STIHL FS 310 Owner's Manual
STIH)
STIHL FS 310
Instruction Manual
Manual de instrucciones
Warning!
Read and follow all safety precautions in
Instruction Manual – improper use can cause
serious or fatal injury.
Advertencia!
Lea y siga todas las precauciones de
seguridad dadas en el manual de
instrucciones – el uso incorrecto puede
causar lesiones graves o mortales.
Contents
English / USA
Guide to Using this Manual .............. 2
Safety Precautions and
Working Techniques ......................... 3
Approved Combinations of
Cutting Tool, Deflector,
Stop and Harness ........................... 19
Mounting the Bike Handle .............. 21
BA_SE_200_003_01_02.fmPrinted on chlorine-free paper.
Adjusting the Throttle Cable ........... 22
Mounting the Deflectors and
Limit Stop ........................................ 23
Mounting the Cutting Tools ............. 24
4-MIX Engine .................................. 27
Fuel ................................................ 27
Fueling ............................................ 28
Fitting the Harness ......................... 29
Balancing the Machine ................... 29
Starting / Stopping the Engine ........ 30
Operating Instructions .................... 32
Cleaning the Air Filter ..................... 33
Motor Management ........................ 33
Adjusting the Carburetor ................ 33
Printing inks contain vegetable oils; paper can be recycled.
Checking the Spark Plug ................ 35
Lubricating the Gearbox ................. 36
Replacing Starter Rope
and Rewind Spring ......................... 36
Storing the Machine ....................... 39
Sharpening
Metal Cutting Tools ......................... 40
Inspections and Maintenance
by Dealer ........................................ 40
Maintenance Chart ......................... 41
Parts and Controls ......................... 43
Specifications ................................. 45
Special Accessories ....................... 46
Maintenance and Repairs .............. 46
STIHL Incorporated
Federal Emission Control
Warranty Statement ........................ 47
STIHL Incorporated California
Exhaust and Evaporative Emissions
Control Warranty Statement ........... 49
Trademarks .................................... 51
Allow only persons who understand this
manual to operate your trimmer/
brushcutter.
To receive maximum performance and
satisfaction from your STIHL trimmer/
brushcutter, it is important that you read
and understand the maintenance and
safety precautions, starting on page 3,
before using your trimmer/brushcutter.
Contact your STIHL dealer or the STIHL
distributor for your area if you do not
understand any of the instructions in this
manual.
!Warning!
Because a trimmer/brushcutter is a highspeed cutting tool some special safety
precautions must be observed to reduce
the risk of personal injury.
Careless or improper use may cause
serious or even fatal injury. Make sure
your unit is equipped with the proper
deflector, handle and harness for the
type of cutting attachment being used.
Always wear proper eye protection.
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 trimmer/brushcutter differs
from those described in this manual,
please contact your STIHL dealer for
information and assistance.
STIHl
© ANDREAS STIHL AG & Co. KG, 2007
0458 273 8621 A. M0.2. H7. PM. Printed in USA
1FS 310
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
FS 310
Safety Precautions and
Working Techniques
English / USA
Because a trimmer/
brushcutter is a highspeed, fast-cutting power
tool sometimes equipped
with sharp cutting blades,
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 precautions periodically.
Careless or improper use may cause
serious or fatal injury.
The terminology utilized in this manual
when referring to the power tool reflects
the fact that different types of cutting
attachments may be mounted on it. The
term "trimmer" is used to designate an
FS unit that is equipped with a nylon line
head or a head with flexible plastic
blades (i.e., the Polycut head). A
"brushcutter" designates a unit
equipped with a rigid metal blade. Your
FS model may be used as either a
trimmer or a brushcutter - therefore, it is
referred to here as a "trimmer/
brushcutter." The term "clearing saw"
indicates a high-powered trimmer/
brushcutter that is particularly suited for
use with a circular saw blade to clear
saplings or small trees. FS models with
an "R" on the nameplate were originally
configured (at the time of distribution) as
a trimmer with a loop handle.
!Warning
As more fully explained later in these
Safety Precautions, to reduce the risk of
personal injury, make sure your unit is
equipped with the proper handle,
harness and deflector for the type of
cutting attachment you are using. Use
only cutting attachments that are
specifically authorized by STIHL for use
on your FS model.
Have your STIHL dealer show you how
to operate your power tool. Observe all
applicable local safety regulations,
standards and ordinances.
