactions may cause you to lose
control of the saw which could result in
serious personal injury.
Section 5.11 of ANSI B 175.1-2000 sets
certain performance and design criteria
related to chainsaw kickback. STIHL has
developed a color code system using
green and yellow to help you select a
powerhead, bar and chain combination
that complies with the kickback
requirements of the ANSI Standard.
See the sections entitled "Safety
Precautions" and "Specifications" of this
manual.
Do not rely exclusively upon the safety
devices built into your saw. As a
chainsaw user, you should take several
steps to keep your cutting jobs free from
accident or injury.
1. With a basic understanding of
kickback, you can reduce or
eliminate the element of surprise.
Sudden surprise contributes to
accidents.
2. Keep a good firm grip on the saw
with both hands, the right hand on
the rear handle, and the left hand on
the front handle, when the engine is
running. Use a firm grip with thumbs
and fingers encircling the chainsaw
handles. A firm grip will help you
reduce kickback and maintain
control of the saw. Don't let go.
3. Make sure the area in which you are
cutting is free from obstructions. Do
not let the nose of the guide bar
contact a log, branch, or any other
obstruction that could be hit while
you are operating the saw.
4. Cut at high engine speeds.
5. Do not overreach or cut above
shoulder height.
6. Follow manufacturer's sharpening
and maintenance instructions for
the saw chain.
7. Only use replacement bars and
chains specified by the
manufacturer or the equivalent.
8. Reduced kickback bars and low
kickback chains are designed to
reduce the risk of kickback injury.
Ask your STIHL dealer about these
devices.
B.
Other Safety Precautions
!Warning!
1. Do not operate a chainsaw with one
hand! Serious injury to the operator,
helpers, bystanders, or any
combination of these persons may
result from one-handed operation. A
chainsaw is intended to be used
with two hands.
2. Do not operate a chainsaw when
you are fatigued.
3. Use safety footwear; snug-fitting
clothing; protective gloves; and eye,
hearing, and head protection
devices.
3MS 290, 310, 390
English / USA
4. Use caution when handling fuel.
Move the chainsaw at least 10 feet
(3 m) from the fueling point before
starting the engine.
5. Do not allow other persons to be
near the chainsaw when starting or
cutting with the chainsaw. Keep
bystanders and animals out of the
work area.
6. Do not start cutting until you have a
clear work area, secure footing, and
a planned retreat path from the
falling tree.
7. Keep all parts of your body away
from the saw chain when the engine
is running.
8. Before you start the engine, make
sure that the saw chain is not
contacting anything.
9. Carry the chainsaw with the engine
stopped, the guide bar and saw
chain to the rear, and the muffler
away from your body.
10. Do not operate a chainsaw that is
damaged, improperly adjusted, or
not completely and securely
assembled. Be sure that the saw
chain stops moving when the
throttle trigger is released.
11. Shut off the engine before setting
the chainsaw down.
12. Use extreme caution when cutting
small size brush and saplings
because slender material may catch
the saw chain and be whipped
toward you or pull you off balance.
13. When cutting a limb that is under
tension be alert for springback so
that you will not be struck when the
tension in the wood fibers is
released.
14. Keep the handles dry, clean, and
free of oil or fuel mixture.
15. Operate the chainsaw only in wellventilated areas.
16. Do not operate a chainsaw in a tree
unless you have been specifically
trained to do so.
17. All chainsaw service, other than the
items listed in the Owner's Manual
maintenance instructions, should be
performed by competent chainsaw
service personnel.(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).
18. When transporting your chainsaw,
use the appropriate chain guard
(scabbard).
Other important safety precautions are
contained in the body of the Owner's
Manual, especially in the Safety
Precautions.
Note:
When using a chainsaw for logging
purposes, refer to the Code of Federal
Regulations, Parts 1910 and 1928.
