STIHL FS 38
{
Instruction Manual
Notice d’emploi
G Instruction Manual
1 - 34
F Notice d’emploi
35 - 70
Contents
English
Guide to Using this Manual 2
Safety Precautions and Working
Techniques 2
Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness 10
Mounting the Loop Handle 11
Mounting the Deflector 11
Mounting the Cutting Attachment 11
Original Instruction ManualPrinted on chlorine-free paper
Fuel 15
Fueling 16
Starting / Stopping the Engine 16
Operating Instructions 19
Cleaning the Air Filter 19
Engine Management 20
Adjusting the Carburetor 20
Spark Plug 21
Rewind Starter 22
Storing the Machine 23
Replacing Nylon Line 23
Inspections and Maintenance by
Dealer 26
Printing inks contain vegetable oils, paper can be recycled.
Maintenance and Care 27
Main Parts 29
Specifications 30
Special Accessories 31
Maintenance and Repairs 32
Disposal 32
CEPA guarantee 32
Dear Customer,
Thank you for choosing a quality
engineered STIHL product.
This machine has been built using
modern production techniques and
comprehensive quality assurance.
Every effort has been made to ensure
your satisfaction and troublefree use of
the machine.
Please contact your dealer or our sales
company if you have any queries
concerning your machine.
Your
Hans Peter Stihl
{
© ANDREAS STIHL AG & Co. KG, 2012
0458-234-8221-B. VA0.K12.
0000002902_007_GB
FS 38
This instruction manual is protected by copyright. All rights reserved, especially the rights to reproduce, translate and process
with electronic systems.
1
English
Guide to Using this Manual
Pictograms
The meanings of the pictograms
attached to the machine are explained in
this manual.
Depending on the model concerned, the
following pictograms may be attached to
your machine.
Fuel tank; fuel mixture of
gasoline and engine oil
Operate decompression
valve
Manual fuel pump
Operate manual fuel
pump
Tube of grease
Intake air: Summer
operation
Intake air: Winter
operation
Handle heating
Symbols in text
WARNING
Warning where there is a risk of an
accident or personal injury or serious
damage to property.
NOTICE
Caution where there is a risk of
damaging the machine or its individual
components.
Engineering improvements
STIHL's philosophy is to continually
improve all of its products. For this
reason we may modify the design,
engineering and appearance of our
products periodically.
Therefore, some changes, modifications
and improvements may not be covered
in this manual.
Safety Precautions and
Working Techniques
Some special safety precautions must be
observed to reduce the
risk of personal injury
when operating this
power tool because of the
very high speed of its cutting attachment.
It is important you read
and understand the
instruction manual before
first use and keep the
manual in a safe place for
future reference. Nonobservance of the
instruction manual may
result in serious or even
fatal injury.
Observe all application local safety
regulations, standards and ordinances.
If you have not used this type of power
tool before: Have your dealer or other
experienced user show you how to
operate your power tool or attend a
special course in its operation.
Minors should never be allowed to use a
power tool.
Keep bystanders, especially children,
and animals away from the work area.
When the power tool is not in use, shut it
off so that it does not endanger others.
Secure it against unauthorized use.
The user is responsible for avoiding
injury to third parties or damage to their
property.
2
FS 38
English
Do not lend or rent your power tool
without the instruction manual. Be sure
that anyone using it understands the
information contained in this manual.
The use of noise emitting power tools
may be restricted to certain times by
national or local regulations.
To operate the power tool you must be
rested, in good physical condition and
mental health.
If you have any condition that might be
aggravated by strenuous work, check
with your doctor before operating a
power tool.
Persons with pacemakers only: The
ignition system of your power tool
produces an electromagnetic field of a
very low intensity. This field may
interfere with some pacemakers. STIHL
recommends that persons with
pacemakers consult their physician and
the pacemaker manufacturer to reduce
any health risk.
Do not operate the power tool if you are
under the influence of any substance
(drugs, alcohol) which might impair
vision, dexterity or judgment.
Depending on the cutting attachment
fitted, use your trimmer only for cutting
grass, wild growth and similar materials.
It must not be used for any other
purpose because of the increased risk of
accidents and damage to the machine.
Never attempt to modify your power tool
in any way since this may result in
accidents or damage to the machine.
