Stihl FS 235 User manual

Contents
1 Introduction................................................. 2
2 Guide to Using this Manual.........................2
3 Overview..................................................... 3
4 Safety Precautions......................................4
5 Preparing Trimmer for Operation.............. 10
6 Assembling the Trimmer........................... 10
7 Adjusting Trimmer for User....................... 13
8 Mixing Fuel and Refueling the Brushcutter
.................................................................. 14
9 Starting and Stopping the Engine............. 15
10 Testing the Trimmer..................................16
11 Operating the Trimmer..............................17
12 After Finishing Work..................................18
13 Transporting..............................................18
14 Storing.......................................................18
15 Cleaning....................................................18
16 Maintenance............................................. 18
17 Repairing...................................................19
18 Troubleshooting........................................ 19
19 Specifications............................................21
20 Combinations of Cutting Attachments,
Deflectors and Carrying Systems............. 22
21 Spare Parts and Accessories....................22
22 Disposal.................................................... 22
23 EC Declaration of Conformity................... 23
1 Introduction
Dear Customer,
Thank you for choosing STIHL. We develop and
manufacture our quality products to meet our
customers’ requirements. The products are
designed for reliability even under extreme con‐
ditions.
STIHL also stands for premium service quality.
Our dealers guarantee competent advice and
instruction as well as comprehensive service
support.
STIHL expressly commit themselves to a sus‐
tainable and responsible handling of natural
resources. This user manual is intended to help
you use your STIHL product safely and in an
environmentally friendly manner over a long
service life.
We thank you for your confidence in us and hope
you will enjoy working with your STIHL product.
Dr. Nikolas Stihl
IMPORTANT! READ BEFORE USING AND
KEEP IN A SAFE PLACE FOR REFERENCE.
2 Guide to Using this Manual
2.1 Applicable Documentation
Local safety regulations apply.
► Read, understand and save the following
documents in addition to this instruction man‐
ual:
–Instruction manual and packaging of the
cutting attachment you are using
2.2 Symbols used with warnings in
the text
WARNING
■ This symbol indicates dangers that can cause
serious injuries or death.
► The measures indicated can avoid serious
injuries or death.
NOTICE
■ This symbol indicates dangers that can cause
damage to property.
► The measures indicated can avoid damage
to property.
2.3 Symbols in Text
This symbol refers to a chapter in this
instruction manual.
English
2 0458-507-0121-B
© ANDREAS STIHL AG & Co. KG 2022
0458-507-0121-B. VA1.B22.
Printed on chlorine-free paper
Printing inks contain vegetable oils, paper can be recycled.
Translation of Original Instruction Manual
0000008410_017_GB

3 Overview
3.1 Trimmer
25
23
22
21
11
10
8
9
6
5
17
16
15
13 18
20
19
1
2
3
4
7
#
12
24
14
14
0000-GXX-7804-A0
1 Filter Cover
Covers the air filter.
2 Air Filter
Filters the air entering the engine.
3 Choke Lever
Helps start the engine.
4 Manual Fuel Pump
Eases engine starts.
5 Spark Plug Boot
Connects ignition lead to spark plug
6 Spark Plug
Ignites fuel-air mixture in the engine.
7 Muffler
Reduces trimmer noise emissions.
8 Starter Grip
Serves to crank the engine.
9 Carburetor Adjusting Screws
For tuning the carburetor.
10 Fuel Tank Cap
Closes the fuel tank.
11 Handle
For holding and controlling the trimmer.
12 Throttle Cable
Connects the throttle trigger to the engine.
13 Shaft
Connects all components.
14 Throttle Cable Retainer
Secures throttle cable in position.
15 Slide Control
For starting, running and stopping the engine.
16 Throttle Trigger Lockout
Unlocks the throttle trigger.
17 Throttle Trigger
Controls engine speed.
18 Carrying Ring
For attaching carrying system.
19 Control Handle
For operating, holding and controlling the
trimmer.
20 Handlebar Clamp
Connects handlebar to the drive tube.
21 Handlebar
Connects control handle and left grip to drive
tube.
22 Gear Housing
Encloses the gearbox.
23 Opening for Stop Pin
Accommodates the stop pin.
24 Stop Pin
Blocks shaft while cutting attachment is being
mounted.
25 Screw Plug
Closes filler opening for STIHL gear grease.
# Rating Label with Serial Number
3.2 Deflectors and Cutting Attach‐
ments
The illustrations show examples of deflectors
and cutting attachments. Approved combinations
are listed in this instruction manual, 20.
6
8
0000-GXX-8194-A0
1
2
7
3
9
1
4
5
1 Universal deflector
Protects user from flying debris and contact
with the cutting attachment.
3 Overview English
0458-507-0121-B 3

2 Grass Cutting Blade
Cuts grass and weeds.
3 Brush Knife
Cuts brushwood.
4 Line Limiting Blade
Trims mowing line to correct length.
5 Skirt
Extends universal deflector for use with a
mowing head.
6 Mowing Head
The mowing head contains the mowing line.
7 Limit Stop
Protects user from flying debris and contact
with the circular saw blade and helps support
the trimmer against the wood during cutting
work.
8 Circular Saw Blade
Cuts shrubs and trees.
9 Transport Guard
Helps protect user from contact with metal
cutting attachments.
3.3 Symbols
Meanings of symbols that may be on the trimmer
and the deflector:
This symbol marks the fuel tank.
This symbol denotes the manual fuel
pump.
Engine is started with the slide control
lever in this position.
Engine is operated with the slide control in
this position.
Engine is stopped when the slide con‐
trol is in this position.
Slide control is moved in this direction to
stop the engine.
Engine is started with the choke lever in
this position.
Engine is made ready for start with the
choke lever in this position.
This symbol shows the direction of
rotation of the cutting attachment.
This symbol shows the maximum
diameter of the cutting attachment in
millimeters.
This symbol shows the rated speed of the
cutting attachment.
4 Safety Precautions
4.1 Warning Signs
4.1.1 Warning Symbols
Meanings of warning signs on the trimmer:
Observe safety notices and take the
necessary precautions.
Read, understand and save the
instruction manual.
Wear safety glasses, hearing protec‐
tion and a hard hat.
Wear safety boots.
Wear work gloves.
Observe safety notices on kickback
and take the necessary precautions.
Observe safety notices on flying debris
and take the necessary precautions.
15m (50ft)
Maintain safe distance.
Do not touch hot surface.
4.1.2 Universal Deflector and Skirt
Universal deflector
Meanings of warning signs on the universal
deflector:
Do not use this deflector without skirt
for mowing heads.
Use this deflector for grass cutting
blades.
Use use this deflector for brush knives.
English 4 Safety Precautions
4 0458-507-0121-B