4
MS 290, 310, 390
Safety Precautions
English / USA
The use of any chainsaw
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. At full throttle,
the chain speed can reach 45 mph
(20 m/s). It is important that you read,
fully understand and observe the
following safety precautions and
warnings. Read the Owner's Manual
and the Safety Precautions periodically.
Pay special attention to the section on
reactive forces.
!Warning!
Reactive forces, including kickback, can
be dangerous. Careless or improper use
of any chainsaw may cause serious or
fatal injury.
All safety precautions that are generally
observed when working with an axe or a
hand saw also apply to the operation of
chainsaws. However, because a
chainsaw is a high-speed, fast-cutting
power tool, special safety precautions
must be observed to reduce the risk of
personal injury.
Have your STIHL dealer show you how
to operate your chainsaw. Observe all
applicable local safety regulations,
standards and ordinances.
!Warning!
Minors should never be allowed to use a
chainsaw. Bystanders, especially
children, and animals should not be
allowed in the area where a chainsaw is
in use. Never let the saw run
unattended. Store it in a locked place
away from children and empty the fuel
tank before storing for longer than a few
days.
Do not lend or rent your
chainsaw without the
Owner`s Manual. Be sure
that anyone using your
saw reads and
understands the
information contained in this manual.
These safety precautions and warnings
apply to the use of all STIHL chainsaws.
Different models may have different
parts and controls. See the appropriate
section of your Owner's Manual for a
description of the controls and function
of the parts of your model saw.
Safe use of a chainsaw involves
1. the operator
2. the saw
3. the use of the saw.
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol) which might impair vision,
dexterity or judgement.
Do not operate a chainsaw when you
are fatigued. Be alert - If you get tired
while operating your chainsaw, take a
break. Tiredness may result in loss of
control. Working with any chainsaw can
be strenuous. If you have any condition
that might be aggravated by strenuous
work, check with your doctor before
operating a chainsaw.
!Warning!
Prolonged use of chainsaws (or other
machines) exposing the operator to
vibrations may produce whitefinger
disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
5MS 290, 310, 390
English / USA
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:
–Many STIHL models are available
with an anti-vibration (AV) system
designed to reduce the
transmission of vibrations created
by the engine and cutting
attachment to the operator's hands.
An AV system is recommended for
those persons using chainsaws on
a regular or sustained basis.
–Wear gloves and keep your hands
warm. Heated handles, which are
available on most STIHL powerheads, are recommended for cold
weather use.
–Keep the saw chain sharp and the
saw, including the AV system, well
maintained. A dull chain will increase cutting time, and pressing a
dull chain through wood will increase the vibrations transmitted to
your hands. A saw with loose
components or with damaged or
worn AV buffers will also tend to
have higher vibration levels.
–Maintain a firm grip at all times, but
do not squeeze the handles with
constant, excessive pressures.
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 monitor closely the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
!Warning!
The ignition system of your 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 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. Avoid loosefitting jackets, scarfs,
neckties, jewelry, flared or
cuffed pants, unconfined long hair or
anything that could become entangled
with the saw or brush. Wear overalls or
jeans with a reinforced cut retardant
insert or cut retardant chaps.
Protect your hands with
gloves when handling
saw and saw chain.
Heavy-duty, nonslip
gloves improve your grip
and protect your hands.
Good footing is most
important in chainsaw
work. Wear sturdy boots
with nonslip soles. Steel-
toed safety boots are
recommended.
Never operate a chainsaw unless
wearing goggles or properly fitted safety
glasses with adequate top and side
protection complying with your national
standard.
6
MS 290, 310, 390
English / USA
Wear an approved safety
hard hat to protect your
head. Chainsaw noise
may damage your
hearing. Always wear
sound barriers (ear plugs
or ear mufflers) to protect your hearing.
Continual and regular users should have
their hearing checked regularly.
THE SAW
Parts of the chainsaw; for illustrations
and definitions of the parts see the
chapter on "Main Parts of Saw".