Only use cutting attachments and
accessories that are explicity approved
for this power tool model by STIHL or
are technically identical. If you have any
questions in this respect, consult a
servicing dealer. Use only high quality
parts and accessories in order to avoid
the risk of accidents and damage to the
machine.
STIHL recommends the use of original
STIHL replacement parts. They are
specifically designed to match the
product and meet your performance
requirements.
Never attempt to modify your power tool
in any way since this may increase the
risk of personal injury. STIHL excludes
all liability for personal injury and
damage to property caused while using
unauthorized attachments.
Do not use a pressure washer to clean
the power tool. The solid jet of water
may damage parts of the power tool.
The deflector on this power tool cannot
protect the operator from all objects
thrown by the cutting attachment
(stones, glass, wire, etc.). Such objects
may ricochet and then hit the operator.
Clothing and Equipment
Wear proper protective clothing and
equipment.
Clothing must be sturdy
but allow complete freedom of movement. Wear
snug-fitting clothing, an
overall and jacket combination, do not wear a
work coat.
Avoid clothing that could
get caught on branches
or brush or moving parts
of the machine. Do not
wear a scarf, necktie or
jewelry. Tie up and confine long hair (e.g. with a
hair net, cap, hard hat,
etc.).
Wear sturdy shoes with
non-slip soles.
To reduce the risk of
injury from thrown
objects, always wear a
face shield and safety
glasses.
A face shield alone does not provide
adequate eye protection.
Wear hearing protection, e.g. earplugs
or ear muffs.
Wear heavy-duty gloves.
STIHL offers a comprehensive range of
personal protective clothing and
equipment.
FS 38
3
English
234BA001 KN
Transporting the Power Tool
Always turn off the engine.
Carry the unit properly balanced by the
drive tube or loop handle.
In vehicles: Properly secure your power
tool to prevent turnover, fuel spillage and
damage.
Fueling
Gasoline is an extremely
flammable fuel. Keep
clear of naked flames. Do
not spill any fuel – do not
smoke.
Always shut off the engine before
refueling.
Do not fuel a hot engine – fuel may spill
and cause a fire.
Open the fuel cap carefully to allow any
pressure build-up in the tank to release
slowly and avoid fuel spillage.
Fuel your power tool only in wellventilated areas. If you spill fuel, wipe
the machine immediately – if fuel gets on
your clothing, change immediately.
Your power tool comes standard with
either a screw-type or bayonet-type fuel
cap.
After fueling, tighten
down the screw-type fuel
cap as securely as
possible.
Insert the fuel cap with
hinged grip (bayonet-type
cap) correctly in the
opening, turn it clockwise
as far as stop and fold the
grip down.
This reduces the risk of unit vibrations
causing the fuel cap to loosen or come
off and spill quantities of fuel.
To reduce the risk of serious or fatal
burn injuries, check for fuel leakage. If
fuel leakage is found, do not start or run
the engine until leak is fixed.
Before Starting
Check that your power tool is properly
assembled and in good condition – refer
to appropriate chapters in the instruction
manual.
– Use only an approved combination
of cutting attachment, deflector,
handle and harness. All parts must
be assembled properly and
securely. To reduce the risk of
injury, never use metal cutting
attachments.
– Slide control / stop switch must
move easily to STOP or 0
– Smooth action of throttle trigger
interlock (if fitted) and throttle trigger
– the throttle trigger must return
automatically to the idle position.
– Check that the spark plug boot is
secure – a loose boot may cause
arcing that could ignite combustible
fumes and cause a fire.
– Cutting attachment: Check for
correct and secure assembly and
good condition.
– Check protective devices (e.g.
deflector for cutting attachment) for
damage or wear. Always replace
damaged parts. Never operate the
unit with a damaged deflector.
– Never attempt to modify the controls
or safety devices in any way.
– Keep the handles dry and clean –
free from oil and dirt – for safe
control of the power tool.
– Adjust the harness and handle(s) to
suit your height and reach.
To reduce the risk of personal injury, do
not operate your power tool if it is
damaged or not properly assembled.
If you use a shoulder strap or full
harness: Practice removing and putting
down the power tool as you would in an
emergency. To avoid damage, do not
throw the machine to the ground when
practising.
Starting the Engine
Start the engine at least 3 meters from
the fueling spot, outdoors only.
Place the unit on firm ground in an open
area. Make sure you have good balance
and secure footing. Hold the unit
securely. The cutting attachment must
be clear of the ground and all other
obstructions because it may begin to run
when the engine starts.