Use this deflector for shredder blades.
Do not use this deflector for circular
saw blades.
Skirt
Meanings of warning signs on the skirt:
Use the universal deflector with skirt
and line limiting blade for mowing
heads.
4.2 Intended Use
The STIHL FS 235 brushcutter is designed for
the following applications:
–With a mowing head: Mowing grass
–with a grass cutting blade: Mowing grass and
weeds
–with a brush knife: Cutting brush with a stem
diameter up to 20 mm
–with a circular saw blade: Cutting shrubs and
trees with a stem diameter up to 40 mm
WARNING
■ Using the brushcutter for purposes other than
those it is designed for may result in serious or
fatal injuries and damage to property.
►Use the brushcutter as described in this
user manual.
4.3 The Operator
WARNING
■Users who have had no instruction cannot rec‐
ognize or assess the risks involved in using
the trimmer. The user or other persons may
sustain serious or fatal injuries.
► Read, understand and save the
instruction manual.
► If you pass the trimmer is on to another
user: Always give them the instruction man‐
ual.
►Make sure the user meets the following
requirements:
–The user must be rested.
–The user must be in good physical con‐
dition and mental health to operate and
work with the trimmer. If the user’s
physical, sensory or mental ability is
restricted, he or she may work only
under the supervision of or as instructed
by a responsible person.
–The user is able to recognize and
assess the risks involved in using the
trimmer.
–The user must be of legal age or is
being trained in a trade under supervi‐
sion in accordance with national rules
and regulations.
–The user has received instruction from a
STIHL servicing dealer or other experi‐
enced user before working with the trim‐
mer for the first time.
–The user must not be under the influ‐
ence of alcohol, medication or drugs.
► If you have any queries: Contact a STIHL
servicing dealer for assistance.
■ The trimmer’s ignition system produces an
electromagnetic field. This field may interfere
with some pacemakers. This can result in seri‐
ous or fatal injuries.
►If the user has a pacemaker: Make sure the
pacemaker is not affected.
4.4 Clothing and equipment
WARNING
■ Long hair can be drawn into the brushcutter
during operation. This may result in serious
injury to the user.
►Tie up and confine long hair above your
shoulders.
■ Objects can be thrown at high speed during
operation. This may result in injury to the user.
► Wear close-fitting safety glasses.
Suitable safety glasses are tested in
accordance with EN 166 or national
regulations and available commer‐
cially with the corresponding mark‐
ing.
►Wear face protection.
► Wear long trousers made from resistant
material.
■ Noise is generated during operation. Noise
can damage your hearing.
► Wear ear protection.
■ Falling objects can cause head injuries.
► If objects are likely to fall while work‐
ing: wear a hard hat.
■ Dust can be whipped up during operation.
Whipped up dust can damage the respiratory
passages and cause allergic reactions.
4 Safety Precautions English
0458-507-0121-B 5

► If dust is generated: Wear a dust respirator
mask.
■ Inappropriate clothing can snag on wood,
brush or the brushcutter. Users not wearing
suitable clothing are at risk of serious injury.
►Wear close-fitting clothing.
► Remove scarves and jewelry.
■ The user may come into contact with the rotat‐
ing cutting attachment during operation. This
may result in serious injury to the user.
►Wear robust footwear.
► If you are using a metal cutting
attachment: Wear steel-toed safety
boots.
► Wear long trousers made from resistant
material.
■ When mounting and dismounting the cutting
attachment and during cleaning or mainte‐
nance, the user may come into contact with
the sharp edges of the cutting attachment or
the crosscut blade. This may result in injury to
the user.
► Wear work gloves made from resist‐
ant material.
■ Wearing unsuitable footwear may cause the
user to slip. This may result in injury to the
user.
►Wear sturdy, closed-toed footwear with
high-grip soles.
4.5 Working Area and Surround‐
ings
WARNING
■Bystanders, children and animals are not
aware of the dangers of the brushcutter or fly‐
ing debris. This may result in serious injury to
bystanders, children and animals and damage
to property.
15m (50ft)
► Do not allow bystanders,
children or animals within 15
meters of the work area.
► Maintain a clearance of 15 meters from
objects.
► Do not leave the brushcutter unattended.
► Make sure that children cannot play with
the brushcutter.
■ Hot exhaust gas is emitted through the muffler
while the engine is running. Hot exhaust gas
can ignite easily flammable materials and
cause a fire.
►Keep exhaust gas well away from easily
flammable materials.
4.6 Safe Condition
4.6.1 Brushcutter
The brushcutter is in a safe condition if the fol‐
lowing points are observed:
–The brushcutter is not damaged.
–There is no fuel leaking from the trimmer.
–The fuel tank cap is closed.
–The brushcutter is clean.
–The controls function properly and have not
been modified.
–A combination of cutting attachment and
deflector recommended in this user manual is
mounted.
–The cutting attachment and deflector are prop‐
erly mounted.
–Genuine STIHL accessories for this brushcut‐
ter are fitted.
–The accessories are correctly attached.
–All accessible screws and fastening parts are
firmly tightened.
–Cutting attachment does not run while engine
is idling.
WARNING
■ If not in safe condition, components may no
longer operate correctly, safety devices may
be disabled and fuel leakage may occur.
There is a risk of serious or fatal injury.
►Work only with an undamaged brushcutter.
► If fuel is leaking from the trimmer: Do not
use the trimmer and contact a STIHL dealer
for assistance.
►Close the fuel tank cap.
► If the brushcutter is dirty: Clean the brush‐
cutter.
► Never attempt to modify your brushcutter.
Exception: Mounting one of the combina‐
tions of cutting attachment and deflector
recommended in this user manual.
►If the controls do not function properly: Do
not use your brushcutter.
► Fit genuine STIHL accessories for this
brushcutter.
► Mount the cutting attachment and deflector
as described in this user manual.
► Attach accessories as described in this
User Manual or in the User Manual for the
accessories.
►Tighten loose screws and fastening parts.
► If the cutting attachment rotates when the
engine is idling: Rectify the malfunction.
► Never insert objects into the openings of
the brushcutter.
► Replace worn or damaged labels.
English 4 Safety Precautions
6 0458-507-0121-B