!Warning!
Never modify a chainsaw in any way.
Only attachments and parts supplied by
STIHL or expressly approved by STIHL
for use with the specific STIHL saw
models are authorized. Although certain
unauthorized attachments are usable
with the STIHL powerhead, their use
may, in fact, be extremely dangerous.
THE USE OF THE SAW
Transporting the chainsaw
!Warning!
Always stop the engine before putting a
chainsaw down or carrying it. Carrying a
chainsaw with the engine running is
extremely dangerous.
Accidental acceleration of the engine
can cause the chain to rotate. During
operation, the powerhead muffler and
the material around it reach extremely
high temperatures. Avoid touching the
hot muffler, you could receive serious
burns.
By hand: When carrying your saw by
hand, the engine must be stopped and
the saw must be in the proper position.
Grip the front handle and place the
muffler away from the body.
001BA115 KN
The chain guard (scabbard) should be
over the chain and the guide bar, which
should point backwards. When carrying
your saw, the bar should be behind you.
By vehicle: When transporting in a
vehicle, keep chain and bar covered with
the chain guard. Properly secure your
saw to prevent turnover, fuel spillage
and damage to the saw or vehicle.
Preparation for the use of the saw
Take off the chain guard and inspect for
safety in operation. For assembly, follow
the procedure described in the chapter
"Mounting the Bar and Chain" of your
Owner's Manual.
STIHL Oilomatic chain, guide bar and
sprocket must match each other in
gauge and pitch.
Before replacing any bar and chain, see
the sections on "Specifications",
"Kickback" and the "ANSI B 175.1-2000
chainsaw kickback standard" in this
manual.
7MS 290, 310, 390
English / USA
!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. 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!
Fueling
Your STIHL chainsaw uses an oil-gasoline mixture for fuel (see chapter "Fuel"
of your Owner's Manual).
!Warning!
Gasoline is an extremely flammable fuel.
If spilled or ignited by a spark or other
ignition source, it can cause fire and
serious 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 chainsaw. Note that
combustible fuel vapors
may be vented from the
fuel system.
Fueling Instructions
!Warning!
Fuel your chainsaw in well-ventilated
areas, outdoors only. Always shut off the
engine and allow it to cool before
refueling. Gasoline vapor pressure may
build up inside the gas tank depending
on the fuel used, the weather conditions,
and the venting system of the tank. In
order to reduce the risk of burns or other
personal injury from escaping gas vapor
and fumes, remove the fuel filler cap on
the STIHL product carefully so as to
allow any pressure build-up in the tank
to release slowly. Never remove fuel
filler cap while engine is running.
Select bare ground for fueling and move
at least 10 feet (3 m) from fueling spot
before starting the engine. Wipe off any
spilled fuel before starting your saw, and
check for leakage.
!Warning!
Check for fuel leakage while refueling
and during operation. If fuel or oil
leakage is found, do not start or run the
engine until leak is fixed and 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 have different fuel
caps.
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.
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
triangular marks on the grip of the cap
and on the fuel tank opening lining up.
Using the grip, turn the cap firmly
clockwise as far as it will go (approx. a
quarter turn).
8
MS 290, 310, 390
Fold the grip flush with the
top of the cap. 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 neck,
the cap is not properly seated and
tightened and you must repeat the
above steps.
Slotted 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 fuel filler cap by hand
with as much force 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 "Fueling" chapter in your Owner's
Manual.
Starting
The chain brake must be engaged when
starting the saw.
!Warning!
Your chainsaw is a one-person saw. Do
not allow other persons to be near the
running chainsaw. Start and operate
your saw without assistance. For
specific starting instructions, see the
appropriate section of the Owner's
Manual. Proper starting methods reduce
the risk of injury. 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 chainsaw.
With the first recommended method,
the chainsaw is started on the ground.
