Stihl MS 290 User Manual
STIHL MS 290, 310, 390
STIH)
Instruction Manual
Manual de instrucciones
MS 290
Warning!
To reduce the risk of kickback injury use
STIHL reduced kickback bar and STIHL RSC3
(3/8") or RMC3 (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 RSC3
3/8 pulg) o 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.
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
Safety Precautions and Working
Techniques ....................................... 3
Mounting the Bar and Chain ........... 26
Tensioning the Saw Chain .............. 27
Checking Chain Tension ................. 28
Fuel ................................................ 28
BA_SE_102_006_01_14.fmPrinted on chlorine-free paper.
Fueling ............................................ 29
Chain Lubricant .............................. 30
Filling Chain Oil Tank ...................... 31
Checking Chain Lubrication ........... 31
Chain Brake .................................... 32
Winter Operation ............................ 33
Information Before You Start .......... 34
Starting / Stopping the Engine ........ 35
Operating Instructions .................... 38
Oil Quantity Control ........................ 39
Taking Care of Guide Bar ............... 39
Air Filter System ............................. 40
Cleaning Air Filter ........................... 40
Motor Management ........................ 41
Adjusting the Carburetor ................ 41
Spark Arresting Screen in
Muffler.............................................. 43
Checking the Spark Plug ................ 43
Replacing Starter Rope
Printing inks contain vegetable oils; paper can be recycled.
and Rewind Spring ......................... 44
Storing the Machine ........................ 46
Checking and Replacing
Chain Sprocket ............................... 47
Maintaining and Sharpening
Saw Chain ...................................... 48
Maintenance Chart ......................... 52
Parts and Controls .......................... 54
Specifications ................................. 56
Special Accessories ....................... 58
Ordering Spare Parts ...................... 58
Maintenance and Repairs ............... 58
STIHL Incorporated Federal
Emission Control Warranty
Statement ....................................... 59
Trademarks .................................... 61
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.
STIHl
© ANDREAS STIHL AG & Co. KG, 2007
0458 209 8621 A. M18. K7. CP. Printed in USA
1MS 290, MS 310, MS 390
English / USA
Guide to Using this Manual
Pictograms
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 bullet 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, MS 310, MS 390
Safety Precautions and
Working Techniques
English / USA
Because a chainsaw 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 axe or a hand saw
also apply to the operation of chainsaws.
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. At full throttle, the chain
speed can reach 67 mph (30 m/s).
Use your chainsaw only for cutting
wooden objects. It must not be used for
any other purposes, since such misuse
may result in an accident or 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
chainsaws. 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 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, 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.
3MS 290, MS 310, MS 390
English / USA
!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.
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 buffers 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.
4
MS 290, MS 310, MS 390
English / USA
!Warning!
Wear an approved safety
hard hat to reduce the risk
of injury to your head.
Chainsaw 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.
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.
STIHL offers a wide range of protective
clothing and equipment.
THE POWER TOOL
For illustrations and definitions of the
power tool parts see the chapter on
“Main Parts and Controls.”
!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.
001BA115 KN
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.
5MS 290, MS 310, MS 390
English / USA
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 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 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.
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.
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).
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
opening, the cap is not properly seated
and tightened and you must repeat the
above steps.
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 "Fueling" chapter in your instruction
manual.
6
MS 290, MS 310, MS 390
English / USA
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!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger interlock, 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
maintained, or not completely or
securely assembled.
!Warning!
Check that the spark plug boot is secure
– 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 chainsaw
kickback standard" below.
!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!
To reduce the risk of fire and burn
injuries, start the engine at least 10 feet
(3 meters) 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.
!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 chainsaw.
7MS 290, MS 310, MS 390
English / USA
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
instruction manual) and place the
chainsaw 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.
001BA113 KN
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.
!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
001BA114 KN
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.
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.
8
MS 290, MS 310, MS 390
English / USA
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.
Your right hand should grip the rear
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.
001BA087 LÄ
9MS 290, MS 310, MS 390
English / USA
!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 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.
Never 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.
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 chainsaw 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!
001BA082 KN
(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.
As soon as the engine is
running, this product
generates toxic exhaust
fumes containing
chemicals, such as
unburned hydrocarbons
10
MS 290, MS 310, MS 390
English / USA
!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.
!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
chainsaw 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 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 chain catcher.