► If you are unsure: Consult a STIHL servic‐
ing dealer.
4.6.2 Deflector
The deflector is in a safe condition if the following
points are observed:
–The deflector is not damaged.
–If you are using the line limiting blade and
skirt: Line limiting blade and skirt are correctly
fitted.
WARNING
■ If components do not comply with safety
requirements, they will no longer function
properly and safety devices may be rendered
inoperative. This can result in serious injuries.
►Work only with an undamaged deflector.
► If you are using the line limiting blade and
skirt: Work with a correctly fitted line limiting
blade and skirt.
►If you have any queries: Contact your
STIHL servicing dealer.
4.6.3 Mowing Head
The mowing head is in a safe condition if the fol‐
lowing points are observed:
–The mowing head is not damaged.
–The mowing head is not jammed.
–The mowing lines are properly installed.
–The wear limits are not exceeded.
WARNING
■If they are in an unsafe condition, parts of the
mowing head or mowing lines may come off
and be ejected at high speed. They may
cause serious injury to persons.
►Work only with an undamaged mowing
head.
► Never use metal objects in place of the
nylon mowing lines.
► Observe and remain inside the wear limits.
► If you have any doubts, be sure to consult a
STIHL dealer.
4.6.4 Metal cutting attachment
The metal cutting attachment is in a safe condi‐
tion if the following points are observed:
–Metal cutting attachment and mounting hard‐
ware are undamaged.
–Metal cutting attachment is not warped.
–Metal cutting attachment is properly mounted.
–Metal cutting attachment is correctly sharp‐
ened.
–Cutting edges of the metal cutting attachment
have no burrs.
–The wear limits are not exceeded.
–If a metal cutting attachment not manufactured
by STIHL is used, it must not be heavier,
thicker, of a different shape, of a lower quality,
or larger in diameter than the largest metal
cutting attachment approved by STIHL.
WARNING
■If it is not in an safe condition, parts of the
metal cutting attachment may come off and be
thrown at high speed. They may cause serious
injury to persons.
►Never work with a damaged metal cutting
attachment or damaged mounting hard‐
ware.
►Sharpen the metal cutting attachment cor‐
rectly.
► Deburr the cutting edges with a file.
► Have the metal cutting attachment bal‐
anced by a STIHL servicing dealer.
► Observe and remain inside the wear limits.
► Use a metal cutting attachment specified in
these instructions for use.
► If you have any doubts, be sure to consult a
STIHL dealer.
4.7 Fuel Mixture and Refueling
WARNING
■This brushcutter requires a fuel mixture of gas‐
oline and two-stroke engine oil. Mixed fuel and
gasoline are extremely flammable. If fuel mix‐
ture or gasoline make contact with open fire or
hot objects, they can cause a fire or explo‐
sions. Persons may be seriously or fatally
injured and property may be damaged.
►Protect fuel mixture and gasoline from heat
and fire.
► Do not spill fuel mixture or gasoline.
► If fuel is spilled: Wipe up fuel with a cloth
and do not attempt to start engine until all
parts of the brushcutter are dry.
►Do not smoke.
► Never refuel near a fire.
► Shut off the engine and allow it to cool
down before refueling.
► Start the engine at least 3 meters from the
fueling spot, outdoors only.
■ Inhaling fuel fumes and gasoline fumes can
have toxic effects.
► Avoid inhaling fuel fumes or gasoline
fumes.
► Refuel in a well-ventilated location.
■ The brushcutter becomes hot during opera‐
tion. The fuel expands and excess pressure
can build up in the tank. Fuel can escape as a
spray when the fuel tank cap is opened. The
4 Safety Precautions English
0458-507-0121-B 7

escaping fuel can ignite. This may result in
serious injury to the user.
► Allow the brushcutter to cool down first and
then open the fuel tank cap carefully.
■ Clothing that has been in contact with fuel or
gasoline will ignite more easily. Persons may
be seriously or fatally injured and property
may be damaged.
►If your clothing comes into contact with fuel
or gasoline: Change your clothing.
■ Fuel mix, gasoline and two-stroke engine oil
can harm the environment.
► Do not spill fuel, gasoline or two-stroke
engine oil.
► Dispose of fuel mix, gasoline and two-
stroke engine oil in accordance with local
regulations and environmental require‐
ments.
■Fuel, gasoline or two-stroke engine oil can
cause irritation if they come into direct contact
with the skin or eyes.
►Avoid contact with fuel, gasoline and two-
stroke engine oil.
► If skin contact occurs: Wash affected areas
of skin with plenty of water and soap.
► If the event of contact with eyes: Rinse
eyes with plenty of water for at least
15 minutes and consult a doctor.
■The brushcutter's ignition system produces
sparks. Unconfined sparks may cause a fire or
an explosion in an easily combustible or explo‐
sive environment. Persons may be seriously
or fatally injured and property may be dam‐
aged.
►Use the spark plugs described in this
instruction manual.
► Insert and tighten down the spark plug.
► Connect the spark plug boot and press it
down firmly.
■ The brushcutter can become damaged if it is
run with a fuel mixture that includes unsuitable
gasoline or an unsuitable two-stroke engine
oil, and also if an incorrect mix ratio of gaso‐
line and two-stroke engine oil is used.
►Mix the fuel as described in this User Man‐
ual.
■ The mixture of gasoline and two-stroke engine
oil can separate or age if it is stored for a long
period. The brushcutter can be damaged if it is
used with a fuel mix that has become separa‐
ted or has aged.
►Before refueling the brushcutter: Thor‐
oughly mix the fuel.
► Use a mixture of gasoline and two-stroke
engine oil that is not older than 30 days
(STIHL MotoMix: 5 years).
4.8 Working
WARNING
■If the engine is not started properly, the user
may lose control of the trimmer. This may
result in serious injury to the user.
►Start the engine as described in this instruc‐
tion manual.
► If the cutting attachment is touching the
ground or objects: Do not start the engine.
■The slide control is in position for
engine starts. Engine RPM in posi‐
tion is higher than idle speed and the
cutting attachment may rotate as soon as the
engine runs. This may result in serious injury
to the user.
►Do not touch the cutting attachment.
► Start the engine as described in this instruc‐
tion manual.
■ In certain situations, the user may no longer
be able to concentrate on their work. The user
can lose control of the trimmer, stumble or fall
and be seriously injured.
►Work calmly and methodically.
► If light and visibility are poor: Do not use
your trimmer.
► Operate the trimmer alone.
► Keep the cutting attachment close to the
ground.
► Watch out for obstacles.
► Work standing on the ground and keep your
balance.
► If you start feeling fatigue: Take a break.
■ Exhaust gas is produced when the engine is
running. Breathing in exhaust gas can have
toxic effects.Breathing in exhaust gas can
have toxic effects.
►Avoid inhaling exhaust gas.
► Operate the trimmer is a well ventilated
location.
► In the event of nausea, headache, visual
disturbances, problems with hearing or diz‐
ziness: Stop work and seek medical advice.
■The user’s ability to hear and assess noises is
restricted when wearing hearing protection
with the engine running.
►Work calmly and methodically.
■ The user will not be able to control the trimmer
properly if it is operated with the slide control
in position . This may result in serious
injury to the user.
►Check that the slide control is in position
during operation.
► Start the engine as described in this instruc‐
tion manual.
English 4 Safety Precautions
8 0458-507-0121-B