Make sure the chain brake is engaged
(see "Chain Brake" chapter in your
Owner's Manual) and place the
chainsaw on firm ground or other solid
surface in an open area. Maintain good
balance and secure footing.
English / USA
001BA113 KN
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 chainsaw 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
chainsaw 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.
001BA114 KN
9MS 290, 310, 390
English / USA
!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 chainsaw
when the guide bar is in a cut or kerf.
!Warning!
When you pull the starter grip, do not
wrap the starting rope around your
hands. Do not allow the grip to snap
back, but guide the starter rope slowly
back to permit the rope to rewind
properly. Failure to follow this procedure
may result in injury to hand or fingers
and may damage the starter
mechanism.
Important adjustments
!Warning!
To reduce the risk of personal injury from
loss of control or contact with the
running chain, do not use a saw with
incorrect idle adjustment. At correct idle
speed, the chain should not rotate. For
directions to adjust idle speed, see the
appropriate section of your Owner's
Manual. If you cannot set the correct idle
speed, have your STIHL dealer check
your saw and make proper adjustments
or repairs. After adjusting a chain, start
the saw, let the engine run for a while,
then switch engine off and recheck chain
tension. Proper chain tension is very
important at all times.
Catalytic converter
!Warning!
Some STIHL chainsaw models 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, specific safety precautions must
be observed.
!Warning!
Since a muffler with a
catalytic converter cools
down less rapidly than
conventional mufflers,
never set your chainsaw
down on or near dry
brush, grass, wood chips or other
combustible materials while it is still hot.
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!
To reduce the risk of fire or burn injury,
let the unit cool down before refueling
your chainsaw after use.
!Warning!
Never disassemble or modify your
muffler. The muffler could be damaged
and cause an increase in heat radiation
or sparks, thereby increasing the risk of
fire or burn injury. You may also
permanently damage the engine. Have
your muffler serviced and repaired by
your STIHL Servicing Dealer only.
10
MS 290, 310, 390
English / USA
!Warning!
To reduce the risk of fire or burn injury,
keep the area around the muffler clean.
Remove all debris such as pine needles,
branches or leaves.
!Warning!
An improperly mounted or damaged
cylinder housing or a damaged/
deformed muffler shell may interfere
with the cooling effect of the catalytic
converter. To reduce the risk of fire or
burn injury, do not continue work with a
damaged or improperly mounted
cylinder housing 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.
Working Conditions
Operate the chainsaw under good
visibility and daylight conditions only.
!Warning!
Your chainsaw produces
poisonous exhaust fumes
as soon as the
combustible engine is
running. These gases
(e.g. carbon monoxide)
may be colorless and odorless. To
reduce the risk of serious or fatal injury
from breathing toxic fumes, never run
the chainsaw indoors or in poorly
ventilated locations. Ensure proper
ventilation when working in trenches or
other confined areas.
!Warning!
Use of this product (including sharpening the saw chain) can generate dust,
mists and fumes containing chemicals
known to cause respiratory disease,
cancer, birth defects, or other
reproductive harm. If you are unfamiliar
with the risks associated with the
particular dust, mist or fume at issue,
consult your employer, governmental
agencies such as OSHA and NIOSH
and other sources on hazardous
materials. California and some other
authorities, for instance, have published
lists of substances known to cause
cancer, reproductive toxicity, etc. Control
dust (such as sawdust), mists (such as
oil mist from chain lubrication) and
fumes at the source where possible.
In this regard use good work practices
and follow the recommendations of
OSHA / NIOSH and occupational and
trade associations. When the inhalation
of toxic dust, mists and fumes cannot be
eliminated, the operator and any
bystanders should always wear a
respirator approved by NIOSH / MSHA
for the type substance at issue.
!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. Do not cut or disturb asbestos,
asbestos containing products (e.g.
asbestos containing drywall or other
construction products), or products such
as pipes which are wrapped or covered
with asbestos insulation. If you have any
reason to believe that you might be
cutting asbestos, immediately contact
your employer or a local OSHA
representative.
