STIHL FS 75 Owner's Manual

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Instruction Manual
Manual de instrucciones
Warning!
For safe operation follow all safety
precautions in Instruction Manual - improper
use can cause serious injury.
Advertencia!
Para su seguridad durante el manejo de este
seguridad dadas en el manual de
instrucciones - el uso indebido puede causar
lesiones graves.
STIH)
STIHL FS 75
1FS 75
English / USA
BA_SE_068_007_01_04.fm Printed on chlorine-free paper.
Printing inks contain vegetable oils; paper can be recycled.
© ANDREAS STIHL AG & Co. KG, 2004
0458 392 3021. M3. A4. PM. Printed in USA
STIHl

Contents

Guide to Using this Manual .............. 2
Safety Precautions and
Working Techniques ......................... 3
Mounting the Loop Handle ............. 14
Fitting the Carrying Eye* ................ 15
Mounting the Deflector ................... 15
Mounting the Cutting Tools ............. 15
Fuel ................................................ 18
Fueling ............................................ 19
Fitting the Harness ......................... 20
Starting / Stopping the Engine ........ 20
Operating Instructions .................... 23
Cleaning the Air Filter ..................... 23
Motor Management ........................ 24
Adjusting the Carburetor ................ 24
Spark Arresting Screen*
in Muffler ......................................... 26
Checking the Spark Plug ................ 26
Replacing the Starter Rope
and Rewind Spring ......................... 27
Storing the Machine ........................ 30
Replacing Nylon Line ..................... 30
Maintenance Chart ......................... 32
Parts and Controls .......................... 33
Specifications ................................. 35
Special Accessories ....................... 36
Maintenance and Repairs ............... 36
STIHL Incorporated Federal
and California Emission Control
Warranty Statement ........................ 37
* see “Guide to Using this Manual”
Allow only persons who understand this
manual to operate your trimmer.
To receive maximum performance and
satisfaction from your STIHL trimmer, it
is important that you read and under-
stand the maintenance and safety
precautions, starting on page 3, before
using your trimmer.
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 is a high-speed
cutting tool some special safety pre-
cautions 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 improve-
ments are made from time to time. If the
operating characteristics or the appear-
ance of your trimmer differs from those
described in this manual, please contact
your STIHL dealer for information and
assistance.
2
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FS 75
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:
: Step or procedure without direct
reference to an illustration.
Description of step or procedure that
refers directly to the illustration and
contains 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.
Warning where there is a risk of
damaging the machine or individual
components.
Note or hint which is not essential
for using the machine, but may
improve the operator’s under-
standing 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 refers to
several models with different
features. Components that are not
installed in all models and related
applications are marked thus
*.
Such components are 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, we cannot be responsible for
changes, modifications or
improvements not covered in this
manual.