■ The rotating cutting attachment can cut the
user. This may result in serious injury to the
user.
►Do not touch the rotating cutting attach‐
ment.
► If the cutting attachment is blocked by an
object: Shut off the engine. Before clearing
the jam.
■If you work with mowing lines that are too
long, the brush cutter may be damaged.
► Use a suitable deflector with attached line
limiting blade.
■ The machine can be damaged if you open the
throttle while the cutting attachment is blocked
by an object.
►Shut off the engine. before clearing the jam.
■ If the behavior of the trimmer changes during
operation or feels unusual, it may no longer be
in a safe condition. This may result in serious
injury to people and damage to property.
►Stop work and consult a STIHL servicing
dealer.
■ Trimmer vibrations may occur during opera‐
tion.
► Wear gloves.
► Take breaks.
► If signs of a circulatory disturbance occur:
Consult a doctor.
■ If the cutting attachment makes contact with a
foreign object during operation, the object or
parts of it may be thrown at high speed. Per‐
sons may be injured or property may be dam‐
aged.
►Remove foreign objects from the working
area.
■ If the rotating cutting attachment makes con‐
tact with a hard object, sparks may occur and
the cutting attachment may be damaged.
Sparks can cause fires in a flammable envi‐
ronment. Persons may be seriously or fatally
injured, and property may be damaged.
►Do not use in a flammable environment.
► Make sure the cutting attachment is in a
safe condition.
■ Note that the cutting attachment continues to
rotate for a short period after you release the
trigger. Persons may be seriously injured.
►Wait until the cutting attachment comes to a
complete stop.
■ In an emergency, the user may start to panic
and forget to take off the carrying system. This
may result in serious injury to the user.
►Practice taking off the carrying system.
4.9 Reactive Forces
0000-GXX-3025-A1
Kickout can be caused for the following reasons:
–The shaded area or the black area of the rotat‐
ing metal cutting attachment comes into con‐
tact with a solid object and is suddenly braked.
–The rotating metal cutting attachment gets
pinched in the cut.
The risk of kickout is greatest in the black area.
WARNING
■ These situations can abruptly decelerate or
stop rotation of the cutting attachment and
cause the cutting attachment to be thrown to
the right or in the direction of the user (black
arrow). The user can lose control of the trim‐
mer. This can result in serious or fatal injuries.
►Hold the trimmer firmly with both hands.
► Use the working techniques described in
this instruction manual.
► Do not use the black area for cutting.
► Use a combination of cutting attachment,
deflector and carrying system recommen‐
ded in this instruction manual.
►Sharpen the metal cutting attachment cor‐
rectly.
► Cut with the motor running at full speed.
4.10 Transporting
WARNING
■The gearbox can get hot during operation.
There is a risk of burn injuries.
► Do not touch a hot gearbox.
■ The trimmer may turn over or shift during
transport. This may result in personal injuries
and damage to property.
►Shut off the engine.
► If a metal cutting attachment is mounted: Fit
the transport guard.
► Secure the trimmer with lashing straps or a
net to prevent it turning over and moving.
■ The muffler and engine may be hot after a
period of operation. There is a risk of burn
injuries.
4 Safety Precautions English
0458-507-0121-B 9