11MS 290, 310, 390
English / USA
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. Don't work alone. Keep within
calling distance of others in case help is
needed.
Your chainsaw 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 chainsaw with a damaged
or missing catcher.
Inspect buffers periodically. Replace
damaged, broken or excessively worn
buffers 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. Buffers should always
be replaced in sets. If you have any
questions as to whether the buffers
should be replaced, consult your STIHL
servicing dealer.
!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.
!Warning!
Avoid stumbling on obstacles such as
stumps, roots or rocks and watch out for
holes or ditches. Clear the area where
you are working. Be extremely cautious
when working on slopes or uneven
ground. There is increased danger of
slipping on freshly debarked logs.
!Warning!
To reduce the risk
of serious or fatal
injury to the
operator or
bystanders, never
use the saw with one hand.
You cannot control reactive forces and
you may lose control of the saw, which
can result in the skating or bouncing of
the bar and chain 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.
001BA087 LÄ
Cutting Instructions
Grip: Always hold the saw firmly with
both hands when the engine is running.
Place your left hand on front handle bar
and your right hand on rear handle and
throttle trigger. Left-handers should
follow these instructions too.
Wrap your fingers tightly around the
handles, keeping the handles cradled
between your thumb and forefinger. 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). Make sure your chainsaw
handles and grip are in good condition
and free of moisture, pitch, oil or grease.
!Warning!
Do not operate your chainsaw with the
starting throttle lock engaged. Cutting
with the starting throttle lock engaged
does not permit the operator proper
control of the saw or chain speed.
12
MS 290, 310, 390
English / USA
!Warning!
Never touch a chain with your hand or
any part of your body when the engine is
running, even when the chain is not
rotating. The chain continues to rotate
for a short period after the throttle trigger
is released.
!Warning!
Do not cut any material other than wood
or wooden objects. Use your saw for
chainsawing only. It is not designed for
prying or shoveling away limbs, roots or
other objects. 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!
In order to keep control of your saw,
always maintain a firm foothold.
001BA018 LA
Never work on a ladder, or on any other
insecure support. Never use the saw
above shoulder height.
!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 chainsaw in a cramped
environment and have taken proper
precautions to avoid injury from falling
limbs or branches.
Position the chainsaw 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.
Don't put pressure on the saw when
reaching the end of a cut. The pressure
may cause the bar and rotating chain to
001BA031 KN
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.
Reactive forces including kickback
!Warning!
Reactive forces may occur any time the
chain is rotating. Reactive forces can be
dangerous! In any chainsaw,
001BA082 KN
13MS 290, 310, 390
English / USA
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 like a log or branch or is
pinched, there active forces may occur
instantly. These reactive forces may
result in loss of control which may, in
turn, cause serious or fatal injury. An
understanding of the causes of these
reactive forces may help you avoid loss
of control.
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.
001BA093 LÄ
The reaction of the cutting force of the
chain causes a rotational force on the
chainsaw in the direction opposite to the
chain movement. This may fling the bar
up and back 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.
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.
001BA035 KN
ANSI B 175.1-2000 chainsaw
kickback standard
Section 5.11 of ANSI standard
B 175.1-2000, sets certain performance
and design criteria related to chainsaw
kickback.
To comply with section 5.11 of ANSI
B 175.1-2000:
14
MS 290, 310, 390
English / USA
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 inch (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 175.12000 does not automatic-ally 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
inch (62 cm³) displacement to comply
with the computed kickback angle
requirements of § 5.11 of ANSI B 175.12000 use only the following cutting
attachments:
–bar and chain combinations listed
as complying in the "Specifications"
section of the Owner's 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
power-head with green labeled reduced
kickback bars and low kickback chains.
!Warning!
To reduce the risk of injury, stop using
the saw immediately if the chain brake
does not function properly. Take the saw
to your local STIHL Service Center! Do
not use the saw until the problem has
been rectified (see the section "Chain
Brake").