4
FS 38
English
002BA056 KN
15m (50ft)
Your power tool is a one-person unit. To
reduce the risk of injury from thrown
objects, do not allow other persons
within a radius of 15 meters of your own
position – even when starting.
To reduce the risk of
injury, avoid contact with
the cutting attachment.
Do not drop start the power tool – start
the engine as described in the
instruction manual.
Note that the cutting
attachment continues to
run for a short period
after you let go of the
throttle trigger – flywheel
effect.
Check idle speed setting: The cutting
attachment must not rotate when the
engine is idling with the throttle trigger
released.
To reduce the risk of fire, keep hot
exhaust gases and hot muffler away
from easily combustible materials (e.g.
wood chips, bark, dry grass, fuel).
Holding and Controlling the Power Tool
Always hold the power tool firmly with
both hands on the handles.
Make sure you always have good
balance and secure footing.
Left hand on the loop handle, right hand
on the control handle, even if you are
left-handed.
During operation
In the event of impending danger or in
an emergency, switch off the engine
immediately by moving the slide control
/ stop switch to STOP or 0.
To reduce the risk of injury, do not allow
any other persons within a radius of
15 meters of your own position. To
reduce the risk of damage to property,
also maintain this distance from other
objects (vehicles, windows).
The correct engine idle speed is
important to ensure that the cutting
attachment stops rotating when you let
go of the throttle trigger.
Check and correct the idle speed setting
at regular intervals. If the cutting
attachment still rotates at idle speed,
have your dealer make proper
adjustments or repairs.
Take special care in slippery conditions,
on slopes or uneven ground.
Watch out for obstacles: Roots, tree
stumps or holes which could cause you
to trip or stumble.
Make sure you always have good
balance and secure footing.
Always stand on the ground while
working, never on a ladder, work
platform or any other insecure support.
Be particularly alert and cautious when
wearing hearing protection because
your ability to hear warnings (shouts,
alarms, etc.) is restricted.
To reduce the risk of accidents, take a
break in good time to avoid tiredness or
exhaustion.
Work calmly and carefully – in daylight
conditions and only when visibility is
good. Stay alert so as not to endanger
others.
Your power tool produces
toxic exhaust fumes as
soon as the engine is
running. These fumes
may be colorless and
odorless and contain
unburned hydrocarbons
and benzol. Never run
the engine indoors or in
poorly ventilated locations, even if your model
is equipped with a catalytic converter.
To reduce the risk of serious or fatal
injury from breathing toxic fumes,
ensure proper ventilation when working
in trenches, hollows or other confined
locations.
FS 38
5
English
To reduce the risk of accidents, stop
work immediately in the event of
nausea, headache, visual disturbances
(e.g. reduced field of vision), problems
with hearing, dizziness, deterioration in
ability to concentrate. Apart from other
possibilities, these symptoms may be
caused by an excessively high
concentration of exhaust gases in the
work area.
Operate your power tool so that it
produces a minimum of noise and
emissions – do not run the engine
unnecessarily, accelerate the engine
only when working.
To reduce the risk of fire, do not smoke
while operating or standing near your
power tool. Note that combustible fuel
vapor may escape from the fuel system.
The dusts, vapor and smoke produced
during operation may be dangerous to
health. If the work area is very dusty or
smoky, wear a respirator.
If your power tool is subjected to
unusually high loads for which it was not
designed (e.g. heavy impact or a fall),
always check that it is in good condition
before continuing work – see also
"Before Starting".
Check the fuel system in particular for
leaks and make sure the safety devices
are working properly. Do not continue
operating your power tool if it is
damaged. In case of doubt, have the unit
checked by your servicing dealer.
Do not operate your power tool in the
starting throttle position – engine speed
cannot be controlled in this position.
To reduce the risk
of injury from
thrown objects,
never operate the
power tool without
the proper deflector for the type of
cutting attachment
being used.
Check the work area:
Stones, pieces of metal
or other solid objects can
be thrown and cause personal injury or damage
the cutting attachment
and property (e.g. parked
vehicles, windows).
Special care must be taken when
working in difficult, over-grown terrain.
When cutting high scrub, under bushes
and hedges: Keep cutting attachment at
minimum height of 15 cm to avoid
harming small animals.
Before leaving the power tool
unattended: Shut off the engine.