!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. If the rotating line or blade
comes in contact with your body, it will
cut you. When it comes in contact with
solid foreign objects such as rocks or
bits of metal, it may fling them directly or
by ricochet in the direction of bystanders
or the operator. Striking such objects
could damage the cutting attachment
and may cause blades to crack, chip or
break. Thrown objects, including broken
heads or blades, may result in serious or
fatal injury to the operator or bystanders.
STIHL does not recommend the use of
rigid blades when cutting in stony areas.
Use your trimmer/brushcutter equipped
with the appropriate cutting attachment
only for cutting grass, brush, wood and
similar material. 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.
3FS 310
English / USA
!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
trimmer/brushcutters. 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 trimmer/brushcutter
involves
1. the operator
2. the power tool
3. the use of the power tool.
THE OPERATOR
Physical Condition
You must be in good physical condition
and mental health and not under the
influence of any substance (drugs,
alcohol, etc.) which might impair vision,
dexterity or judgment. Do not operate
this machine when you are fatigued.
!Warning!
Be alert – if you get tired, take a break.
Tiredness may result in loss of control.
Working with any power tool can be
strenuous. If you have any condition that
might be aggravated by strenuous work,
check with your doctor before operating
this machine.
!Warning!
Prolonged use of a power tool (or other
machines) exposing the operator to
vibrations may produce whitefinger
disease (Raynaud's phenomenon) or
carpal tunnel syndrome.
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.
4
FS 310
English / USA
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.
Maintain a firm grip at all times, but do
not squeeze the handles with constant,
excessive pressure. Wear gloves and
keep your hands warm. 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.
The deflector provided with your power
tool will not protect the operator from all
foreign objects (gravel, glass, wire, etc.)
thrown back by the rotating cutting
attachment. Thrown objects may also
ricochet and strike the operator.
!Warning!
To reduce the risk of injury
to your eyes 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.
!Warning!
Power tool noise may
damage your hearing.
Wear sound barriers (ear
plugs or ear mufflers) to
protect your hearing.
Continual and regular
users should have their hearing checked
regularly.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
Always wear gloves when
handling the machine and
metal blades. Heavy-duty,
nonslip gloves improve
your grip and help to
protect your hands.
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. Do not wear
shorts, sandals or go
barefoot.
5FS 310
English / USA
Avoid loose- fitting jackets,
scarfs, neckties, jewelry,
flared or cuffed pants,
unconfined long hair or
anything that could
become caught on
branches, brush or the moving parts of
the unit. Secure hair so it is above
shoulder level.
Good footing is very
important. Wear sturdy
boots with nonslip soles.
Steel-toed safety boots
are recommended.
Wear an approved safety
hard hat to reduce the risk
of injury to your head
when there is a danger of
head injuries.
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
and 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. For the
cutting attachments authorized by
STIHL for your unit, see the chapter
“Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness“ in the instruction manual or the
STIHL “Power Tools and Accessories“
catalog.
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 loss of
control and blade or line contact, never
carry or transport your power tool with
the cutting attachment moving.
389BA019 KN
It may be carried only in a horizontal
position. Grip the shaft in a manner that
the machine is balanced horizontally.
Keep the hot muffler away from your
body and the cutting attachment behind
you.
6
FS 310
English / USA
!Warning!
Always shut off the engine and make
sure the cutting attachment has stopped
before putting a trimmer/brushcutter
down. When transporting it in a vehicle,
properly secure it to prevent turnover,
fuel spillage and damage to the unit.
STIHL recommends that you keep metal
blades covered with the transport guard
(optional accessory).
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, 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 neck,
the cap is not properly seated and
tightened and you must repeat the
above steps.
7FS 310
English / USA
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.
Before Starting
!Warning!
Always check your power tool for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger interlock, stop switch, cutting
attachment, deflector and harness. The
throttle trigger must move freely and
always spring back to the idle position.
Never attempt to modify the controls or
safety devices. Never use a power tool
that is damaged or not properly
maintained.
!Warning!
The cutting attachment must be properly
tightened and in safe operating
condition. Inspect for loose parts (nuts,
screws, etc.) and for cracked or
damaged heads or cracked, bent,
warped or damaged blades. Replace
damaged heads or blades before using
the power tool. Always keep blades
sharp.
Keep the handles clean and dry at all
times; it is particularly important to keep
them free of moisture, pitch, oil, grease
or resin in order for you to maintain a firm
grip and properly control your power
tool.
!Warning!
Check that the spark plug boot is
securely mounted on the spark plug – a
loose boot may cause arcing that could
ignite combustible fumes and cause a
fire.
! Warning!
