STIHL FS 38 Owner's Manual

Name: STIHL FS 38
Brand: STIHL
SKU: 2038113
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STIHL FS 38

Instruction Manual

Manual de instrucciones

WARNING

Read and follow all safety precautions in Instruction Manual – improper use can cause serious or fatal injury.

ADVERTENCIA

Lea y siga todas las precauciones de seguridad dadas en el manual de instrucciones – el uso incorrecto puede causar lesiones graves o mortales.

Instruction Manual 1 - 41

Manual de instrucciones 42 - 87

English

Contents

Printing inks contain vegetable oils, paper can be recycled.

Printed on chlorine-free paper Original Instruction Manual

Guide to Using this Manual	2
Safety Precautions and Working
Techniques	3
Approved Combinations of Cutting
Attachment, Deflector, Handle and
Harness	14
Mounting the Loop Handle	15
Mounting the Deflector	15
Mounting the Cutting Attachment	15
Fuel	19
Fueling	20
Starting / Stopping the Engine	20
Operating Instructions	23
Cleaning the Air Filter	23
Engine Management	24
Adjusting the Carburetor	24
Spark Plug	25
Rewind Starter	26
Storing the Machine	27
Replacing Nylon Line	27
Inspections and Maintenance by
Dealer	30
Maintenance and Care	31
Main Parts	33
Specifications	34
Special Accessories	35
Maintenance and Repairs	35
Disposal	36
STIHL Incorporated Federal
Emission Control Warranty
Statement	36

STIHL Incorporated California

Exhaust and Evaporative

Emissions Control Warranty

Statement

Trademarks

	Allowonlypersonswhofullyunderstand
	this manual to operate your trimmer.
38	To receive maximum performance and
38	satisfaction from your STIHL trimmer, it

40is important that you read, understand and follow the safety precautions and the operating and maintenance instructions in chapter "Safety Precautions and Working Techniques" before using your trimmer. For further information you can go to www.stihlusa.com.

Contactyour STIHLdealer or theSTIHL distributor for your area if you do not understandanyoftheinstructionsinthis manual.

WARNING

Because a trimmer is a high-speed cutting tool some special safety precautionsmustbeobservedtoreduce the risk of personal injury. Careless or improperusemaycauseseriousoreven fatal injury.

Makesureyourunitisequippedwiththe properdeflector,handleandharnessfor the type of cutting attachment being used. Always wear proper eye protection.

FS 38

English

Guide to Using this Manual

Pictograms

The meanings of the pictograms attached to or embossed on the machine are explained in this manual.

Dependingonthemodelconcerned,the following pictograms may be on your machine.

Fuel tank for gasoline and engine oil mixture

Press to operate decom- pression valve

Manual fuel pump

Press to operate manual fuel pump

Filler hole for gear lubricant

Air intake summer mode

Air intake winter mode

Handle heating

Symbols in Text

Many operating and safety instructions are supported by illustrations.

The individual steps or procedures describedin themanualmaybemarked in different ways:

N A bullet marks a step or procedure.

A description of a step or procedure that refers directly to an illustration may contain item numbers that appear in the illustration. Example:

N Loosen the screw (1). N 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 and signal words described below:

DANGER

Indicates an imminent risk of severe or fatal injury.

WARNING

Indicates a hazardous situation which, if not avoided, could result in severe or fatal injury.

NOTICE

Indicates a risk of property damage, including damage to the machine or its individual components.

Engineering Improvements

STIHL’s philosophy is to continually improve all of its products. As a result, engineeringchangesandimprovements are made from time to time. Therefore, some changes, modifications and improvements may not be covered in this manual. If the operating characteristics or the appearance of your machine differs from those describedinthismanual,pleasecontact your STIHL dealer for assistance.

FS 38

Safety Precautions and

Working Techniques

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 instruction manual and the safety precautions periodically. Careless or improper use may cause serious or fatal injury.

The terminology utilized in this manual when referring to the power tool reflects the type of cutting attachments that may be mounted on it. The term "trimmer" is used to designate an FS unit that is equipped with a nylon line head or a headwithflexibleplasticblades(i.e.,the PolyCut head.) FS models with an "R" on the nameplate were originally configured(atthetimeofdistribution)as a trimmer with a loop handle.

WARNING

As more fully explained later in these Safety Precautions, to reduce the risk of personal injury, make sure your unit is equipped with the proper handle, harness and deflector for the type of

FS 38

cutting attachment you are using. Use only cutting attachments that are specifically authorized by STIHL for use on your FS model. To reduce the risk of severe or fatal injury from blade contact and / or loss of control, never attempt to use a metal blade on this trimmer.