Check the cutting attachment at regular
short intervals during operation or
immediately if there is a noticeable
change in cutting behavior:
– Turn off the engine. Hold the unit
firmly and press the cutting
attachment into the ground to bring
it to a standstill.
– Check condition and tightness, look
for cracks.
– Replace damaged cutting
attachments immediately, even if
they have only superficial cracks.
Clean grass and plant residue off the
cutting attachment mounting at regular
intervals – remove any build up of
material from the cutting attachment and
deflector.
To reduce the risk of injury, shut off the
engine before replacing the cutting
attachment.
Do not continue using or attempt to
repair damaged or cracked cutting
attachments by welding, straightening or
modifying the shape (out of balance).
This may cause parts of the cutting
attachment to come off and hit the
operator or bystanders at high speed
and
result in serious or fatal injuries.
When using mowing heads
Use only the deflector with properly
mounted line limiting blade to ensure the
mowing lines are automatically trimmed
to the approved length.
To reduce the risk of injury, always turn
off the engine before adjusting the nylon
line of manually adjustable mowing
heads
Using the unit with over-long nylon
cutting lines reduces the motor's
operating speed. The clutch then slips
continuously and this causes
overheating and damage to important
components (e.g. clutch, polymer
housing components) – and this can
increase the risk of injury from the
cutting attachment rotating while the
engine is idling.
6
FS 38
English
Vibrations
Prolonged use of the power tool may
result in vibration-induced circulation
problems in the hands (whitefinger
disease).
No general recommendation can be
given for the length of usage because it
depends on several factors.
The period of usage is prolonged by:
– Hand protection (wearing warm
gloves)
– Work breaks
The period of usage is shortened by:
– Any personal tendency to suffer
from poor circulation (symptoms:
frequently cold fingers, tingling
sensations).
– Low outside temperatures.
– The force with which the handles
are held (a tight grip restricts
circulation).
Continual and regular users should
monitor closely the condition of their
hands and fingers. If any of the above
symptoms appear (e.g. tingling
sensation in fingers), seek medical
advice.
Maintenance and Repairs
Service the machine regularly. Do not
attempt any maintenance or repair work
not described in the instruction manual.
Have all other work performed by a
servicing dealer.
STIHL recommends that you have
servicing and repair work carried out
exclusively by an authorized STIHL
servicing dealer. STIHL dealers are
regularly given the opportunity to attend
training courses and are supplied with
the necessary technical information.
Only use high-quality replacement parts
in order to avoid the risk of accidents
and damage to the machine. If you have
any questions in this respect, consult a
servicing dealer.
STIHL recommends the use of original
STIHL replacement parts. They are
specifically designed to match your
model and meet your performance
requirements.
To reduce the risk of injury, always shut
off the engine before carrying out any
maintenance or repairs or cleaning the
machine. – Exception: Carburetor and
idle speed adjustments.
Do not turn the engine over on the
starter with the spark plug boot or spark
plug removed unless the slide control /
stop switch is on STOP or 0 since there
is otherwise a risk of fire from
uncontained sparking.
To reduce the risk of fire, do not service
or store your machine near open flames.
Check the fuel filler cap for leaks at
regular intervals.
Use only a spark plug of the type
approved by STIHL and make sure it is
in good condition – see "Specifications".
Inspect the ignition lead (insulation in
good condition, secure connection).
Check the condition of the muffler.
To reduce the risk of fire and damage to
hearing, do not operate your machine if
the muffler is damaged or missing. –
Do not touch a hot muffler since burn
injury will result.
Maintenance, replacement, or repair of
the emission control devices and
systems may be performed by any
nonroad engine repair establishment or
individual. However, if you make a
warranty claim for a component which
has not been serviced or maintained
properly or if nonapproved replacement
parts were used, STIHL may deny
coverage.
For any maintenance please refer to the
maintenance chart and to the warranty
statement near the end of the instruction
manual.
Cutting Attachments and Deflectors
For safety reasons only the
combinations of cutting attachment,
deflector, handle and shoulder strap
approved in the model-specific
instruction manual may be used.
Only mowing heads may be used on
trimmers with a curved drive tube and
loop handle.
FS 38
7
English
000BA019 KN
1
002BA073 KN
2
002BA074 KN
Symbols on Deflectors
An arrow shows the direction of rotation
of the cutting attachments.
Mowing Head with Nylon Lines
Nylon line achieves a soft cut for edging
and trimming around fence posts, trees,
etc. – less risk of damaging tree bark.