To reduce the risk
of personal injury
to the operator
from blade or line
contact and
thrown objects, make sure your unit is
equipped with the proper deflector,
handle and harness for the type of
cutting attachment being used (see
chart in the chapter on "Approved
Combinations of Cutting Attachment,
Deflector, Handle and Harness").
As can be seen in that chart, some
cutting attachments may require you to
change your deflector, handle and/or
harness.
Keep the deflector (and the attached
skirt where appropriate) adjusted
properly at all times (see chapters on
"Mounting the Deflector" and "Mounting
the Cutting Attachments" of your
instruction manual).
!Warning!
Do not attach any cutting attachment to
a unit without proper installation of all
required parts. Failure to use the proper
parts may cause the blade or head to fly
off and seriously injure the operator or
bystanders.
8
FS 310
English / USA
.
A
B
Arrows on the deflector (A) and limit stop
(B) (as seen from the underside) show
the correct direction of rotation of the
cutting attachment. When viewed from
above, however, the cutting attachment
rotates counterclockwise.
Adjust carrying harness and hand grip to
suit your size before starting work. The
machine should be properly balanced as
specified in your instruction manual for
proper control and less fatigue in
operation. To be better prepared in case
of an emergency, practice releasing the
unit from the harness as quickly as
possible.
Starting
Start the engine at least 10 feet
(3 meters) from the fueling spot,
outdoors only.
For specific starting instructions, see the
appropriate section of your manual.
Place the power tool on firm ground or
000BA006 KN
other solid surface in an open area.
Maintain good balance and secure
footing.
!Warning!
To reduce the risk of injury from blade or
line contact, be absolutely sure that the
cutting attachment is clear of you and all
other obstructions and objects, including
the ground, because when the engine
000BA007 KN
starts at starting-throttle, engine speed
will be fast enough for the clutch to
engage and move the cutting
attachment.
Once the engine has started,
immediately blip the throttle trigger,
which should release the starting throttle
and allow the engine to slow down to
idle.
With the engine running only at idle,
attach the power tool to the spring hook
of your harness (see appropriate
chapter of this manual).
!Warning!
Your power tool is a one-person
machine. Do not allow other persons in
the general work area, even when
starting.
!Warning!
To reduce the risk of injury from loss of
control, do not attempt to “drop start”
your power tool.
!Warning!
When you pull the starter grip, do not
wrap the starter rope around your hand.
Do not let the grip snap back, but guide
the starter rope to rewind it properly.
Failure to follow this procedure may
result in injury to your hand or fingers
and may damage the starter
mechanism.
Important Adjustments
!Warning!
To reduce the risk of personal injury from
loss of control or contact with the
running cutting attachment, do not use
your unit with incorrect idle adjustment.
At correct idle speed, the cutting
attachment 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.
9FS 310
English / USA
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.
!Warning!
Never attempt to operate
your power tool with one
hand. Loss of control of
the power tool resulting in
serious or fatal injury may
result. To reduce the risk
of cut injuries, keep hands and feet away
from the cutting attachment. Never
touch a moving cutting attachment with
your hand or any other part of your body.
002BA055 KN
!Warning!
Do not overreach. 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 and ditches to
avoid stumbling. For better footing, clear
002BA054 KN
away scrub and cuttings. Be extremely
cautious when working on slopes or
uneven ground.
!Warning
To reduce the risk of injury from loss of
control, never work on a ladder or on any
other insecure support. Never hold the
cutting attachment above waist height.
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!
As soon as the engine is
running, this product
generates toxic exhaust
fumes containing
chemicals such as
unburned hydrocarbons
(including benzene) and carbon
monoxide that are known to cause
respiratory problems, cancer, birth
defects, or other reproductive harm.
Some of the gases (e.g. carbon
monoxide) may be colorless and
odorless. To reduce the risk of serious or
fatal injury/illness from inhaling toxic
fumes, never run the machine indoors or
in poorly ventilated locations.
!Warning!
If the vegetation being cut or the
surrounding ground is coated with a
chemical substance (such as an active
pesticide or herbicide), read and follow
the instructions and warnings that
accompanied the substance at issue.
10
FS 310
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. Control dust at the source
where possible. Use good work
practices, such as 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.
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, shut off
the engine immediately – move the slide
control / stop switch to 0 or STOP.
!Warning!
The cutting attachment
continues to rotate for a
short period after the
throttle trigger is released
(flywheel effect).
15m (50ft)
The rotating cutting attachment may
fling foreign objects directly or by
ricochet a great distance.
To reduce the risk of eye and other injury
always wear proper eye protection (see
the chapter on “Proper Clothing“) and
ensure that bystanders are at least 50
feet (15 m) away. To reduce the risk of
damage to property, also maintain this
distance from such objects as vehicles
or windows. Any coworkers who must be
in the restricted area should also wear
goggles or protective glasses. Stop the
engine immediately if you are
approached.