Have your STIHL dealer show you how to operate your power tool. Observe all applicable local safety regulations, standards and ordinances.

WARNING

Do not lend or rent your power tool without the instruction manual. Be sure that anyone using it understands the information contained in this manual.

WARNING

The use of this machine may be hazardous. If the rotating line or blade comes in contact with your body, it will cut you. When it comes in contact with solid foreign objects such as rocks or bits of metal, it may fling them directly or byricochetinthedirectionofbystanders or the operator. Striking such objects could damage the cutting attachment. Thrown objects, including broken heads or polymer blades, may result in serious or fatal injury to the operator or bystanders.

Use your trimmer equipped with the appropriate cutting attachment only for cutting grass and similar material.

WARNING

Do not use it for other purposes, since misuse may result in personal injury or property damage, including damage to the machine.

English

WARNING

Minors should never be allowed to use this power tool. Bystanders, especially children, and animals should not be allowed in the area where it is in use.

WARNING

Toreducetheriskofinjurytobystanders and damage to property, never let your power tool run unattended. When it is not in use (e.g. during a work break), shut it off and make sure that unauthorized persons do not use it.

Most of these safety precautions and warnings apply to the use of all STIHL trimmers. Different models may have different parts and controls. See the appropriate section of your instruction manual for a description of the controls and the function of the parts of your model.

Safe use of a trimmer involves

1.the operator

2.the power tool

3.the use of the power tool

THE OPERATOR

Physical Condition

You must be in good physical condition and mental health and not under the influence of any substance (drugs, alcohol, etc.) which might impair vision, dexterity or judgment. Do not operate this machine when you are fatigued.

English

WARNING

Be alert – if you get tired, take a break. Tiredness may result in loss of control. Working with any power tool can be strenuous.Ifyouhaveanyconditionthat mightbeaggravatedbystrenuouswork, check with your doctor before operating this machine.

WARNING

Prolonged use of a power tool (or other machines) exposing the operator to vibrations may produce whitefinger disease (Raynaud's phenomenon) or carpal tunnel syndrome.

These conditions reduce the hand's ability to feel and regulate temperature, produce numbness and burning sensations and may cause nerve and circulation damage and tissue necrosis.

All factors which contribute to whitefinger disease are not known, but cold weather, smoking and diseases or physical conditions that affect blood vessels and blood transport, as well as high vibration levels and long periods of exposure to vibration are mentioned as factorsinthedevelopmentofwhitefinger disease. In order to reduce the risk of whitefinger disease and carpal tunnel syndrome, please note the following:

Most STIHL power tools are available with an anti-vibration ("AV") system designed to reduce the transmission of vibrations created by the machine to the operator's hands. An AV system is recommended for those persons using power tools on a regular or sustained basis.

–Wear gloves and keep your hands warm.

–Keep the AV system well maintained. A power tool with loose components or with damaged or worn AV elements will tend to have higher vibration levels.

–Maintain a firm grip at all times, but do not squeeze the handles with constant, excessive pressure. Take frequent breaks.

All the above-mentioned precautions do not guarantee that you will not sustain whitefinger disease or carpal tunnel syndrome. Therefore, continual and regular users should closely monitor the condition of their hands and fingers. If any of the above symptoms appear, seek medical advice immediately.

WARNING

The ignition system of the STIHL unit produces an electromagnetic field of a very low intensity. This field may interfere with some pacemakers. To reduce the risk of serious or fatal injury, persons with a pacemaker should consult their physician and the pacemaker manufacturer before operating this tool.

Proper Clothing

WARNING

To reduce the risk of injury, the operator should wear proper protective apparel.

WARNING

The deflector provided with your power tool will not protect the operator from all foreign objects (gravel, glass, wire, etc.) thrown back by the rotating cutting attachment. Thrown objects may also ricochet and strike the operator.

WARNING

To reduce the risk of injury to your eyes never

operate your power tool unless wearing goggles or properly fitted protec- tive glasses with adequate top and side protection complying with ANSI Z 87.1 (or your applicable national stand- ard.) To reduce the risk of injury to your face STIHL recommends that you also wear a face shield or face screen over your goggles or protective glasses.

Power tool noise may damage your hearing. Wear sound barriers (ear plugs or ear mufflers) to protect your hearing. Continual and regular users should have their hearing checked regularly.