WARNING
To reduce the risk of injury, never use
steel wire in place of the nylon cutting
line.
STIHL FixCut
Check the wear limit marks!
N If the raised moldings (1) on the
base of the attachment are worn as
shown in the illustration (above
right), do not continue using the
mowing head. Install a new one.
There is otherwise a risk of injury
from thrown parts of the head.
STIHL PolyCut 6-3 Mowing Head with
Polymer Blades
For mowing unobstructed edges of
meadows (without posts, fences, trees
or similar obstacles).
It is important to follow the maintenance
instructions for the Polycut mowing
head.
Check the wear limit marks!
Wear limit marks are integrated in the
base of the PolyCut.
Do not continue using the PolyCut 6-3 if
one of the circular holes (1; arrow)
becomes visible or if the projecting rim
(2; arrow) has worn away. Install a new
mowing head.
8
FS 38
WARNING
If the wear limit marks are ignored, there
is a risk of the cutting tool shattering and
flying parts injuring the operator or
bystanders.
To reduce the risk of accidents from
shattered blades, avoid contact with
stones, metal and similar solid objects.
Check PolyCut blades for cracks at
regular intervals. If a crack is found in
one of the blades, always replace all the
blades.
English
FS 38
9
English
234BA014 KN
1
2
6
7
5
Schnur/LINE 2
Schnur/LINE 1
3
4
Approved Combinations of Cutting Attachment, Deflector, Handle and Harness
Cutting attachment Deflector Handle Shoulder strap
Approved Combinations
Select correct combination from the
table according to the cutting
attachment you intend to use.
WARNING
For safety reasons only the cutting
attachments, deflectors, handles and
shoulder straps shown in each row of
the table may be used together. No
other combinations are permitted
because of the risk of accidents.
Cutting attachments
Mowing heads
1 STIHL AutoCut C 5-2
2 STIHL AutoCut 5-2
3 STIHL FixCut 5-2
4 STIHL PolyCut 6-3
Deflector
5 Deflector with blade for mowing
heads only (see "Mounting the
Deflector")
Handle
6 Loop handle
Shoulder strap
7 Shoulder strap may be used
10
FS 38
English
50 mm
234BA003 KN
5
1
3
4
A
(2")
2
1
2
232BA066 KN
4
232BA067 KN
3
232BA026 KN
Mounting the Loop Handle
Mounting the Deflector
Mounting the Cutting
Attachment
Preparations
N Push the deflector (1) over the
clamp (2) as far as stop.
N Fit the loop handle (1) on the drive
tube about 15 cm (6") (A) forward of
the control handle (2).
N Place the clamp (3) against the
drive tube and push it into the loop
handle.
N Place the square nut (4) in the loop
handle,
N insert the screw (5) from the other
side and tighten it down firmly.
Adjusting loop handle to most
comfortable position
N Loosen the screw (5).
N Move the loop handle along the
drive tube as required.
N Tighten down the screw (5) firmly.
N Insert the nut (3) in the hex recess in
the deflector – make sure the holes
line up.
N Insert the screw (4) and tighten it
down firmly.
N Lay your trimmer on its back with
the loop handle and shroud pointing
down and the output shaft facing up.
FS 38
11
English
232BA033 KN
1
2
3
4
1
232BA054 KN
2
3
4
3
7
5
2
232BA053 KN
6
8
Thrust plate
The thrust plate is shipped with the
PolyCut 6-3 and FixCut 5-2. It is only
required for these mowing heads.
STIHL AutoCut 5-2 mowing head,
STIHL AutoCut C 5-2 mowing head
N Pull the thrust plate (1), if fitted, off
the shaft (2).
STIHL AutoCut 5-2
N Fit the spring (1) in the mowing
head (2).
N Wind the mowing line (3) on to the
spool (4).
N Thread the nylon line through the
sleeves and fit the spool in the head.
The individual steps are described in the
instruction sheet supplied.
N Slip the mowing head (2) over the
shaft (5) and engage hex recess (7)
on the external hexagon (6).
N Fit the cap (8) on the mowing head
– screw it clockwise on to the shaft
as far as stop and tighten it down
firmly.
STIHL PolyCut 6-3 mowing head,
STIHL FixCut 5-2 mowing head
N Slip the thrust plate (1) over the
Mounting the Mowing Head
Keep the instruction sheet for the
mowing head in a safe place.