!Warning!
Before you start work,
examine the area for
stones, glass, fence wire,
metal, trash or other solid
objects. The cutting
attachment could throw
objects of this kind.
!Warning!
This trimmer/brushcutter is normally to
be used at ground level with the cutting
attachment parallel to the ground. Use of
a trimmer/brushcutter above ground
level or with the cutting attachment
perpendicular to the ground may
increase the risk of injury, since the
cutting attachment is more fully exposed
and the power tool may be more difficult
to control.
!Warning!
During cutting, check the tightness and
the condition of the cutting attachment at
regular short intervals with the engine
and attachment stopped. If the behavior
of the attachment changes during use,
stop the engine immediately, wait until
the cutting attachment stops, and check
the nut securing the attachment for
tightness and the blade or head for
cracks, wear and damage.
11FS 310
English / USA
!Warning!
A loose blade or head may vibrate,
crack, break or come off the trimmer/
brushcutter, which may result in serious
or fatal injury. Make sure that the cutting
attachment is properly tightened. Use
the wrench supplied or one of sufficient
length to obtain the proper torque. If the
blade or head loosens after being
properly tightened, stop work
immediately. The retaining nut may be
worn or damaged and should be
replaced. If the blade or head continues
to loosen, see your STIHL dealer. Never
use a trimmer/brushcutter with a loose
cutting attachment.
!Warning!
Replace a cracked, or damaged or
worn-out head or a cracked, bent,
warped, damaged, dull or worn out
blade immediately, even if damage is
limited to superficial cracks. Such
attachments may shatter at high speed
and cause serious or fatal injury.
!Warning!
When using rigid blades, avoid cutting
close to fences, sides of buildings, tree
trunks, stones or other such objects that
could cause the power tool to kick out or
could cause damage to the blade.
STIHL recommends use of the nylon line
heads for such jobs. In addition, be alert
to an increased possibility of ricochets in
such situations.
!Warning!
If the head, blade or deflector becomes
clogged or stuck, always shut off the
engine and make sure the cutting
attachment has stopped before
cleaning. Grass, weeds, etc. should be
cleaned off the blade or from around the
head at regular intervals.
!Warning!
To reduce the risk of unintentional
rotation of the cutting attachment and
injury, always shut off the engine and
remove the spark plug boot before
replacing the cutting attachment. To
reduce the risk of injury, always shut off
the engine before adjusting the length of
the nylon line on manually adjustable
mowing heads.
!Warning
The gearbox becomes hot during
operation. To reduce the risk of burn
injury, do not touch the gear housing
when it is hot.
!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 away from any combustible
substances.
!Warning!
Never modify your muffler. The muffler
could be damaged and 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.
12
FS 310
English / USA
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
cylinder housing 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 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.
USING THE CUTTING
ATTACHMENTS
For an illustration of the various cutting
attachments and instructions on proper
mounting see the chapter on "Mounting
the Cutting Attachments" in your
instruction manual.
Using the Mowing Heads
Do not use with mowing line longer than
the intended length. With a properly
mounted deflector, the built-in linelimiting blade will automatically adjust
the line to its proper length.
Using the unit with an overly long nylon
cutting line increases the load on the
engine and reduces its operating speed.
This causes the clutch to slip
continuously and results in overheating
and damage to important components
(e.g. clutch, polymer housing
components). Such damage could,
among other things, cause the cutting
attachment to rotate at idle.
13FS 310
English / USA
Mowing heads are to be used only on
trimmer/brushcutters equipped with a
line-limiting blade in the deflector in
order to keep the line at the proper
length (see "Parts and Controls" chapter
in your instruction manual).
If the lawn edges are planted with trees
or bordered by a fence etc., it is best to
use a nylon line head. It achieves a
"softer" cut with less risk of damaging
tree bark etc. than polymer blades.
However, the polymer-bladed STIHL
PolyCut produces a better cut if there
are no plants along the edge of the lawn.
Sharpening is not necessary, and worn
polymer blades are easily replaced.
!Warning!
To reduce the risk of serious injury,
never use wire or metal-reinforced line
or other material in place of the nylon
cutting lines. Pieces of wire could break
off and be thrown at high speed toward
the operator or bystanders.
STIHL SuperCut mowing head
Fresh line is advanced automatically.
Frayed line is replaced by a simple
adjustment (see instruction sheet
000BA015 KN
supplied with mowing head).