Guide to Using this Manual

3FS 75
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Warning!
Because a trimmer 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
owner's manual and the
safety instructions periodically.
Careless or improper use of any trimmer
may cause serious or fatal injury.
Have your STIHL dealer show you how
to operate your trimmer. Observe all
applicable local safety regulations,
standards and ordinances.
!Warning!
Do not lend or rent your trimmer without
the owner's manual. Be sure that any-
one using your trimmer understands the
information contained in this manual.
!Warning!
The use of any trimmer may be
hazardous. If the rotating cutting tool
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 tool. Thrown
objects or damaged cutting tools may
result in serious or fatal injury to the
operator or bystanders.
!Warning!
Minors should never be allowed to
use a trimmer. Bystanders, especially
children, and animals should not be
allowed in the area where a trimmer
is in use.
Never let the trimmer run unattended.
Most of these safety precautions and
warnings apply to the use of all STIHL
trimmers. Different models may have
different parts and controls. See the
appropriate section of your owner's
manual for a description of the controls
and function of the parts of your model
trimmer.
Safe use of a trimmer involves
1. the operator
2. the trimmer
3. the use of the trimmer.
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 judgement. Do not operate a
trimmer when you are fatigued.
Be alert - if you get tired while operating
your trimmer, take a break.
Tiredness may result in loss of control.
Working with any trimmer can be
strenuous. If you have any condition that
might be aggravated by strenuous work,
check with your doctor before operating
a trimmer.
Safety Precautions and
Working Techniques
4
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FS 75
!Warning!
Prolonged use of a trimmer (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 white-
finger disease are not known, but cold
weather, smoking and diseases or
physical conditions that affect blood
vessels and blood transport, as well as
high vibration levels and long periods of
exposure to vibration are mentioned as
factors in the development of whitefinger
disease. In order to reduce the risk of
whitefinger disease and carpal tunnel
syndrome, please note the following:
: Most STIHL power tools are
available with an anti-vibration
("AV") system designed to reduce
the transmission of vibrations
created by the engine 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.
: Keep the AV system well
maintained. A trimmer 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 pressures and
take frequent breaks.
All the above mentioned precautions do
not guarantee that you will not sustain
whitefinger disease or carpal tunnel
syndrome. Therefore continual and
regular users should monitor closely the
condition of their hands and fingers. If
any of the above symptoms appear,
seek medical advice immediately.
!Warning!
The ignition system of 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 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.
!Warning!
The deflector provided with your trimmer
may not protect the operator from all
foreign objects (gravel, glass, wire, etc.)
thrown by the rotating cutting tool.
Thrown objects may also ricochet and
strike the operator.
!Warning!
To reduce the risk of injury
to your eyes never
operate a trimmer unless
wearing goggles or
properly fitted safety
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 safety glasses.
5FS 75
English / USA
!Warning!
Trimmer 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.
Protect your hands with
gloves when handling the
trimmer and the cutting
tool. Heavy-duty, nonslip
gloves improve your grip
and protect your hands.
Clothing must be sturdy
and snug-fitting, but allow
complete freedom of
movement. Avoid loose-
fitting jackets, scarfs,
neckties, jewelry, flared or
cuffed pants, unconfined longhair or
anything that could become caught on
branches, brush or moving parts of the
unit. Wear long pants made of heavy
material to protect your legs. Do not