12
shaft (2) and engage the hex
recess (3) on the external
hexagon (4).
FS 38
English
9
681BA018 KN
Schnur/LINE 2
Schnur/LINE 1
2
8
11
5
681BA019 KN
10
STIHL AutoCut C 5-2
N Slip the mowing head (2) on to the
shaft – as AutoCut 5-2.
N Turn the spool (9) clockwise until
the two arrow heads line up –
secure the spool in this position.
N Insert the cap (8) in the spool, press
it down as far as stop and turn it
clockwise at the same time.
N Turn the cap until you feel
resistance and then tighten it down
firmly by hand.
STIHL PolyCut 6-3
N Fit the thrust plate on the shaft.
N Insert the nut (10) in the mowing
head.
N Screw the mowing head (11)
clockwise on to the shaft (5) as far
as stop.
N Block the shaft – see "Blocking the
Shaft".
N Tighten down the mowing head.
NOTICE
Remove the locking pin.
Blocking the shaft
N To block the shaft, insert a suitable
tool (12) through the holes (13) in
the deflector and thrust plate – turn
the thrust plate back and forth if
necessary.
FS 38
13
English
3
1
2
4
232BA074 KN
5
1
232BA007 KN
2
STIHL FixCut 5-2
N Slip the thrust plate (2) over the
shaft.
N Place the mowing head on the
thrust plate (2).
WARNING
Collar (see arrow) must engage the
mowing head's mounting hole.
N Push the thrust washer (3) over the
shaft (1) so it is seated on the base.
N Block the shaft – see "Blocking the
Shaft".
N Use the combination wrench (5)
(special accessory) to screw the
mounting nut (4) on to the output
shaft clockwise and tighten it down
firmly.
NOTICE
Remove the locking pin.
Removing the mowing head
STIHL AutoCut
N Hold the mowing head steady.
N Unscrew the cap counterclockwise.
STIHL PolyCut
N Block the shaft – see "Blocking the
Shaft".
N Unscrew the mowing head
counterclockwise.
STIHL FixCut
N Block the shaft – see "Blocking the
Shaft".
N Use the combination wrench
(special accessory) to loosen and
unscrew the mounting nut
counterclockwise from the output
shaft.
WARNING
If the mounting nut turns too freely, fit a
new one.
Adjusting Nylon Line
STIHL AutoCut
N Hold the rotating mowing head
above the ground – tap it on the
ground once – about 3 cm fresh line
is advanced.
N The blade (1) on the deflector (2)
trims surplus line to the correct
length – avoid tapping the mowing
head more than once at a time.
Line feed operates only if both lines still
have a minimum length of 2.5 cm.
If the line is shorter than 2.5 cm:
WARNING
To reduce the risk of injury, always shut
off the engine before adjusting the
mowing line by hand.
14
FS 38
English
N Turn the trimmer on its back.
N Press down the cap on the spool as
far as stop.
N Pull the ends of the lines out of the
spool.
If the spool is empty, see "Replacing
Nylon Line".
All other mowing heads
Refer to the instructions supplied with
the mowing head.
WARNING
To reduce the risk of injury, always shut
off the engine before adjusting the
mowing line by hand.
Replacing Nylon Line / Polymer Blades
STIHL AutoCut
See chapter on "Replacing Nylon Line".
STIHL PolyCut, FixCut
Refer to the instructions supplied with
the mowing head.
Fuel
This engine is certified to operate on
unleaded gasoline and with the mix ratio
50:1.
Your engine requires a mixture of highquality premium gasoline and highquality two-stroke air-cooled engine oil.
Use premium branded unleaded
gasoline with a minimum octane rating
of 89 (R+M)/2.
Note: Models equipped with a catalytic
converter require unleaded gasoline. A
few tankfuls of leaded gasoline can
reduce the efficiency of the catalytic
converter by more than 50%.
Fuel with a lower octane rating may
result in preignition (causing "pinging")
which is accompanied by an increase in
engine temperature. This, in turn,
increases the risk of the 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 as
well. This could cause running problems
or even damage the engine. For this
reason it is essential that you use only
high-quality fuels!
Fuels with different percentages of
ethanol are being offered. Ethanol can
affect the running behaviour of the
engine and increase the risk of lean
seizure.
Gasoline with an ethanol content of
more than 10% can cause running
problems and major damage in engines
with a manually adjustable carburetor
and should not be used in such engines.