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. The
Quickstop is available as standard
equipment on your STIHL chainsaw and
is available for installation on most older
STIHL saws. Ask your dealer to retrofit
your older model saw with a chain brake.
15MS 290, 310, 390
English / USA
When a kickback occurs, the guide bar
may rotate around the front handle. If the
cutting position is such that the
operator's left hand is gripping the front
handle behind the hand guard, and if the
left hand rotates around the front handle
and makes a sufficiently forceful contact
with the front hand guard, which is the
Quickstop activating lever, this contact
will activate the Quickstop. The chain
brake on most new model STIHL
chainsaws can also be activated by
inertia. See the chapter entitled "Chain
Brake" of your Owner's Manual.
!Warning!
Never operate your chainsaw without a
front hand guard. In a kickback situation
this guard helps protect your left hand or
other parts of your body. In addition,
removal of the hand guard on a saw
equipped with a 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
001BA036 KN
and in good working order. See the
chapter entitled "Chain Brake" and
"Maintenance, Repair and Storing" of
your Owner's Manual. 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 chainsaw above idle
speed for more than 3 seconds when the
chain brake is engaged or 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". Also make sure that the chain is
not turning at idle speed (see above
"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
16
MS 290, 310, 390
English / USA
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
codesystem 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 inch (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 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 chainsaw users.
Please ask your STIHL dealer to
properly match your powerhead with the
appropriate bar/chain combinations to
reduce the risk of kickback injury. Green
labeled bars and chains are
recommended for all powerheads. See
your "STIHL Bar and Chain Information"
leaflet for details.
!Warning!
Use of other, non-listed bar/chain
combinations may increase kickback
forces and increase 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 (Safety
Requirements for Gasoline-Powered
ChainSaws) when tested in its original
condition on a selected representative
sample of chainsaws below 3.8 cubic
inch (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.
!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.
17MS 290, 310, 390
English / USA
Reduced kickback bar
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, and may result in
higher kickback forces.
Bow Guides
!Warning!
Do not mount a bow guide on any STIHL
chainsaw. Any chainsaw equipped with
a bowguide 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 chainsaw firmly with both
hands and maintain a secure grip.
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 when cutting
small, tough limbs, small size brush
and saplings which may easily catch
the chain.
4Don'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 chainsaw.
A
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 and 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. Pull-in may also be prevented by
using wedges to open the kerf or
cut.
001BA037 KN
18
MS 290, 310, 390
B
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 drives the saw 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.
Cutting Techniques
Felling
Felling is cutting down a tree.
Before felling a tree, consider carefully
all conditions which may affect the
direction of fall, including:
001BA038 KN
The intended direction of the fall.
The natural lean of the tree.
Any unusually heavy limb structure.
Surrounding trees and obstacles.
The wind direction and speed.
!Warning!
Always observe the general condition of
the tree. Inexperienced users should
never attempt to cut trees which are
decayed or rotted inside or which 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.
English / USA
1
11
Felling Instructions:
When felling, maintain a distance of at
least 21/2 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.
/
2
1
/
2
2
!Warning!
The noise of your engine may drown any
warning call.
!Warning!
There are a number of factors that may
affect and change the intended direction
of fall, e.g. wind, lean of tree, 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.
001BA088 LÄ
19MS 290, 310, 390
English / USA
A
B
45°
45°
B
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.
20
001BA040 KN
Buttress roots
If the tree has large buttress roots, cut
into the largest buttress vertically first
(horizontally next) and remove the
resulting piece.
001BA041 KN
Gunning sight
When making the felling notch, use the
gunning sight on the shroud and housing
to check the required direction of fall:
:Position the saw so that the gunning
sight points exactly in the direction
you want the tree to fall.