wear shorts, pants, sandals or go bare
foot. Secure hair so it is above shoulder
level.
Good footing is most
important in trimmer work.
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 TRIMMER
For illustrations and definitions of the
trimmer parts see the chapter on "Parts
and Controls".
!Warning!
Never modify a trimmer in any way. Only
attachments supplied by STIHL or
expressly approved by STIHL for use
with the specific STIHL trimmer models
are authorized. Although certain
unauthorized attachments are useable
for the STIHL trimmer, their use may, in
fact, be extremely dangerous.
!Warning!
To reduce the risk of injury to operator
from blade contact, metal blades may be
used on FS-trimmers equipped with a
bicycle, "J" handle or loop handle with
barrier bar and not on those FS- and
FE-models with a loop handle only.
Never use any
metal cutting
attachment on a
FS-model that has
a bent shaft.
6
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FS 75
THE USE OF THE TRIMMER
Transporting the trimmer
!Warning!
Always turn off the engine and make
sure the cutting attachment has stop-
ped before putting a trimmer down.
When transporting your trimmer in a
vehicle, properly secure it to prevent
turnover, fuel spillage and damage to the
trimmer.
Preparation for the use of the trimmer
Adjust hand grip according to
instructions in the owner's manual to suit
your size before starting work.
Always check your trimmer for proper
condition and operation before starting,
particularly the throttle trigger, throttle
trigger interlock (if applicable), stop
switch, cutting tool, and deflector.
Arrows on the deflector show the correct
direction of rotation of the cutting tool.
The throttle trigger must move freely
and always spring back to the idle
position. The cutting tool must be
properly tightened and in safe operating
condition. Inspect for loose parts (nuts,
screws, etc.).
Fueling
Your STIHL trimmer uses an oil-gasoline
mixture for fuel (see the chapter on
"Fuel" of your owner's 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 trimmer.
Fueling Instructions
!Warning!
Fuel your trimmer 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 gas tank depending
on the fuel used, the weather conditions,
and the venting system of the tank. In
order to reduce the risk of burns and
other personal injury from escaping gas
vapor and fumes, remove the fuel filler
cap on your trimmer carefully so as to
allow any pressure build-up in the tank
to release slowly. Never remove fuel
filler cap while engine is running.
234BA004KN
7FS 75
English / USA
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
trimmer and check for leakage.
!Warning!
Check for fuel leakage while refueling
and during operation. If fuel or oil
leakage is found, do not start or run the
engine until leak is fixed and spilled fuel
has been wiped away. Take care not to
get fuel on your clothing. If this happens,
change your clothing immediately.
Different models may 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.
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 with as much force as
possible.
Starting
!Warning!
Your trimmer is a one-person machine.
Once started, it may fling foreign objects
for a great distance.
To reduce the risk of eye and other injury
insure that bystanders are at least
50 feet (15 m) away. Bystanders should
be encouraged to wear eye protection.
Stop the engine and cutting tool
immediately if you are approached. Start
and operate your trimmer without
assistance. For specific starting
instructions, see the appropriate section
of your manual. Place the trimmer on
firm ground or other solid surface in an
open area. Maintain a good balance and
secure footing.
15m (50ft)
8
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FS 75
!Warning!
To reduce the risk of injury from loss
of control, be absolutely sure that the
cutting tool is clear of you and all other
obstructions and objects, including the
ground, because when the engine starts
at starting-throttle, engine speed will be
fast enough for the clutch to engage and
turn the cutting tool.
!Warning!
When you pull the starter grip, don't
wrap the starter rope around your hand.