FS 38

Be particularly alert and cautious when wearing hearing protection because your ability to hear warnings (shouts, alarms, etc.) is restricted.

Always wear gloves when handling the machine and metal blades. Heavy-duty, non- slip gloves improve your grip and help to protect your hands.

Clothing must be sturdy and snug-fitting, but allow

complete freedom of movement. Wear long pants made of heavy material to help protect your legs. Do not wear shorts, sandals or go

barefoot.

Avoid loose-fitting jack- ets, scarfs, neckties,

jewelry, flared or cuffed

pants, unconfined long hair or anything that could become caught on branches, brush or the moving parts of the unit. Secure hair so it is above shoulder level.

Good footing is very important. Wear sturdy boots with nonslip soles. Steel-toed safety boots are recommended.

THE POWER TOOL

For illustrations and definitions of the power tool parts see the chapter on "Main Parts."

WARNING

Nevermodifythispowertoolinanyway. Only attachments supplied by STIHL and expressly approved by STIHL for use with the specific STIHL model are authorized. Although certain unauthorized attachments are useable with STIHL power tools, their use may, in fact, be extremely dangerous. For the cutting attachments authorized by STIHL for your unit, see the chapter "Approved Combinations of Cutting Attachment, Deflector, Handle and Harness"intheinstructionmanualorthe STIHL "Cutting Attachments, Parts & Accessories" catalog.

If this tool is subjected to unusually high loads for which it was not designed (e.g. heavy impact or a fall), always check that it is in good condition before continuing work.Checkin particularthat the fuel system is tight (no leaks) and that the controls and safety devices are working properly. Do not continue operating this machine if it is damaged. Incaseofdoubt,haveitcheckedbyyour STIHL servicing dealer.

English

THE USE OF THE POWER TOOL

Transporting the Power Tool

WARNING

To reduce the risk of injury from loss of control and line contact, never carry or transportyourpowertoolwiththecutting attachment moving.

234BA016 KN

It may be carried only in a horizontal position. Grip the shaft in a manner that the machine is balanced horizontally. Keep the hot muffler away from your body and the cutting attachment behind you.

WARNING

Always shut off the engine and make surethecuttingattachmenthasstopped before putting a trimmer down. When transporting it in a vehicle, properly secure it to prevent turnover, fuel spillage and damage to the unit.

Fuel

Your STIHL power tool uses an oilgasoline mixture for fuel (see the chapter on "Fuel" of your instruction manual.)

FS 38

English

WARNING

Gasoline is an extremely flammable fuel. If spilled and ignited by a spark or other ignition source, it can cause fire and seri-

ous burn injury or property damage. Use extreme caution when handling gasoline or fuel mix. Do not smoke or bring any fire or flame near the fuel or the power tool. Note that combusti- ble fuel vapor may escape from the fuel system.

Fueling Instructions

WARNING

To reduce the risk of serious injury from burns, never attempt to refuel the unit until it has been completely removed from the operator.

WARNING

Fuel your power tool in well-ventilated areas, outdoors. Always shut off the engine and allow it to cool before refueling. Gasoline vapor pressure may build up inside the fuel tank depending on the fuel used, the weather conditions and the tank venting system.

In order to reduce the risk of burns and other personal injury from escaping gas vapor and fumes, remove the fuel filler capon yourpowertool carefully so asto allow any pressure build-up in the tank to release slowly. Neverremovethe fuel filler cap while the engine is running.

Selectbare groundforfuelingandmove at least 10 feet (3 m) from the fueling spot before starting the engine. Wipe off any spilled fuel before starting your machine.

WARNING

Check for fuel leakage while refueling and during operation. If fuel leakage is found, do not start or run the engine until the leak is fixed and any spilled fuel has been wiped away. Take care not to get fuel on your clothing. If this happens, change your clothing immediately.

WARNING

Inordertoreducetheriskoffuelspillage and fire from an improperly tightened fuel cap, correctly position and tighten the fuel cap in the fuel tank opening.

Different models may be equipped with different fuel caps.

Toolless cap with grip

001BA220 KN

To do this with this STIHL cap, raise the griponthetopofthecapuntilitisupright at a 90° angle. Insert the cap in the fuel

tank opening with the raised positioning marks on the grip of the cap and on the fuel tank opening lining up. Using the grip, press the cap down firmly while turning it clockwise as far as it will go (approx. 1/4 turn).

Fold the grip flush with the top of the cap. Grip the cap and check for tightness. If the grip does not lie completely flush

with the cap and the detent on the grip does not fit in the correspond- ing recess in the filler opening, or if the cap is loose in the filler opening, the cap is not properly seated and tightened and you must repeat the above steps.