► Carry the trimmer properly balanced by the
drive tube with the cutting attachment
behind you.
4.11 Storing
WARNING
■Children are not aware of and cannot assess
the dangers of a trimmer and can be seriously
injured.
►Shut off the engine.
► If a metal cutting attachment is mounted: Fit
the transport guard.
► Store the trimmer out of the reach of chil‐
dren.
■ Dampness can corrode the electrical contacts
on the trimmer and metal components. This
can damage the trimmer.
►Store the trimmer in a clean and dry condi‐
tion.
4.12 Cleaning, maintenance and
repair
WARNING
■ The cutting attachment can start rotating unin‐
tentionally if the engine is running during
cleaning, maintenance or repair operations.
This may result in serious injury to people and
damage to property.
►Shut off the engine.
■ The muffler and engine may be hot after a
period of operation. This can result in burn
injuries.
►Wait until the muffler and engine cool down.
■ The gear housing can get hot during opera‐
tion. There is a risk of burn injuries.
► Do not touch a hot gear housing.
■ Aggressive cleaning agents, a water jet or
pointed objects can damage the trimmer,
deflector or the cutting attachment. If the trim‐
mer, deflector and cutting attachment are not
cleaned correctly, components may no longer
function properly or safety devices may be
rendered inoperative. Persons may be seri‐
ously injured.
► Clean the brushcutter, deflector and cutting
attachment as described in this User Man‐
ual.
■If the brushcutter, deflector or cutting attach‐
ment is not maintained or repaired as descri‐
bed in this User Manual, components may no
longer function properly or safety devices may
be rendered inoperative. This can result in
serious or fatal injuries.
► Maintain or repair the brushcutter and the
deflector as described in this User Manual.
► Maintain the cutting attachment as descri‐
bed in the User Manual supplied with the
cutting attachment being used or on the
cutting attachment’s packaging.
■The user can be cut by the sharp cutting
edges while cleaning or maintaining cutting
attachments. This may result in injury to the
user.
► Wear work gloves made of robust
material.
5 Preparing Trimmer for
Operation
5.1 Preparing the Brushcutter for
Operation
The following steps must be performed before
commencing work:
► Ensure that the following components are in
safe condition:
–Brushcutter, 4.6.1.
–Deflector, 4.6.2.
–Mowing head or metal cutting attachment,
4.6.3 or 4.6.4.
►Clean the brushcutter, 15.1.
►Fit the carrying ring, 6.1.
►Mount the bike handle, 6.2.
► Select combination of cutting attachment,
deflector and carrying system, 20.
►Mount the deflector, 6.3.1.
► If you are using a universal deflector together
with a mowing head: Fit the skirt and line limit‐
ing blade, 6.4.1.
► Mount mowing head or metal cutting attach‐
ment, 6.5.1 or 6.6.1.
►Fuel the trimmer, 8.2.
►Fit and adjust the carrying system, 7.1.
►Adjust the bike handle, 7.2.
►Balance the brushcutter, 7.3.
►Check the controls, 10.1.
► If you cannot carry out this work: Do not use
your brushcutter and contact your STIHL
dealer for assistance.
6 Assembling the Trimmer
6.1 Fitting the Carrying Ring
► Shut off the engine.
English 5 Preparing Trimmer for Operation
10 0458-507-0121-B

3
1
4
2
0000-GXX-7851-A0
► Hold the carrying ring (1) against the drive
tube (2) and then press it into position.
► Fit the nut (4).
► Insert and tighten down the screw (3) firmly.
The carrying ring need not be removed again.
6.2 Mounting the Bike Handle
► Shut off the engine.
13
4
2
6
a5
0000-GXX-7805-A1
► Take out the screws (1).
► Place the clamping piece (4) together with the
lower clamping shell (6) at a distance of a = 35
cm from the shaft (5).
► Place the handlebar (3) in the clamping
piece (4).
While doing so, do not clamp the curved part
of the handlebar (3).
► Fit the upper clamping shell (2) so that the
holes are in alignment.
► Insert the screws (1).
► Swing the handlebar (3) up and line it up with
the cutting attachment.
► Tighten the screws (1) securely.
10
12
11
12 8
7
5
3
9
0000-GXX-7806-A1
► Position the control handle (7) and throttle
cable (11) over and along the shaft (5) – do
not twist the control handle (7).
► Remove the screw (9).
► Position the control handle (7) on the handle‐
bar (3) so that the hole of the control han‐
dle (7) is flush with the handlebar (3) and the
throttle trigger (8) is facing the gear housing.
► Fit the nut (10).
► Insert and tighten the screw (9) securely.
► Position the throttle cable retainer (12) and the
throttle cable (11) on the shaft.
The throttle cable (11) must not be kinked or
too tightly constricted – make sure the throttle
trigger moves freely.
► Squeeze the throttle cable retainer (12).
The throttle cable retainer (12) engages in
position with an audible click.
It is not necessary to remove the bike handle
again.
6.3 Mounting and Removing the
Deflector
6.3.1 Mounting the guard
► Shut off the engine.
1
2
0000-GXX-3027-A0
► Push the deflector (1) into the guides on the
gear housing up to the limit stop.
► Insert the screws (2) and tighten them firmly.
6.3.2 Removing the Deflector
► Shut off the engine.
► Take out screws.
► Remove guard.
6.4 Fitting and Removing the Skirt
6.4.1 Fitting the Skirt
► Shut off the engine.
6 Assembling the Trimmer English
0458-507-0121-B 11

3
2
4
0000-GXX-3028-A1
1
► Slide the guide slot in the skirt (2) onto the
deflector (1) – it must snap into position.
► Push the line limiting blade (3) into the slot in
the skirt (2).
► Insert and tighten down the screw (4) firmly.
6.4.2 Removing the Skirt
► Shut off the engine.
1
0000-GXX-3030-A2
2
► Insert stop pin (2) into the hole in the skirt (1).
► Use the stop pin (2) to slide the skirt (1) off the
deflector.
The line limiting blade (1) can be left on the skirt.
6.5 Mounting and Removing the
Mowing Head
6.5.1 Mounting the Mowing Head
► Shut off the engine.
2
3
4
0000-GXX-3031-A0
1
4
1
► Place the thrust plate (2) on the shaft (3) so
that its smaller diameter faces up.
► Fit the mowing head (1) on the shaft (3) and
turn it counterclockwise by hand.
► Insert the stop pin (4) in the bore up to the limit
stop and hold it depressed.
► Turn the mowing head (1) counterclockwise
until the stop pin (4) engages in position.
The shaft (3) is now blocked.
► Tighten down the mowing head (1) firmly by
hand.
► Remove the stop pin (4).
6.5.2 Removing the Mowing Head
► Shut off the engine.
► Insert the stop pin in the bore as far as stop
and hold it depressed.
► Rotate the mowing head until the stop pin
engages in position.
The shaft is now blocked.
► Unscrew the mowing head clockwise.
► Remove the thrust plate.
► Remove stop pin.
6.6 Removing and Installing Metal
Cutting Attachment
6.6.1 Mounting the Metal Cutting Attach‐
ment
► Shut off the engine.
1
0000-GXX-3032-A1
2
3
4
5
6
7
► Place the thrust plate (5) on the shaft (6) so
that its smaller diameter faces up.
► Place the metal cutting attachment (4) on the
thrust plate (5). If you are fitting a circular saw
blade or a grass cutting blade with more than
4 cutting edges: Its cutting edges must face in
the same direction as the arrow on the deflec‐
tor.
► Place the thrust washer (3) on the metal cut‐
ting attachment (4) so that its raised side faces
up.
► Place the rider plate (2) on the thrust washer
(3) so that its closed side faces up.
► Insert the stop pin (7) in the bore as far as
stop and hold it depressed.
English 6 Assembling the Trimmer
12 0458-507-0121-B