Do not allow the grip to snap back, but
guide the starter rope to rewind it
properly. Failure to follow this procedure
may result in injury to hand or fingers
and may damage the starter
mechanism.
With the engine running but at idle,
attach the trimmer to the spring hook of
your harness (see appropriate chapter
of this manual).
Catalytic converter
!Warning!
Some STIHL trimmer
models are equipped with
a catalytic converter,
which is designed to
reduce the exhaust
emissions of the engine
by a chemical process in the muffler.
Due to this process, the muffler does not
cool down as rapidly as conventional
mufflers when the engine returns to idle
or is shut off. To reduce the risk of fire
and burn injuries, the following specific
safety precautions must be observed.
!Warning!
Since a muffler with a catalytic converter
cools down less rapidly than conven-
tional mufflers, always set your trimmer
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.
Let the engine cool down sitting on
concrete, metal, bare ground or solid
wood (e.g. the trunk of a felled tree)
away from any combustible substances.
!Warning!
To reduce the risk of fire or burn injury,
let the unit cool down before refueling
your trimmer after use.
!Warning!
Never disassemble or modify your
muffler. The muffler could be damaged
and cause an increase in heat radiation
or sparks, thereby increasing the risk of
fire or burn injury. You may also
permanently damage the engine. Have
your muffler serviced and repaired by
your STIHL Servicing Dealer only.
!Warning!
To reduce the risk of fire or burn injury,
keep the area around the muffler clean.
Remove all debris such as pine needles,
branches or leaves.
9FS 75
English / USA
!Warning!
An improperly mounted or damaged
cylinder housing or a damaged/
deformed muffler shell may interfere
with the cooling effect of the catalytic
converter. To reduce the risk of fire or
burn injury, do not continue work with a
damaged or improperly mounted
cylinder housing or a damaged/
deformed muffler shell. Your catalytic
converter is furnished with screens
designed to reduce the risk of fire from
the emission of hot particles. Due to the
heat from the catalytic reaction, these
screens will normally stay clean and
need no service or maintenance. If you
experience loss of performance and you
suspect a clogged screen, have your
muffler maintained by a STIHL Servicing
Dealer.
Working Conditions
Operate and start your trimmer only
outdoors in a ventilated area. Operate
the trimmer under good visibility and
daylight conditions only. Work carefully.
!Warning!
Your trimmer produces
toxic exhaust fumes as
soon as the engine is
running. These gases
(e.g. carbon monoxide)
may be colorless and
odorless. To reduce the risk of serious or
fatal injury from inhaling toxic fumes,
never run the trimmer indoors or in
poorly ventilated locations.
!Warning!
Use of this product can generate dust
and fumes containing chemicals known
to cause respiratory disease, cancer,
birth defects, or other reproductive
harm. If you are unfamiliar with the risks
associated with the particular dust or
fume at issue, consult your employer,
governmental agencies such as OSHA
and NIOSH, and other sources on
hazardous materials. California and
some other authorities, for instance,
have published lists of substances
known to cause cancer, reproductive
toxicity, etc. Control dust and fumes at
the source where possible. In this regard
use good work practices and follow the
recommendations of OSHA/NIOSH and
occupational and trade associations.
When the inhalation of toxic dust and
fumes cannot be eliminated, the
operator and any bystanders should
always wear a respirator approved by
NIOSH / MSHA for the type of dust and
/ or fumes encountered."
!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.
Do not cut any material other than
weed or similar soft vegetation.
The cutting tools may be used only
for the operations described in your
manual.
10
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FS 75
Always hold the trimmer firmly with both
hands. Wrap your fingers tightly around
the handles, keeping the handles
cradled between your thumb and fore-
finger. Keep your hands in this position