Engines equipped with M-Tronic can be
run on gasoline with an ethanol content
of up to 25% (E25).
Use only STIHL two-stroke engine oil or
equivalent high-quality two-stroke aircooled engine oils for mixing.
We recommend STIHL 50:1 two-stroke
engine oil since it is specially formulated
for use in STIHL engines.
Do not use BIA or TCW (two-stroke
water cooled) mix oils!
Use only STIHL 50:1 heavy-duty engine
oil or an equivalent quality two-stroke
engine oil for the fuel mix in models
equipped with a catalytic converter.
Take care when handling gasoline.
Avoid direct contact with the skin and
avoid inhaling fuel vapour.
The canister should be kept tightly
closed in order to avoid any moisture
getting into the mixture.
The fuel tank and the canister in which
fuel mix is stored should be cleaned
from time to time.
Fuel mix ratio
Only mix sufficient fuel for a few days
work, not to exceed 3 months of storage.
Store in approved safety fuel-canisters
only. When mixing, pour oil into the
canister first, and then add gasoline.
FS 38
15
English
232BA046 KN
2
232BA080 KN
1
6
7
5
4
3
Examples
Gasoline Oil (STIHL 50:1 or equiva-
lent high-quality oils)
liters liters (ml)
10.02(20)
5 0.10 (100)
10 0.20 (200)
15 0.30 (300)
20 0.40 (400)
25 0.50 (500)
Dispose of empty mixing-oil canisters
only at authorized disposal locations.
Fueling
N Before fueling, clean the filler cap
and the area around it to ensure that
no dirt falls into the tank.
N Position the machine so that the
filler cap is facing up.
N Open the filler cap.
Take care not to spill fuel while fueling
and do not overfill the tank. STIHL
recommends you use the STIHL filler
nozzle (special accessory).
WARNING
After fueling, tighten down the filler cap
as securely as possible by hand.
Starting / Stopping the
Engine
Controls
1 Stop switch
2 Throttle trigger lockout
3 Throttle trigger
4 Tongue of throttle trigger
5 Catch
Positions of stop switch
6I – run
70 – stop
16
FS 38
English
233BA047 KN
4
9
8
232BA011 KN
232BA012 KN
232TI013 KN
Starting
N Move the stop switch to I.
N Press down the throttle trigger
lockout and hold it there.
N Squeeze the throttle trigger until the
catch on the tongue (4) can be
engaged on the housing (arrow).
N Now release the throttle trigger,
tongue and trigger lockout in that
order. This is the starting throttle
position.
N Set the choke lever (8) to
g if the engine is cold
e for warm start – also use this posi-
tion if the engine has been running
but is still cold.
N Press the fuel pump bulb (9) at least
five times – even if the bulb is
already filled with fuel.
Starting
N Place the unit on the ground: It must
rest securely on the engine support
and the deflector. Check that the
cutting attachment is not touching
the ground of any other obstacles.
N Make sure you have a safe and
secure footing.
N Hold the unit with your left hand and
press it down firmly – your thumb
should be under the fan housing.
NOTICE
Do not stand or kneel on the drive tube.
FS 38
17
English
232BA014 KN
8
232TI015 KN
N Hold the starter grip with your right
hand.
N Pull the starter grip slowly until you
feel it engage and then give it a brisk
strong pull.
NOTICE
Do not pull out the starter rope all the
way – it might otherwise break.
N Do not let the starter grip snap back.
Guide it slowly back into the housing
so that the starter rope can rewind
properly.
N Continue cranking.
When the engine begins to fire:
N After no more than five pulls, move
the choke lever (8) to e.
N Continue cranking.
As soon as the engine runs
N Squeeze the throttle trigger to
disengage the tongue – the engine
will settle down to idle speed.
WARNING
Make sure the carburetor is correctly
adjusted. The cutting attachment must
not rotate when the engine is idling.
Your machine is now ready for
operation.
Stop the engine
N Move the stop switch to 0.
If the engine does not start
Choke lever
If you did not move the choke lever to e
quickly enough after the engine began to
fire, the combustion chamber is flooded.
N Set the choke lever to e .
N Move the stop switch to I, lockout
lever and throttle trigger to the
starting throttle position.
N Start the engine by pulling the
starter rope briskly – 10 to 20 pulls
may be necessary.