MS 290, 310, 390
001BA019 KN
A
English / USA
Conventional cut
A = felling notch - determines the
direction of the fall
For a conventional cut:
:Properly place felling notch
perpendicular to the line of fall,
close to the ground
:Cut down at app. 45-degree angle
to a depth of about 1/5 to 1/4 of the
trunk diameter
:Make second cut horizontal
:Remove resulting 45-degree piece
001BA052 KN
Open-face technique
A = felling notch - determines the
direction of the fall
For an open-face cut:
:Properly place felling notch
perpendicular to the line of fall,
close to the ground
:Cut down at app. 50-degree angle
to a depth of app.1/5 to 1/4 of the
trunk diameter
:Make second cut from below at app.
40 degree angle
:Remove resulting 90-degree piece
001BA042 LÄ
Making sapwood cuts
:For medium sized or larger trees
make cuts at both sides of the trunk,
:at same height as subsequent
felling cut.
: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.
001BA043 KN
21MS 290, 310, 390
English / USA
C
B
B
B = Felling cut
Conventional and open-face technique:
:Begin 1 to 2 inches (2,5 to 5 cm)
higher than centre of felling notch
:Cut horizontally towards the felling
notch
:Leave approx.1/10 of diameter
uncut. This is the hinge
: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.
!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.
C
001BA044 KN
C = Hinge
:Helps control the falling tree
:Do not cut through the hinge -you
could lose control of the direction of
the fall
!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.
001BA045 KN
!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.
Felling cut for small diameter trees:
simple fan cut
Engage the bumper spikes of the
chainsaw 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.
001BA046 KN
22
MS 290, 310, 390
1
3
2
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.
1
001BA047 KN
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.
English / USA
3
001BA089 LÄ
2
First, cut a large, wide felling notch.
Make a plunge cut in the centre of the
notch.
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
001BA048 KN
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.
23MS 290, 310, 390
English / USA
0
If you are inexperienced with a
chainsaw, plunge-cutting should not be
attempted. Seek the help of a
professional.
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.
!Warning!
1. 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.
001BA033 KN
2. Cut only one log at a time.
3. 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.
4. 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.
01BA051 LÄ
24
MS 290, 310, 390
English / USA
0
5. Logs under strain: Risk of pinching!
Always start relieving cut (1) at
compression side (A).Then make
bucking cut (2) at tension side (B).
If the saw pinches, stop the engine
and remove it from the log.
6. 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.
7. 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 claim
warranty for a component which has
not been serviced or maintained
properly or if nonapproved
replacement parts were used, STIHL
may deny warranty.
Never operate a chainsaw that is
damaged, improperly adjusted or not
completely or securely assembled.
Follow the maintenance and repair
instructions in the appropriate section of
01BA050 LÄ
your Owner's Manual, especially those
in the chapters "Mounting the Bar and
Chain", "Maintaining and Sharpening"
and "Chain Brake".
!Warning!
Use only STIHL replacement parts for
maintenance and repair. Use of parts
manufactured by others may cause
serious or fatal injury.
!Warning!
Always stop the engine and ensure that
the chain is stopped before making any
adjustments, maintenance or repair
work,
changing the saw chain or cleaning the
saw. Do not attempt any maintenance or
repair work not described in your
Owner's Manual. Have such work
performed at your STIHL service shop
only.
!Warning!
Never test the ignition system with
ignition wire terminal removed from
sparkplug or with unseated spark plug,
since uncontained sparking may cause
a fire.
!Warning!
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. 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
attached.) A loose connection between
spark plug terminal and ignition wire
connector in the boot may create arcing
that could ignite combustible fumes and
cause a fire. Keep spark plug clean, and
make sure ignition lead is in good
condition.
!Warning!
Do not operate your chainsaw if the
muffler is damaged, missing or modified.
An improperly maintained muffler will
increase the risk of fire and hearing loss.