to have your trimmer under control at all
times. Make sure your trimmer handles
and grip are in good condition and free
of moisture, pitch, oil or grease.
!Warning!
Never attempt to operate any trimmer
with one hand. Loss of control of the
trimmer resulting in serious or fatal injury
may result.
!Warning!
To reduce the risk of bodily injury
resulting from loss of control and/or
contact with the cutting tool, make sure
your unit is equipped with the proper
handle and harness for the type of
cutting attachment being used.
!Warning!
To reduce the risk
of injury from
thrown objects and
blade contact,
never operate a
trimmer without a properly mounted
deflector. Keep the deflector (and the
skirt where appropriate) adjusted
properly at all times (see chapter on
mounting the various cutting tools of
your owner's manual). 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. Be extremely cautious
when working on slopes or uneven
ground.
Before cutting, inspect the
area for stones, glass,
pieces of metal, trash or
other solid objects. The
cutting attachment could
throw objects of this kind.
!Warning!
This trimmer is normally to be used at
ground level with the cutting attachment
parallel to the ground. Use of a trimmer
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 trimmer may be more difficult to
control. Never use your trimmer as a
hedge trimmer.
Do not operate using the starting
throttle lock as you do not have control
of the engine speed. See section of your
owner's manual on the proper use of the
slide control.
If the cutting tool or deflector becomes
clogged or stuck, always turn off the
engine and make sure the cutting tool
has stopped, before cleaning. Grass,
weeds, etc. should be cleaned off the
cutting tool at regular intervals.
002BA057 KN002BA056 KN
11FS 75
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!Warning!
During cutting, check the tightness and
the condition of the cutting tool at
regular intervals. If the behavior of the
tool changes, stop the engine im-
mediately, and check the nut securing
the tool for tightness and the cutting
tool for cracks and damage. Replace
damaged cutting tools immediately.
Such tools may shatter at high speed
and cause serious or fatal injury.
!Warning!
Keep hands and feet
away from cutting tool.
Never touch a rotating
cutting tool with your hand
or any part of your body. It
continues to rotate for a
short period after the throttle trigger is
released (flywheel effect).
Important adjustments
!Warning!
To reduce the risk of personal injury from
loss of control or contact with the
running cutting tool, do not use a cutting
tool 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 owner's manual.
If you cannot set the correct idle speed,
have your STIHL dealer check your
trimmer and make proper adjustments
and repairs.
MAINTENANCE, REPAIR AND
STORING
Maintenance, replacement, or repair
of the emission control devices and
systems may be performed by any
nonroad engine repair establishment
or individual. However if you claim
warranty for a component which has
not been serviced or maintained
properly or if non-approved replace-
ment parts were used, STIHL may
deny warranty.
!Warning!
Use only STIHL replacement parts for
maintenance and repair.
Use of non-STIHL parts may cause
serious or fatal injury.
Follow the maintenance and repair
instructions in the appropriate section of
your owner's manual. Please refer to the
maintenance chart on the last pages of
this manual.
!Warning!
Always stop the engine and make sure
that the cutting tool is stopped before
doing any maintenance or repair work
or cleaning the trimmer. Do not attempt
any maintenance or repair work not
described in your owner's manual.
Have such work performed at your
STIHL service shop only.
12
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FS 75
!Warning!
Never repair damaged cutting tools by
welding, straightening or modifying the
shape. This may cause parts of the
cutting tool to come off and result in
serious or fatal injuries.
!Warning!
Check condition of cutting tool at regular
short intervals. If behavior of tool
changes, check it immediately for
tightness or any signs of cracks in