11MS 290, MS 310, MS 390
English / USA
! Warning!
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!
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.
!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.
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.
12
MS 290, MS 310, MS 390
English / USA
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.
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 a ligtening 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.
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:
13MS 290, MS 310, MS 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 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
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 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. The
Quickstop chain brake is standard
equipment on your STIHL chainsaw.
14
MS 290, MS 310, MS 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 a properly maintained
Quickstop chain brake. The chain brake
on newer STIHL chainsaws can also be
activated by inertia. If the kickback
forces 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 chainsaw 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
001BA174 KN
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 chainsaw 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").
15MS 290, MS 310, MS 390
English / USA
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 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 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 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.
16
MS 290, MS 310, MS 390
English / USA
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.
Bow Guides
!Warning!
Do not mount a bow guide on any STIHL
chainsaw. Any chainsaw 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 chainsaw 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 chainsaw.
A = Pull-in
A
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.
001BA037 KN
17MS 290, MS 310, MS 390
English / USA
1
B = Pushback
B
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 rapidely
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.
!Warning!
001BA038 KN
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:
1
/
2
1
/
2
2
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.
1
!Warning!
The noise of your engine may drown any
warning call.
001BA088 LÄ
18
MS 290, MS 310, MS 390
B
45°
English / USA
Buttress roots
C
A
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.
If the tree has large buttress roots, cut
into the largest buttress vertically first
(horizontally next) and remove the
resulting piece.
Gunning sight
001BA040 KN
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.
001BA146 KN
C
Conventional cut
C = felling notch - determines the
direction of the fall
For a conventional cut:
: Properly place felling notch
001BA153 KN
perpendicular to the line of fall,
close to the ground.
: Cut down at approx. 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.
001BA143 KN
19MS 290, MS 310, MS 390
English / USA
D
D
Open-face technique
C = 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 approx. 50-degree
angle to a depth of approx.1/5 to
1/4 of the trunk diameter.
: Make second cut from below at
approx. 40 degree angle.
: Remove resulting 90-degree piece.
20
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.
001BA150 KN
D = Felling cut
Conventional and open-face technique:
: Begin 1 to 2 inches (2,5 to 5 cm)
higher than center 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.
MS 290, MS 310, MS 390
001BA144 KN
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.
English / USA
E
E
E = Hinge
: Helps control the falling tree.
: Do not cut through the hinge – you
could lose control of the direction of
the fall.
001BA145 KN
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.
001BA147 KN
21MS 290, MS 310, MS 390
English / USA
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.
1
2
First, cut a large, wide felling notch.
Make a plunge cut in the center of the
notch.
4
001BA148 KN
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.
22
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.
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.
MS 290, MS 310, MS 390
English / USA
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
chainsaw, 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.
23MS 290, MS 310, MS 390
English / USA
0
1
2
001BA151 KN
2
1
Bucking
Bucking is cutting a log into sections.
!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.
24
001BA033 KN
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
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.
MS 290, MS 310, MS 390
001BA152 KN
English / USA
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 maintenance
chart near the end of the instruction
manual.
!Warning!
Always stop the engine and make sure
that the chain 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.
!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 chainsaw 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 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.
25MS 290, MS 310, MS 390
English / USA
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 of the emission
control system please refer to the
maintenance chart and to the limited
warranty statement near the end of the
instruction manual.
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 the instruction manual).
Mounting the Bar and Chain
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
: 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
001BA107 KN
26
MS 290, MS 310, MS 390
English / USA
Tensioning the Saw Chain
6
9
7
7
: Disengage the chain brake: Pull
hand guard (6) toward front handle.
Wear work gloves to protect your
hands from the sharp cutters.
: Fit the chain – start at the bar nose.
10
8
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”.
1
001BA109 KN
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
Ten si on ”.
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".
133BA024 KN
27MS 290, MS 310, MS 390
English / USA
Checking Chain Tension
: 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 engine requires a mixture of highquality 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!
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.
28
MS 290, MS 310, MS 390
Fueling
English / USA
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 1/2 6.4
512.8
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
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.
Opening the cap
001BA159 KN
001BA160 KN
: Raise the grip until it is upright.
001BA161 KN
: Turn the cap counterclockwise
(approx. a quarter turn).
: Remove the filler cap.
29MS 290, MS 310, MS 390
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