STIHL TrimCut mowing head
Frayed line is replaced by a simple
adjustment (see instruction sheet
supplied with mowing head).
STIHL AUTOCUT mowing head
Nylon cutting cord advances
automatically when tapped against the
ground (TapAction).
STIHL PolyCut mowing head
002BA177 KN
Uses either nylon lines or nonrigid,
pivoting polymer blades.
!Warning!
Three rectangular wear limit marks are
applied to the base (periphery) of the
PolyCut. To reduce the risk of serious
injury from breakage of the head or
blades, the PolyCut must not be used
when it has worn as far as one of these
marks. It is important to follow the
maintenance instructions supplied with
the head.
14
FS 310
English / USA
Risk of Kickout (Blade Thrust)
with All Rigid Cutting Blades
!Warning!
Kickout (blade thrust) is the sudden and
uncontrolled motion towards the
operator's right or rear that can occur
when the shaded area of a rotating
blade comes in contact with a solid rigid
object like a tree, rock, bush or wall. The
rapid counterclockwise rotation of the
blade may be stopped or slowed, and
the cutting attachment may be thrown to
the right or to the rear.
This kickout (blade thrust) may cause
loss of control of the power tool and may
result in serious or fatal injury to the
operator or bystanders. To reduce the
risk of injury, extreme caution should be
used when cutting with the shaded area
of any rigid blade.
Using the Grass Cutting Blade
002BA135 KN
All kinds of grass and weeds can be
easily cut with the grass cutting blade.
The power tool is swept in an arc similar
to a scythe.
!Warning!
To reduce the risk of serious or fatal
injury from blade breakage, never
attempt to use this blade to cut woody
materials.
The 4-tooth grass cutting blade is
intended to cut grass and weeds. It has
4 cutting knives with cutting edges on
both sides, i.e. front and rear. When the
cutting edges on one side become dull,
the blade can be turned over to utilize
the cutting edges on the other side.
The 8-tooth grass cutting blade is
recommended for cutting fern or reed.
Both types of grass cutting blade have to
be resharpened when all cutting edges
are dull.
Using the Brush Knife
When fitted to the power tool, the brush
knife is suitable for applications ranging
from cutting matted grass to clearing
weeds, wild growth and scrub.
000BA020 KN
002BA066 KN
To cut wild growth and scrub, lower the
rotating brush knife down onto the
growth to achieve a chopping effect –
but keep the tool below waist height at
all times.
Exercise extreme caution when using
this method of cutting. The higher the
cutting attachment is off the ground, the
greater the risk of loss of control and of
cuttings being thrown sideways.
15FS 310
English / USA
Use the power tool like a scythe to cut
grass, i.e. sweep it to and fro in an arc.
!Warning!
When cutting woody materials, use the
left side of the blade to avoid "kickout"
(blade thrust) situations.
!Warning!
Improper use of a brush knife may cause
it to crack, chip or shatter. Thrown blade
fragments may seriously or fatally injure
the operator or bystanders. To reduce
the risk of injury, avoid contact with hard
or solid foreign objects such as stones,
rocks or pieces of metal.
!Warning!
When cutting young saplings or other
woody materials up to 2 cm (3/4") in
diameter, use the left side of the blade to
avoid "kickout" situations (see section
on “Risk of kickout (blade thrust) with all
rigid cutting blades”). Do not attempt to
cut woody material with a larger
diameter, since the blade may catch or
jerk the power tool forward. This may
cause damage to the blade or power tool
or loss of control of the power tool,
resulting in personal injury. Use a
circular saw blade for such work.
!Warning!
Inspect the brush knife at regular short
intervals for signs of damage. Do not
continue working with a damaged brush
knife. Resharpen the brush knife
regularly (when it has dulled noticeably).
Using the Circular Saw Blade
Circular saw blades are suitable for
thinning brush and cutting small trees up
to a diameter of 4 cm (1 1/2”). Do not
attempt to cut trees with larger
diameters, since the blade may catch or
jerk the trimmer/brushcutter forward.
This may cause damage to the blade or
loss of control of the power tool and
result in serious injury. Use a chain saw
for such work.
!Warning!
To reduce the risk that the blade will
crack and/or break, avoid all contact with
stones, rocks or the ground. Sharpen
blades in a timely manner as specified –
dull teeth may cause the blade to crack
or shatter.
When a trimmer/brushcutter with a
circular saw blade is used to cut down
small trees, STIHL recommends that the
standard deflector be removed and
replaced by the special limit stop
deflector (see chapter on “Mounting the
Deflector”). This limit stop helps to keep
the unit positioned against the tree
during the cutting process.