particular. Replace damaged or dull
cutting tools immediately, even if they
have only superficial cracks. If the
tool loosens after being properly
tightened, the retaining nut may be
worn or damaged and should be
replaced. If the tool continues to loosen,
see your STIHL dealer.
!Warning!
To reduce the risk of fire and burn
injuries, check fuel filler cap for leaks at
regular intervals. Use the specified
spark plug and make sure it and the
ignition lead are always clean and in
good condition.
!Warning!
Never test the ignition system with
ignition wire terminal removed from
spark plug or with unseated spark plug,
since uncontained sparking may cause
a fire.
!Warning!
To reduce the risk of fire and burn injury,
use only spark plugs authorized by
STIHL. Always press spark plug boot
snugly onto spark plug terminal of the
proper size. (Note: If terminal has
detachable SAE adapter nut, it must be
attached.) A loose connection between
spark plug terminal and ignition wire
connector in the boot may create arcing
that could ignite combustible fumes and
cause a fire. Keep spark plug clean, and
make sure ignition lead is in good
condition.
!Warning!
Do not operate your trimmer if the
muffler is damaged, missing or modified.
An improperly maintained muffler will
increase the risk of fire and hearing loss.
Never touch a hot muffler or burn will
result. If your muffler was equipped with
a spark-arresting screen to reduce the
risk of fire, never operate your trimmer if
the screen is missing or damaged. Do
not modify or remove any part of the
muffler or spark arresting screen.
Remember that the risk of forest fires is
greater in hot or dry weather.
Tighten all nuts, bolts and screws,
except the carburetor adjustment
screws, after each use.
Additionally, the daily maintenance
schedule for your trimmer set forth in
your STIHL Owner's Manual should be
strictly followed.
For any maintenance please refer to the
maintenance chart and to the warranty
statement near the end of this manual.
Store trimmer in a dry, high or locked
location out of reach of children.
Before storing for longer than a few
days, always empty the fuel tank.
13FS 75
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USING THE CUTTING TOOLS
For an illustration of the various cutting
tools and instructions on proper mount-
ing see the chapter on "mounting the
cutting head" in your owner's manual.
Using the mowing heads
The STIHL AutoCut and PolyCut
mowing heads produce a clean and tidy
finish.
They are to be used only on trimmers
equipped with a limiter blade in the
deflector in order to keep the line at the
proper length (see "Parts and Controls"
chapter of this 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 with the 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
cutting 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 "AutoCut" mowing head
Nylon cutting cord advances auto-
matically when tapped against the
ground.
STIHL "PolyCut" mowing head
Uses either nylon lines or nonrigid
plastic blades
Important!
Three rectangular wear limit marks are
applied to the base (periphery) of the
Polycut 10-3. 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!
000BA019 KN
002BA177 KN
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FS 75
Check wear limit marks at regular
intervals.
Wear limit marks are incorporated in the
base of the PolyCut.
Stop using your PolyCut 5-3
immediately if one of the round holes
(1; arrow) becomes visible, or if the
upright rim (2; arrow) is worn as shown.
Install a new mowing head.
It is essential to observe the wear
limit marks since there is otherwise
a risk of the cutting tool shattering.
Thrown parts may result in personal
injury.
: Fit the loop handle (1) on the drive
tube, 5,9“ (15 cm) forward of the
control handle (2).
: Fit clamp (3) against drive tube and
slide it into the loop handle.
: Insert the square nut (4) in the loop
handle.
: Fit the clamp screw (5) from the
other side and tighten down firmly.
Adjusting loop handle to most
comfortable position
: Loosen the clamp screw (5).
: Slide the loop handle along the drive
tube as required.
: Retighten the clamp screw.
1
002BA073 KN
2
002BA074 KN