If the engine still does not start
N Move the stop switch to 0.
N Remove the spark plug – see
"Spark Plug".
N Dry the spark plug.
N Crank the engine several times with
the starter to clear the combustion
chamber.
N Refit the spark plug – see "Spark
Plug".
N Move the stop switch to I.
N Set the choke lever to e – even if
the engine is cold.
N Now start the engine.
Fuel tank run until completely dry
N After refueling, press the fuel pump
bulb at least five times – even if the
bulb is filled with fuel.
N Set the choke lever to suit the
engine temperature.
N Start the engine.
18
FS 38
Operating Instructions Cleaning the Air Filter
232BA017 KN
1
2
232BA018 KN
4
3
English
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 the engine to run for a
short while at idle speed so that engine
heat can be dissipated by the flow of
cooling air. This protects enginemounted components (ignition,
carburetor) from thermal overload.
After Finishing Work
Storing for a short period: Wait for the
engine to cool down. Empty the fuel tank
and keep the machine in a dry place,
well away from sources of ignition, until
you need it again. For longer out-ofservice periods – see "Storing the
Machine".
If there is a noticeable loss of engine
power
N Set the choke lever to g.
N Press in the tab (1) and swing the
filter cover (2) down.
N Clean away loose dirt from around
the filter.
N Remove the felt element (3) from
the filter housing (4) and replace it –
knock out or blow out as a
temporary measure – do not wash.
N Replace damaged parts.
N Fit the felt element (3) in the filter
housing (4).
N Close the filter cover so that it snaps
into position.
FS 38
19
English
L
H
LA
233BA051 KN
Engine Management Adjusting the Carburetor
Exhaust emissions are controlled by the
design of the fundamental engine
parameters and components (e.g.
carburation, ignition, timing and valve or
port timing) without the addition of any
major hardware.
General Information
The carburetor comes from the factory
with a standard setting.
This setting provides an optimum fuel-air
mixture under most operating
conditions.
Preparations
N Shut off the engine.
N Mounting the Cutting Attachment
N Check the air filter and clean or
replace if necessary.
N Check the spark arresting screen
(not in all models, country-specific)
in the muffler and clean or replace if
necessary.
Standard Setting
N Turn high speed screw (H)
counterclockwise as far as stop (no
more than 3/4 turn).
N Turn the low speed screw (L)
carefully clockwise until it is against
its seat, then it back it off a 3/4 turn.
20
Adjusting Idle Speed
N Carry out the standard setting.
N Start and warm up the engine.
Engine stops while idling
N Turn the idle speed screw (LA)
slowly clockwise until the engine
runs smoothly – the cutting
attachment must not rotate.
FS 38
English
1
232BA081 KN
Cutting attachment rotates when engine
is idling
N Turn the idle speed screw (LA)
counterclockwise until the cutting
attachment stops moiving and then
turn the screw another 1/2 to 1 full
turn in the same direction.
WARNING
If the cutting attachment continues to
rotate when the engine is idling, have
your machine checked and repaired by
your servicing dealer.
Erratic idling behavior, poor acceleration
(despite correction to setting of LA
screw).
Idle setting is too lean
N Turn the low speed screw (L)
counterclockwise, no further than
stop, until the engine runs and
accelerates smoothly.
Erratic idling behavior
Idle setting is too rich
N Turn the low speed screw (L) slowly
clockwise, no further than stop, until
the engine runs and accelerates
smoothly.
It is usually necessary to change the
setting of the idle speed screw (LA) after
every correction to the low speed
screw (L).
N Carry out the standard setting.
N Warm up the engine.
N Turn high speed screw (H) slightly
clockwise (leaner) – no further than
stop.
NOTICE
After returning from high altitude, reset
the carburetor to the standard setting.
If the setting is too lean there is a risk of
engine damage due to insufficient
lubrication and overheating.
Spark Plug
N If the engine is down on power,
difficult to start or runs poorly at idle
speed, first check the spark plug.
N Fit a new spark plug after about 100
operating hours – or sooner if the
electrodes are badly eroded. Install
only suppressed spark plugs of the
type approved by STIHL – see
"Specifications".
Removing the Spark Plug
N Move the stop switch to 0.
N Pull off the spark plug boot (1).
N Unscrew the spark plug.
Fine Tuning for Operation at High
Altitude
A slight correction of the setting may be
necessary if engine does not run
satisfactorily:
FS 38
21
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