Inexperienced users should place the
left side of the stop against the tree trunk
000BA016 KN
before beginning to cut. This will keep
the trimmer/brushcutter against the tree
during the cutting operation and will
reduce the risk of loss of control and
possible kickout (described above and
briefly again below).
16
FS 310
English / USA
Before starting the cut, accelerate the
engine up to full throttle. Perform cut
with uniform pressure. STIHL
recommends that the circular saw blade
be applied to the right of the tree, using
the non-shaded area of the blade, as
shown in the illustration above.
!Warning!
The risk of kickout is highest when
cutting in the darker shaded area. To
reduce the risk of kickout and resulting
injury, do not use this area of the circular
saw blade for cutting trees or shrubs.
Special techniques using the lighter
002BA214 ST
shaded areas of the blade to cut shrubs
and trees should only be used by
experienced operators with specialized
training in the use and control of the
trimmer/brushcutter.
!Warning!
To reduce the risk of loss of control and
serious injury to the operator or
bystanders by a kickout, never use a
circular saw blade on a trimmer/
brushcutter with a loop handle, but
rather only on one with a bicycle handle.
When felling small trees, maintain a
distance of at least two tree lengths from
the nearest coworker.
!Warning!
In order to reduce the risk of injury from
002BA068 KN
thrown objects or operator contact with
the blade or head, be sure to remount
the standard deflector when no longer
using a circular saw blade.
MAINTENANCE, REPAIR AND
STORING
Maintenance, replacement, or repair
of the emission control devices and
systems may be performed by any
nonroad engine repair establishment
or individual. However, if you make a
warranty claim for a component
which has not been serviced or
maintained properly or if
nonapproved replacement parts were
used, STIHL may deny coverage.
!Warning!
Use only identical STIHL replacement
parts for maintenance and repair. Use of
non-STIHL parts may cause serious or
fatal injury.
Strictly follow the maintenance and
repair instructions in the appropriate
sections of your instruction manual.
!Warning!
Always stop the engine and make sure
that the cutting attachment is stopped
before doing any maintenance or repair
work or cleaning the power tool. Do not
attempt any maintenance or repair work
not described in your instruction manual.
Have such work performed by your
STIHL servicing dealer only.
Wear gloves when handling or
performing maintenance on blades.
17FS 310
English / USA
!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 attached.) A loose
connection between the spark plug 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 power tool 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 power tool if
the screen is missing or damaged.
Remember that the risk of forest fires is
greater in hot or dry weather.
!Warning!
Never repair damaged cutting attachments by welding, straightening or
modifying the shape. This may cause
parts of the cutting attachment to come
off and result in serious or fatal injuries.
Keep blades sharp. Tighten all nuts,
bolts and screws, except the carburetor
adjustment screws, after each use.
Store the power tool in a dry and high or
locked location out of reach of children.
Before storing for longer than a few
days, always empty the fuel tank. See
chapter "Storing the Machine" in the
instruction manual.
18
FS 310
Approved Combinations of Cutting Tool, Deflector, Stop
and Harness
English / USA
Cutting Tools
Mowing heads
1 STIHL SuperCut 40-2
2 STIHL AutoCut 40-2
3 STIHL TrimCut 40-2
4 STIHL TrimCut 41-2
5 STIHL PolyCut 40-3
Metal mowing tools
6 Grass cutting blade 230-4
7 Grass cutting blade 255-8
8 Brush knife 300-3
Circular saw blades
9 Chisel tooth
circular saw blade 200
10 Scratcher tooth
circular saw blade 200
Deflectors
11 Deflector for mowing heads 1 to 4
12 Deflector with skirt and blade
for mowing heads 1 to 4
13 Defector without skirt and blade for
mowing tools 5 to 7
Limit Stop
14 Limit stop for circular saw
blades 200
Harnesses
15 Full harness
16 Deluxe full harness
Equipment
Among other parts, the complete unit
includes:
– Cutting tool
– Deflector or limit stop
– Bike handle
–Harness
Approved Combinations
Select correct combination from the
table on the next page on basis of the
cutting tool.
For safety reasons only the tools,
deflectors, handles and harnesses
shown in each row of the table may
be used together.
No other combinations are
permitted because of the risk of
accidents.
To reduce the risk of personal injury, take
special care to avoid contact with the
rotating cutting tool.