Mounting the Loop Handle

3
355BA030 KN
1
2
A
343BA023 KN
5
4
50 mm
( 2" )
15FS 75
English / USA
: For position of carrying eye see
"Parts and Controls"
: Place the clamp (1) with the
tapped hole on the left-hand side
of the drive tube.
: Squeeze the two ends of the clamp
together and hold in that position.
: Insert M 6 x 14 screw (2).
: Line up the carrying eye.
: Tighten down the screw firmly.
* see "Guide to Using this Manual"
: Slip the clamp (1) over the
deflector (2).
: Push deflector with clamp onto the
bearing housing (3) as far as stop.
: Tighten down the clamp.
Preparations
: Lay your trimmer on its back with
the shaft (2) facing up.
STIHL-“AutoCut 11-2“
: Take the thrust plate (1) off the
shaft (2).
STIHL-“PolyCut“
: Fit the thrust plate (1) on the shaft
(2) so that internal hexagon (3)
engages hexagon (4).

Fitting the Carrying Eye*

002BA142 KN
1
2
1

Mounting the Deflector

342BA045 KN
1
2
3
342BA002 KN

Mounting the Cutting Tools

342BA020 KN
1
2
3
4
16
English / USA
FS 75
Blocking the Drive Shaft
: Insert the stop pin (1) in the bores
(2) in the defelector and thrust plate.
Turn thrust plate to and fro until the
stop pin slips into position and
blocks the shaft.
Mounting the Mowing Head
Keep instruction sheet for cutting
head in a safe place.
Assembling STIHL AutoCut 11-2
: Fit spring (1) in the spool
housing (2).
: Wind the nylon lines onto the spool:
see "Replacing Nylon Line"
: Assemble the mowing head: see
"Replacing Nylon Line"
: Slip the mowing head (2) over the
shaft (3) and engage hexagon
recess (4) on external hexagon (5).
: Fit the cap (6) on the mowing head
and screw it clockwise onto shaft as
far as stop. Tighten it down firmly.
342BA021 KN
1
2
2
1
681BA014 KN
2
4
3
6
2
5
681BA015 KN
17FS 75
English / USA
STIHL PolyCut 10-3
: Screw the mowing head (7)
clockwise onto the shaft (3) as far
as stop.
: Use stop pin to block the shaft.
: Tighten down the mowing head
firmly.
Remove the stop pin.
STIHL PolyCut 5-3
: Place the nut (8) in the mowing
head.
: Screw the mowing head (7)
clockwise onto the shaft (3) as far
as stop.
: Use stop pin to block the shaft.
: Tighten down the mowing head
firmly.
Remove the stop pin.
Adjusting Nylon Line
STIHL AutoCut 11-2
: Hold the rotating mowing head
horizontal to the ground – tap it on
the ground – about 3 cm (1 1/4")
fresh line is advanced.
: The blade (1) on the deflector (2)
trims surplus line to the correct
length. Avoid tapping the head more
than once.
3
7
681BA016 KN
3
7
8
681BA017 KN
342BA024 KN
1
2
18
English / USA
FS 75
Line feed operates only if both lines
are at least 2.5cm (1") long.
STIHL PolyCut 10-3
Refer to instructions supplied with the
mowing head.
Removing the Mowing Head
: Block the shaft.
: Unscrew the mowing head
counterclockwise.
Replacing Cutting Line
AutoCut
See chapter "Replacing Nylon Line".
PolyCut 10-3
Refer to instructions supplied with the
mowing head.
Replacing Thermoplastic Blades
PolyCut
Follow the instructions supplied with the
mowing head.
This engine is certified to operate on
unleaded gasoline and the STIHL two-
stroke engine oil at a mix ratio of 50:1.
Your two-stroke engine requires a
mixture of high-quality gasoline and
quality two-stroke air cooled engine oil.
Use mid-grade unleaded gasoline with a
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 (two-
stroke water cooled) mix oils or other
mix oils that state they are for use in both
water cooled and air cooled engines
(e.g., outboard motors, snowmobiles,
chainsaws, mopeds, etc.).
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapor. When filling at
the pump, first remove the canister from
your vehicle and place the canister on
the ground before filling. Do not fill fuel
canisters that are sitting in or on a
vehicle.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The machine‘s fuel tank and the canister
in which fuel mix is stored should be
cleaned as necessary.

Fuel

19FS 75
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.
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 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.
After fueling, tighten fuel cap as
securely as possible by hand.
Change the fuel pick up body every
year.
Before storing your machine for a long
period, drain and clean the fuel tank and
run engine until carburetor is dry.
Gaso-
line
Oil (STIHL 50:1 or
equivalent high-quality oils)
US gal. US fl.oz
12.6
2 1/2 6.4
512.8

Fueling

389BA031 KN
389BA032 KN
20
English / USA
FS 75
Shoulder Strap*
: Put on the shoulder strap (1).
: With the brushcutter attached,
adjust length of strap until the spring
hook (2) is about a hand’s width
below your right hip.
* see "Guide to Using this Manual"
Controls
Throttle trigger interlock (1)
Throttle trigger (2)
Slide control (3)
Positions of Slide Control
STOP-O (4) – engine off – the ignition is
switched off
# – normal run position (5) – the engine
is running or can start
START (6) - the ignition is switched on,
the engine can start
Symbol on slide control
h (7) – stop symbol and arrow – to stop
the engine, push the slide control in
direction of the arrow on the stop symbol
(h ) to STOP-O.
Starting
: Hold down the throttle trigger
interlock and squeeze the throttle
trigger.
: While holding both levers in this
position, move the slide control to
START and hold it there.
: Now release the throttle trigger,
slide control and trigger interlock in
that order. This is the starting
throttle position.