Never touch a hot muffler or burn will
25MS 290, 310, 390
English / USA
Mounting the Bar and Chain
result. If your muffler was equipped with
a spark-arresting screen to reduce the
risk of fire (e. g. in the USA, Canada and
Australia), 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-tocut 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 chainsaw to properly perform its
function of reducing the risk of kickback
and other injuries, it must be properly
maintained. Like an automobile brake, a
chainsaw 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
chainsaw 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 chainsaw 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 please refer to the
maintenance chart and to the warranty statement near the end of this manual.
Additionally, the daily maintenance
schedule for your chainsaw set forth in
your STIHL Owner's Manual should be
strictly followed.
Store chainsaw 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 this manual).
1
a
t = a : 2
You can run chains of different pitches
on this chainsaw – depending on the
chain sprocket (see “Specifications”):
The chain pitch (1) must match the pitch
of the sprocket and the guide bar (for
Rollomatic). The drive link gauge (2)
must match the bar groove width (3).
The pitch is marked on the chain
sprocket and guide bar in inches
(e.g. 3/8 or .325). The groove width
is marked on the guide bar in
millimeters (e.g. 1.6).
If non-matching components of the
wrong pitch or drive link gauge are
run together on the same machine
they may be damaged beyond
repair after a short period of
operation.
2
3
001BA105 KN
26
MS 290, 310, 390
English / USA
6
9
7
7
10
8
:Unscrew the nuts and take off the
chain sprocket cover.
4
5
:Turn screw (4) counterclockwise
until the tensioner slide (5) butts
against left end of housing slot.
143BA034 KN
:Disengage the chain brake: Pull
hand guard (6) toward front handle.
001BA107 KN
Wear work gloves to protect your
hands from the sharp cutters.
:Fit the chain – start at the bar nose.
001BA108 KN
:Fit the guide bar over the studs (7) –
cutting edges on top of bar must
point to right – and engage the
peg of the tensioner slide in locating
hole (8) – place the chain over
sprocket (9) at the same time.
:Now turn tensioning screw (10)
clockwise until there is very little
chain sag on the underside of the
bar – and the drive link tangs are
143BA003 KN
located in the bar groove.
:Refit the sprocket cover –
and screw on the nuts only fingertight.
:Go to “Tensioning the Saw Chain”.
001BA109 KN
27MS 290, 310, 390
English / USA
Tensioning the Saw Chain
1
Retensioning during cutting work:
:Shut off the engine first –
and then loosen the nuts.
:Hold the bar nose up and use
screwdriver to turn tensioning screw
(1) clockwise until chain fits snugly
against the underside of the bar.
:While still holding the bar nose up,
tighten down the nuts firmly.
:Go to chapter “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 "Operating
Instructions".
Checking Chain Tension
133BA024 KN
:Shut off the engine.
:Wear work gloves.
:Chain must fit snugly against the
underside of the bar – and, with the
chain brake disengaged, it must still
be possible to pull the chain along
the bar by hand.
: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
"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 two-stroke engine requires a
mixture of high-quality gasoline and
quality two-stroke air cooled engine oil.
Use mid-grade unleaded gasoline with a
143BA007 KN
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
nationally recognized high-quality
unleaded gasoline!
28
MS 290, 310, 390
Fueling
English / USA
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 50:1 two-stroke
engine oil since it is specially formulated
for use in STlHL 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,
chainsaws, 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.
Gasoline
Oil (STIHL 50:1 or
equivalent high-quality oils)
US gal.US fl.oz
12.6
2 1/26.4
512.8
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
001BA159 KN
Before fueling, clean the filler cap and
the area around it to ensure that no dirt
falls into the tank.
Always position the machine so that the
filler cap points upwards.
Always thoroughly shake the mixture in
the canister before fueling your
machine.
In order to reduce the risk of burns
or other personal injury from
escaping gas vapor and fumes,
remove the fuel filler cap carefully
so as to allow any pressure build-up
in the tank to release slowly.
29MS 290, 310, 390
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