19FS 310
English / USA
0
0
Cutting Tools Deflectors, Limit Stop Harnesses
11
1
2
681FK037 KN
681FK007
681BA004 KN
5
681FK012
12
681BA003 KN
15
02BA006 K
681FK001
3, 4
13
6
9
7
10
681FK018
681FK014
8
681FK015
681BA005 KN
14
16
681FK016
681BA007 KN
02BA026 KN
20
FS 310
Mounting the Bike Handle
2
English / USA
3
1
: Hold the lower clamp (1) steady.
: Unscrew and remove the clamp
screw (2).
: Remove the upper clamp (3) from
the lower clamp.
Upper and lower clamps are loose
once the clamp screw has been
removed.
A
4
1
256BA001 KN
: Place the handlebar (4) in the lower
clamp (1) so that distance A is no
more than 15 cm (6 in).
: Place upper clamp in position and
press it down.
: Fit the clamp screw.
: Line up handlebar at right angles to
the drive tube.
: Tighten down the clamp screw.
6
5
7
256BA002 KN
: Loosen the screw (5)
: Push the control handle (6) – throttle
trigger must face gearhead – onto
the handlebar (7) so that the holes
(8) line up.
: Insert screw and tighten it down
firmly.
: Go to "Adjusting the Throttle Cable
To save space when transporting or
storing the machine, loosen the
clamp screw and swing the
handlebar in line with the shaft, fold
the handles down.
6
8
8
256BA081 KN
21FS 310
English / USA
Adjusting the Throttle Cable
A properly adjusted throttle cable is
the precondition for correct
operation in the full throttle, starting
throttle and idle positions.
Adjust the throttle cable only after
the unit is fully assembled – the
control handle must be in the normal
operating position.
: Use a suitable tool to push the slide
to the bottom of the slot (see
illustration).
STOP
2
1
249BA017 KN
: Press down the trigger interlock (1)
and squeeze the throttle trigger (2)
(full throttle) – this sets the throttle
cable correctly.
002BA163 KN
22
FS 310
Mounting the Deflectors
and Limit Stop
English / USA
1
3
2
3
Deflectors
1 = Deflector for mowing tools
2 = Deflector for mowing heads
Mounting the Deflector
: Place the deflector in position.
: Fit the plate (3).
: Insert the screws and tighten them
down firmly.
4
256BA085 KN
Limit Stop
4 = Limit stop for circular saw blades.
Mounting the Limit Stop
: Place the stop in position.
: Insert the screws and tighten them
down firmly.
8
5
6
256BA086 KN
1
7
If you use one of the mowing heads,
note that the skirt (5) must be fitted onto
the deflector (1):
All nylon line mowing heads:
: Use the lower guide slot (6) and, in
addition, push the blade (7) into the
upper guide slot on the skirt – line it
up with the first hole.
: Insert the screw and tighten it down
firmly.
PolyCut 40-3 mowing head:
: Slide the skirt (8) into the upper
guide slot.
256BA087 KN
23FS 310
English / USA
Mounting the Cutting Tools
3
8
4
5
6
2
1
Blocking the Drive Shaft
: Insert the stop pin (1) in the bore (2)
in the gearhead as far as stop, apply
slight pressure.
: Rotate the output shaft until the stop
pin slips into position.
: Use combination wrench (3) to
loosen and unscrew the nut (4)
clockwise.
: Remove the rider plate (5) and
thrust washer (6).
9
10
256BA006 KN
The guard ring (7) for mowing
applications and guard washer (8)
should be fitted to ensure optimum
protection from grass cuttings when
using mowing tools.
Before mounting a circular saw blade:
: Remove the guard washer (8) and
pull off the thrust plate (9).
: Remove the guard ring (7) for
mowing applications.
: Fit the guard ring (10) for saw
blades and the thrust plate.
7
11
256BA007 KN
STIHL SuperCut Mowing Head
STIHL AutoCut Mowing Head
STIHL TrimCut Mowing Head
: Block the output shaft with the stop
pin.
: Screw cutting head counter-
clockwise onto the output shaft (11)
and tighten it down firmly
Remove the stop pin.
Removing the mowing head
: Block the output shaft.
: Unscrew the mowing head
clockwise.
256BA000 KN
24
FS 310
English / USA
4
6
STIHL PolyCut 40-3 Mowing Head
: Block the output shaft with the stop
pin.
: Position the mowing head on the
shaft.
: Fit the thrust washer (6) – convex
side must face down.
: Screw on the nut (4) counter-
clockwise and tighten it down
firmly.
Remove the stop pin.
Adjusting Nylon Line
Note:
A detailed description is contained in the
instruction sheet supplied with the
mowing head.
SuperCut mowing head
Fresh line is advanced automatically
during mowing work and trimmed to the
correct length by the blade on the
deflector.