Fitting the Harness

1
392BA039 KN
2
Starting / Stopping
the Engine
3
STOP
2
5
6
4
7
002BA181 KN
START
STOP-
1
21FS 75
English / USA
: Set the choke lever (8):
For cold start to g
For warm start to e
– also use this position if the engine
has been running but is still cold.
: Press fuel pump bulb (9) at least five
times even if bulb is filled with fuel.
: Put the unit on the ground:
It must rest securely on the engine
support and deflector.
Check that the cutting tool is not
touching the ground or any other
obstacles.
: Make sure you have a firm footing.
: Hold the unit with your left hand on
the control handle and press it down
firmly – your thumb should be
under the control handle.
Do not stand or kneel on the drive
tube! This could permanently
damage the drive tube.
: Pull the starter grip slowly with your
right hand until you feel it engage –
and then give it a brisk strong pull.
Do not pull out the starter rope all
the way – it might break.
: Do not let the starter grip snap
back – guide it slowly into the
housing so that the starter rope can
rewind properly.
: Continue cranking until the engine
runs.
When engine begins to fire:
: Move choke lever to e
: Continue cranking.
As soon as engine runs:
: Blip the throttle trigger –
the slide control moves to the run
position # – and the engine returns
to idling speed.
Make sure carburetor is correctly
adjusted – the cutting tool must not
rotate when the engine is idling.
Your power tool is ready for
operation.
393BA017 KN
8
8
393BA018 KN
9
355BA007 KN
22
English / USA
FS 75
To shut down the engine:
: Push the slide control in the
direction of the arrow (h ) to
STOP-O.
Other points to observe when
starting
At very low outside temperatures
As soon as engine runs:
: Blip the throttle trigger to disengage
the starting throttle position –
the slide control moves to the run
position # – and the engine settles
down to idle speed.
: Allow engine to warm up for a brief
period at part throttle.
If the engine does not start
If you did not move the choke lever to
e quickly enough after the engine
began to fire, the combustion chamber is
flooded.
: Move the choke lever to e
: Set the slide control, interlock lever
and throttle trigger to the starting
throttle position.
: Start the engine by pulling the
starter rope briskly – 10 to 20 pulls
may be necessary.
If the engine still does not start
: Push the slide control in the
direction of the arrow (h ) to
STOP-O.
: Pull off the spark plug boot (10).
: Unscrew and dry off the spark plug.
: Open the throttle wide.
: Crank the engine several times with
the starter to clear the combustion
chamber.
: Refit the spark plug.
: Connect the spark plug boot (press
it down firmly).
: Move the slide control to START.
: Set the choke lever to e – even if
engine is cold.
: Now start the engine.
Throttle cable adjustment
: Check adjustment of throttle cable
– see "Adjusting the Throttle Cable".
Fuel tank run until dry
: After refueling, press the fuel pump
bulb at least five times – even if bulb
is filled with fuel.
: Set the choke lever to suit the
engine temperature.
: Now start the engine.
393BA019 KN
10
23FS 75
English / USA
During break-in period
A factory new machine should not be run
at high revs (full throttle off load) for the
first three tank fillings. This avoids
unnecessary high loads during the
break-in period. As all moving parts
have to bed in during the break-in
period, the frictional resistances in the
engine are greater during this period.
The engine develops its maximum
power after about 5 to 15 tank fillings.
During operation
After a long period of full-throttle
operation, allow engine to run for a while
at idle speed so that the heat in the
engine can be dissipated by flow of
cooling air. This protects engine-
mounted components (ignition,
carburetor) from thermal overload.
After finishing work
Wait for engine to cool down. Drain the
fuel tank. Store the machine in a dry
place. Check tightness of nuts and
screws (not adjusting screws) at regular
intervals and retighten as necessary.
Dirty air filters reduce engine power
increase fuel consumption and make
starting more difficult.
If there is a noticeable loss of engine
power
: Move choke lever to g.
: Press in the tab (1).
: Ease the filter cover (2) over the tab
and take it away.
: Clean away loose dirt from around
the filter.
: Remove the foam and felt filter
elements.
: Wash the foam element in a clean,
non-flammable cleaning solution
(e.g. warm soapy water) and then
dry.
: Fit new felt element.
As a temporary measure you can
knock it out on the palm of your
hand or blow it out with compressed
air. Do not wash.
Replace damaged parts!
: Install the foam element (3) in the
filter cover (2).
: Place felt element (4) (lettering
facing inward) in filter housing (5).
: Fit filter cover so that it snaps into
position.

Operating Instructions Cleaning the Air Filter

355BA014 KN
2
1
2
3
355BA031 KN
4
5
355BA032 KN
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