► Rotate the metal cutting attachment (4) coun‐
terclockwise until the stop pin (7) engages in
position.
The shaft (6) is now blocked.
► Fit the nut (1) counterclockwise and tighten it
down firmly.
► Remove the stop pin (7).
6.6.2 Removing the metal cutting attach‐
ment
► Shut off the engine.
► Insert the stop pin in the bore up to the limit
stop and hold it depressed.
► Rotate the metal cutting attachment clockwise
until the stop pin engages in position.
The shaft is now blocked.
► Unscrew the mounting nut clockwise.
► Remove the fastening parts, metal cutting tool
and pressure plate.
► Remove the stop pin.
7 Adjusting Trimmer for User
7.1 Fitting and Adjusting the Carry‐
ing System
1 3
22
0000-GXX-4594-A0
► Put on the shoulder strap (1) or full harness
(3).
► Adjust the shoulder strap (1) or full harness (3)
so that the carabiner (2) is about a hand’s
width below your right hip.
7.2 Adjusting the Bike Handle
The bike handle can be set to different positions
to suit the height and reach of the user.
► Shut off the engine.
► Hook the brushcutter from the carrying ring
into the carabiner of the carrying system.
2
1
0000-GXX-7849-A0
► Undo the screws (1).
► Swing the bike handle (2) to the required posi‐
tion.
► Tighten down the screws (1) firmly.
7.3 Balancing the Trimmer
The unit is balanced differently depending on the
cutting attachment used.
If a mowing head, grass cutting blade or brush
knife is fitted:
0000-GXX-7836-A0
The cutting attachment should rest lightly on the
ground.
If a circular saw blade is fitted:
0000-GXX-7808-A0
The saw blade must hover at a height of about
20 cm above the ground.
► Shut off the engine.
7 Adjusting Trimmer for User English
0458-507-0121-B 13

2
1
0000-GXX-7807-A0
► Connect the carrying ring (2) to the carabi‐
ner (1).
► Wait for the trimmer to stop swinging.
► Check position of cutting attachment. If it
needs adjustment:
2
3
0000-GXX-7809-A0
► Loosen the screw (3).
► Move carrying ring (2) up or down the drive
tube until correct balanced position is reached.
► Tighten down the screw (3) firmly.
8 Mixing Fuel and Refueling
the Brushcutter
8.1 Mixing fuel
A video is available for this chapter.
www.stihl.com/sxpweh
The fuel required for this brushcutter is a mixture
of gasoline and two-stroke engine oil, in a mixing
ratio of 1:50.
STIHL recommends you use STIHL MotoMix.
If you mix the fuel yourself, use only STIHL two-
stroke engine oil or another high-performance
engine oil classified as JASO FB, JASO FC,
JASO FD, ISO-L-EGB, ISO-L-EGC or ISO-L-
EGD.
STIHL specifies STIHL HP Ultra two-stroke
engine oil or an equivalent high-performance
engine oil in order to maintain emission limits
over the machine’s service life.
► Make sure that the octane number of the gas‐
oline is at least 90 RON and the ethanol con‐
tent is not more than 10% (for Brazil: 27%).
► Make sure the two-stroke engine oil you are
using meets requirements.
► Depending on the desired amount of fuel,
determine the correct amounts of two-stroke
engine oil and gasoline in a mixing ratio of
1:50. Examples for fuel mixes:
–20 ml Two-stroke engine oil, 1 l gasoline
–60 ml Two-stroke engine oil, 3 l gasoline
–100 ml Two-stroke engine oil, 5 l gasoline
► Pour two-stroke engine oil into a clean
approved fuel canister first and then add gaso‐
line.
► Mix the fuel.
8.2 Fueling the brushcutter
► Shut off the engine.
► Place your trimmer on a level surface so that
the fuel tank cap faces up.
► Use a damp cloth to clean the fuel tank cap
and the area around it.
0000-GXX-4727-A0
► Turn the tank cap counterclockwise until it can
be removed.
► Remove the fuel tank cap.
NOTICE
■ Exposure to light, direct sunlight and extreme
temperatures may accelerate fuel separation
or aging. The brushcutter can be damaged if it
is used with a fuel mix that has become sepa‐
rated or has aged.
►Mix the fuel before topping up.
► Do not top up with fuel stored for more than
30 days (STIHL MotoMix: 5 years).
► When topping up, ensure that no fuel is spil‐
led and that the fuel level remains at least
15 mm under the edge of the tank.
English 8 Mixing Fuel and Refueling the Brushcutter
14 0458-507-0121-B

0000-GXX-4728-A0
► Fit the fuel tank cap on the tank opening.
► Turn the tank cap clockwise and tighten it
down firmly by hand.
The fuel tank is closed.
9 Starting and Stopping the
Engine
9.1 Selecting the correct starting
procedure
When must the engine be prepared for starting?
The engine must be prepared for starting if one
of the following conditions apply:
–The engine is at ambient temperature.
–The engine stopped when accelerated for the
first time.
–The engine stopped because the fuel tank was
empty.
►Prepare engine for start, 9.2 and then start
the engine, 9.3.
When can the engine be started without prepara‐
tion?
The engine can be started without preparation if
it has been running for at least 1 minute and only
shut down for a short work break.
►Starting the engine, 9.3.
9.2 Preparing Engine for Start
► Select the correct starting procedure.
► Place the trimmer on a level surface and make
sure the cutting attachment is not touching the
ground or other objects.
► Remove the transport guard.
2
0000-GXX-6451-A0
15
3
4
► Press the manual fuel pump bulb (1) at least
five times.
►Move the choke lever (2) to position .
► Press down the throttle trigger lockout (4) and
hold it there.
► Pull the throttle trigger (3) and hold it there.
►Move the slide control (5) to position
and hold it there.
► Release the throttle trigger (3) and lockout
lever (4).
The slide control (5) engages in position
.
0000-GXX-4729-A0
► Hold the trimmer with your left hand and press
it against the ground.
► Pull the starter grip slowly with your right hand
until you feel it engage.
► Pull the starter grip quickly and allow the
starter rope to rewind several times until the
engine fires and stops.
► If the engine does not stop: Move the choke
lever to position so that the engine does not
flood.
The engine stops.
9.3 Starting the engine
► Select the correct starting procedure.
► Place the brushcutter on a level surface so
that the cutting attachment does not touch the
ground or other objects.
► Remove the transport guard.
0000-GXX-6452-A0
15
3
4
►Move the choke lever (1) to position .
► Press the throttle trigger lockout (4) and keep
it pressed.
► Press the throttle trigger (3) and keep it
pressed.
9 Starting and Stopping the Engine English
0458-507-0121-B 15