Line feed operates only if both lines are
still at least 2.4 in (6 cm) long.
AutoCut mowing head
Hold unit with engine running (mowing
head must rotate) above the lawn.
: Tap the mowing head on the ground
256BA010 KN
– fresh line is advanced and the
blade on the deflector trims surplus
line to the correct length.
Line feed operates only if both lines are
still at least 1 in (2.5 cm) long.
TrimCut mowing head
Shut off the engine and move the slide
control to 0. Hold mowing head housing
firmly and
: Pull spool up – rotate it about 1/6
turn counterclockwise and allow it to
spring back.
: Pull ends of lines outward.
Repeat the above procedure as
necessary until both lines are 5.5 in
(14 cm) long.
Rotating the spool from one stop to the
next advances about 1.6 in (4 cm) of
fresh line.
Removing the mowing head
: Block the output shaft.
: Unscrew the nut clockwise.
If the mounting nut is too loose,
fit a new one.
25FS 310
English / USA
2
: Fit rider plate (5) for sawing.
4
3
1
2
4
5
1
: Block the output shaft.
: Screw on nut (4) counterclockwise
and tighten it down firmly.
Removing the cutting tool
: Block the output shaft.
: Unscrew the nut clockwise.
If the mounting nut is too loose,
fit a new one.
256BA068 KN
Grass Cutting Blades,
Brush Knife
: Place the cutting tool (1) in position.
Collar (see arrow) must engage the
cutting tool’s mounting hole.
Grass cutting blade 255-8:
Cutting edges must point
clockwise.
: Fit thrust washer (2) – convex side
must face up.
: Fit rider plate (3) for mowing.
: Block the output shaft.
: Screw on nut (4) counterclockwise
and tighten it down firmly.
26
Removing the cutting tool
: Block the output shaft.
: Unscrew the nut clockwise.
If the mounting nut is too loose,
fit a new one.
Circular Saw Blades 200 and 225
: Place the cutting tool (1) in position.
Collar (see arrow) must engage the
cutting tool’s mounting hole.
Cutting edges must point
clockwise.
: Fit thrust washer (2) – convex side
must face up.
FS 310
4-MIX Engine Fuel
English / USA
The STIHL 4-MIX engine features gas
oil lubrication and must be run on a fuel
mixture of gasoline and engine oil.
It operates otherwise on the 4-stroke
principle.
This engine is certified to operate on
unleaded gasoline and the STIHL twostroke engine oil at a mix ratio of 50:1.
Your engine requires a mixture of highquality gasoline and quality two-stroke
air cooled engine oil.
Use mid-grade unleaded gasoline with a
minimum octane rating of 89 (R+M/2). If
the octane rating of the mid-grade
gasoline in your area is lower, use
premium unleaded fuel.
Fuel with a lower octane rating may
increase engine temperatures. This, in
turn, increases the risk of piston seizure
and damage to the engine.
The chemical composition of the fuel is
also important. Some fuel additives not
only detrimentally affect elastomers
(carburetor diaphragms, oil seals, fuel
lines, etc.), but magnesium castings and
catalytic converters as well. This could
cause running problems or even
damage the engine. For this reason
STIHL recommends that you use only
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.
27FS 310
English / USA
Fueling
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
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.
Oil (STIHL 50:1 or
equivalent high-quality oils)
Before fueling, clean the filler cap and
the area around it to ensure that no dirt
falls into the tank.
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
: Raise the grip until it is upright.
: Turn the cap counterclockwise
(approx. a quarter turn).
: Remove the filler cap.
28
FS 310
English / USA
Closing the cap
: Fit the cap – grip upright –marks
must line up.
: Turn the cap clockwise as far as
stop (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 engage the recess
in the filler neck, the cap is not
properly seated and tightened and
you must repeat the above steps.
Fitting the Harness
1
2
3
: Put on the full harness (1).
: Adjust length until the spring hook
(2) is about a hand’s width below
your right hip. Over-long straps can
be cut to length after making the
adjustments.
: Attach the spring hook to the
machine’s perforated strip (3).
Find the right attachment point for the
cutting tool you are using – see section
"Balancing the Machine".
Balancing the Machine
002BA240 KN
: Attach machine to the harness. Let
it go and check to see how it is
balanced – change the attachment
point of the spring hook as
necessary:
Mowing tools (mowing heads,
grass cutting blades, brush knives,
Shredder blades) should just touch
the ground (top illustration).
Circular saw blades should
"hover" about 20 cm (8 in) above
the ground (bottom illustration).
256BA016 KN
256BA017 KN
29FS 310
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