►Move the slide control (5) to position
and hold it there.
► Release the throttle trigger (3) and throttle trig‐
ger lockout (4).
The slide control (5) engages in position
.
0000-GXX-4729-A0
NOTICE
■ The brushcutter can be damaged if pressed
into the ground with your foot or knee.
► Press the brushcutter against the ground
with your left hand. Do not stand or kneel
on the shaft.
► Press the brushcutter against the ground with
your left hand.
► Pull the starter grip slowly with your right hand
until you feel it engage.
► Pull the starter grip quickly and allow the
starter rope to rewind several times until the
engine runs.
► Briefly press the throttle trigger (3).
The slide control (5) springs to position . The
engine runs at idling speed.
► If the cutting attachment rotates when the
engine is idling: Rectify the malfunction.
Idle speed adjustment is not correct.
► If the engine does not start: Prepare the
engine for the start and then try again to start
the engine.
9.4 Stopping the Engine
0000-GXX-6453-A0
3
1
2
► Release the throttle trigger (1) and lockout
lever (2).
The cutting attachment comes to a standstill.
► Move the slide control (3) to posi‐
tion .
The engine stops.
► If the engine does not stop:
►Move the choke lever to position .
The engine stops.
► Do not use your trimmer and contact your
STIHL dealer for assistance.
There is a malfunction in the slide control.
10 Testing the Trimmer
10.1 Checking the Controls
Throttle trigger lockout and throttle trigger
► Shut off the engine.
► Attempt to pull the trigger without depressing
the lockout lever.
► If the trigger can be pulled: Do not use your
trimmer and contact your STIHL dealer for
assistance.
There is a malfunction in the throttle trigger
lockout.
► Press down the throttle trigger lockout and
hold it there.
► Depress the throttle trigger.
► Release the throttle trigger and throttle trigger
lockout.
► If the trigger or trigger lockout is stiff or does
not spring back to the idle position: Do not use
your trimmer and contact your STIHL dealer
for assistance.
Trigger or trigger lockout is faulty.
Throttle cable adjustment
► Start the engine.
► Attempt to pull the trigger without depressing
the lockout lever.
► If the engine accelerates: Adjust the throttle
cable.
Throttle cable adjustment is not correct.
Stopping the engine
► Start the engine.
►Move the slide control to position .
The engine stops.
► If the engine does not stop:
►Move the choke lever to position .
The engine stops.
► Do not use your trimmer and contact your
STIHL dealer for assistance.
There is a malfunction in the slide control.
English 10 Testing the Trimmer
16 0458-507-0121-B

11 Operating the Trimmer
11.1 Adjusting Carburetor for Opera‐
tion at High Altitude
If you use the trimmer at high altitude, the engine
will not deliver optimum power. The carburetor
setting can be adjusted to obtain optimum
engine power.
► Start the engine.
► Warm up the engine by opening and closing
the throttle for about 1 minute.
0000-GXX-3132-A0
H
NOTICE
■ If the trimmer is again used at a low altitude,
the engine may overheat.
► Carry out the standard setting.
► Rotate the high speed screw H clockwise
until the engine delivers optimum power.
11.2 Holding and Controlling the
Trimmer
2
1
0000-GXX-7807-A0
► Connect the carrying ring (2) to the carabi‐
ner (1).
0000-GXX-7850-A0
► Hold the trimmer firmly with your right hand on
the control handle – wrap your thumb around
the handle.
► Hold the trimmer firmly with your the left hand
on the left handle – wrap your thumb around
the handle.
11.3 Mowing
The cutting height is determined by the distance
of the cutting attachment from the ground.
A B
0000-GXX-4731-A2
Mowing with a mowing head (A)
► Swing the brushcutter steadily back and forth
in an arc.
► Move forward slowly in a controlled manner.
Mowing with a grass cutting blade or brush
knife (B)
► Mow with the left-hand side on the metal cut‐
ting attachment.
► Move forward slowly in a controlled manner.
11.4 Saws with a circular saw blade
0000-GXX-3042-A0
► Support the left side of the deflector against
the stem.
► Cut through the stem at full speed.
► A safety distance of at least 2 tree lengths to
the next work area.
11.5 Adjusting Nylon Line
11.5.1 Line Feed on AutoCut Mowing Head
► Tap the rotating mowing head on the ground.
About 30 mm of fresh nylon line is advanced.
The line limiting blade in the deflector trims the
mowing lines to the correct length.
11 Operating the Trimmer English
0458-507-0121-B 17

1
2
0000-GXX-4037-A1
Automatic feed does not operate if the mowing
lines are shorter than 25 mm.
► Shut off the engine.
► Depress the spool (1) on the mowing head
and hold it depressed.
► Pull out the mowing lines (2).
► If the mowing lines (2) cannot be pulled out to
the required length: Replace the spool (1) or
the mowing lines (2).
The spool is empty.
11.5.2 Line Feed on SuperCut Mowing
Heads
Mowing lines are adjusted automatically. The line
limiting blade in the deflector trims the mowing
lines to the correct length.
Automatic feed will not take place if the mowing
lines are shorter than 40 mm.
► Shut off the engine.
► Pull out the mowing lines.
► If the mowing lines cannot be pulled out to
required length: Replace nylon line.
The spool is empty.
12 After Finishing Work
12.1 When Work is Finished
► Shut off the engine.
► Allow trimmer to cool down.
► If the brushcutter is wet: Allow the brushcutter
to dry.
► Clean the brushcutter.
► Clean the deflector.
► Clean the cutting attachment.
► If a metal cutting attachment is mounted: Fit
the matching transport guard.
13 Transporting
13.1 Transporting the Trimmer
► Shut off the engine.
► If a metal cutting attachment is mounted: Fit
the matching transport guard.
Carrying the trimmer
► Carry the trimmer properly balanced by the
drive tube with the cutting attachment behind
you.
Transporting the trimmer in a vehicle
► Secure the trimmer to prevent turnover and
movement.
14 Storing
14.1 Storing the Brushcutter
► Shut off the engine.
► If a metal cutting attachment is mounted: Fit
the appropriate transport guard.
► Ensure that the following conditions are met
when storing the brushcutter:
–The brushcutter is out of the reach of chil‐
dren.
–The brushcutter is clean and dry.
► If you store the trimmer for more than 30 days:
► Remove the cutting attachment.
► Open the fuel tank cap.
► Drain the fuel tank.
► Close the fuel tank.
► If a manual fuel pump is fitted: Press the
manual fuel pump at least 5 times.
► Start the engine and run it at idling speed
until it stops.
15 Cleaning
15.1 Cleaning the Trimmer
► Shut off the engine.
► Allow trimmer to cool down.
► Clean the trimmer with a damp cloth or STIHL
resin solvent.
► Clean cooling air slots with a soft brush.
15.2 Cleaning the Deflector and Cut‐
ting Attachment
► Shut off the engine.
► Clean the deflector and cutting attachment
with a damp cloth or a soft brush.
16 Maintenance
16.1 Maintenance Intervals
The maintenance intervals are dependent on the
environmental and operating conditions. STIHL
recommends the following maintenance inter‐
vals:
After every 25 hours of operation
► Lubricate the gearbox.
After every 100 hours of operation
English 12 After Finishing Work
18 0458-507-0121-B

► Install a new spark plug.
Monthly
► Have fuel tank cleaned by a STIHL servicing
dealer.
► Have pickup body (filter) in fuel tank cleaned
by a STIHL servicing dealer.
Every 12 months
► Have pickup body (filter) in fuel tank replaced
by a STIHL servicing dealer.
16.2 Lubricating the gearbox
2
1
0000082409_002
► Remove screw plug (2).
► If no grease can be seen on the end of the
screw plug (2):
► Screw in the tube of STIHL gear lubri‐
cant (1).
► Squeeze 5 g of STIHL gear grease into the
gear housing.
► Unscrew the tube of STIHL gear lubri‐
cant (1).
► Refit and firmly tighten the screw plug (2) .
► Run the brushcutter for 1 minute without
load.
The STIHL gear lubricant is evenly distrib‐
uted.
16.3 Sharpening and Balancing a
Metal Cutting Attachment
Correctly sharpening and balancing metal cutting
attachments requires a lot of practice.
STIHL recommends you have metal cutting
attachments resharpened and balanced by a
STIHL servicing dealer.
► Sharpen the metal cutting attachment as
described in the instructions and on the pack‐
aging supplied with the cutting attachment you
are using.
17 Repairing
17.1 Repairing the Trimmer and
Cutting Attachment
The trimmer and cutting attachment cannot be
repaired by the user.
► If the trimmer or cutting attachment is dam‐
aged: Do not use your trimmer or cutting
attachment and contact your STIHL servicing
dealer.
18 Troubleshooting
18.1 Troubleshooting Trimmer
Most malfunctions have the same causes.
► Perform the following operations:
► Replace air filter.
► Clean or replace the spark plug.
► Carry out the standard setting.
► Adjust idle speed.
► Adjust carburetor for operation at high altitude.
► If the malfunction still exists: Take the action described in the following table.
Condition Cause Remedy
Engine does not
start.
Insufficient fuel in the
tank.
► Prepare fuel mix and refuel the trimmer.
Engine is flooded. ► Clear the combustion chamber.
Carburetor is too hot. ► Allow trimmer to cool down.
► Before starting the engine: Depress the manual fuel
pump bulb at least ten times.
Carburetor is iced up. ► Allow trimmer to warm up to +10°C.
Engine idles errati‐
cally.
Carburetor is iced up. ► Allow trimmer to warm up to +10°C.
Engine stops while
idling
Carburetor is iced up. ► Allow trimmer to warm up to +10°C.
17 Repairing English
0458-507-0121-B 19

18.2 Replacing the Air Filter
The air filter cannot be cleaned. The air filter
must be replaced if there is a loss of engine or
the air filter is damaged.
► Shut off the engine.
►Move the choke lever to position .
3
2
1
1
0000-GXX-7810-A0
► Take out the screws (1) and remove the filter
cover (2).
► Clean the area around the air filter (3) with a
damp cloth or a soft brush.
► Take out the air filter (3).
32
1
0000-GXX-7811-A0
► Install the new air filter (3).
► Fit the filter cover (2).
► Insert and tighten down the screws (1) firmly.
18.3 Cleaning the Spark Plug
► Shut off the engine.
► Allow trimmer to cool down.
2
1
0000-GXX-4734-A0
► Pull off the spark plug boot (1).
► If the area around the spark plug (2) is soiled:
Clean the spark plug (2) with a cloth.
► Unscrew the spark plug (2).
► Clean the spark plug (2) with a cloth.
► If the spark plug (2) is corroded: Install a new
spark plug (2).
► Insert and tighten down the spark plug (2)
firmly.
► Press the spark plug boot (1) firmly home.
18.4 Standard Setting
► Shut off the engine.
0000-GXX-2946-A0
HL
► Turn the high speed screw (H) counterclock‐
wise as far as stop.
► Turn the low speed screw (L) clockwise as far
as stop.
► Turn the low speed screw (L) 3/4 of a turn
counterclockwise.
18.5 Adjusting Idle Speed
► Carry out the standard setting.
► Start the engine.
► Warm up the engine by opening and closing
the throttle for about 1 minute.
0000-GXX-4782-A0
Engine stops while idling
► Turn the idle speed screw (LA) clockwise until
the cutting attachment begins to rotate.
► Turn the idle speed screw (LA) one full turn
counterclockwise.
Erratic idling behavior or poor acceleration
► Turn the low speed screw (L) clockwise or
counterclockwise until the engine runs and
accelerates smoothly.
Cutting attachment rotates when engine is idling
► Turn the idle speed screw (LA) counterclock‐
wise until the cutting attachment stops rotat‐
ing.
► Turn the idle speed screw (LA) one full turn
counterclockwise.
English 18 Troubleshooting
20 0458-507-0121-B
Other manuals for FS 235
1
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