Misaligned, damaged or broken cap

NIfthecapdoesnotdropfullyintothe openingwhenthepositioningmarks line up and/or if the cap does not tighten properly when twisted, the baseofthecapmaybeprematurely rotated (in relation to the top) to the closed position. Such misalignment can result from handling, cleaning or an improper attempt at tightening.

FS 38

001BA227 KN

Left:	Base of cap in closed posi-
	tion (with open space)
Right:	Base of cap correctly posi-
	tioned for installation

001BA226 KN

NTo return the cap to the open position for installation, turn the cap (with the grip up) until it drops fully intothetankopening.Next,twistthe capcounterclockwiseasfarasitwill go (approx. 1/4 turn) – this will twist the base of the cap into the correct position. Then, twist the cap clockwise, closing it normally.

NIf your cap still does not tighten properly, it may be damaged or broken; immediately stop use of the unit and take it to your authorized STIHL dealer for repair.

Screw Cap

WARNING

Unit vibrations can cause an improperly tightened fuel filler cap to loosen or

come off and spill quanti- ties of fuel. In order to reduce the risk of fuel spillage and fire, tighten the fuel filler cap by hand as securely as possible.

See also the "Fueling" chapter in your Instruction Manual for additional information.

Before Starting

WARNING

Alwayscheck yourpowertool forproper condition and operation before starting, particularly the throttle trigger, throttle trigger lockout, stop switch, cutting attachment, deflector and harness. The throttle trigger must move freely and always spring back to the idle position. Never attempt to modify the controls or safety devices. Never use a power tool that is damaged or not properly maintained.

WARNING

Do not attach any cutting attachment to a unit without proper installation of all required parts. Failure to use the proper parts may cause the blade or head to fly off and seriously injure the operator or bystanders.

English

WARNING

Thecuttingattachmentmustbeproperly tightened and in safe operating condition. Inspect for loose parts (nuts, screws, etc.) Replace damaged heads before using the power tool.

Keep the handles clean and dry at all times; it is particularly important to keep themfreeofmoisture,pitch,oil,fuelmix, grease or resin in order for you to maintain a firm grip and properly control your power tool.

WARNING

Check that the spark plug boot is securely mounted on the spark plug – a loose boot may cause arcing that could ignite combustible fumes and cause a fire.

FS 38

English

WARNING

To reduce the risk of personal injury to the operator

from blade or line contact and thrown objects, make sure your unit is equipped with the proper deflector, handle and harness for the type of cutting attachment being used (see chart in the chapter on "Approved Combi- nations of Cutting Attachment, Deflector, Handle and Harness".)

Keep the deflector (and the attached skirt where appropriate) adjusted properly at all times (see chapters on "Mounting the Deflector" and "Mounting the Cutting Attachment" of your instruction manual.)

Arrows on the deflector (as seen from the underside) show the correct direction of rotation of the cutting

attachment. When viewed from above, however, the cutting attachment rotates counterclockwise.

Adjust the hand grip and harness (if you arewearing one)to suityoursize before starting work. The machine should be properly balanced as specified in your instructionmanualforpropercontroland less fatigue in operation. To be better prepared in case of an emergency, practise releasing the unit from the harness as quickly as possible.

Starting

Start the engine at least 10 feet (3 m) from the fueling spot, outdoors only.

Forspecificstartinginstructions,seethe appropriate section of your manual. Place the power tool on firm ground or other solid surface in an open area. Maintain good balance and secure footing.

WARNING

Toreducetheriskofinjuryfrombladeor line contact, be absolutely sure that the cuttingattachmentisclearofyou and all otherobstructionsandobjects,including the ground, because when the engine starts at starting-throttle, engine speed will be fast enough for the clutch to engage and move the cutting attachment.

Once the engine has started, immediately blip the throttle trigger, whichshouldreleasethestartingthrottle and allow the engine to slow down to idle.

With the engine running only at idle, attach the power tool to the spring hook ofyourharnessifyouareusingone(see appropriate chapter of the instruction manual.)

WARNING

Your power tool is a one-person machine. Do not allow other persons in the general work area, even when starting.

WARNING

To reduce the risk of injury from loss of control, do not attempt to "drop start" your power tool.

WARNING

When you pull the starter grip, do not wrap the starter rope around your hand. Do not let the grip snap back, but guide the starter rope to rewind it properly. Failure to follow this procedure may result in injury to your hand or fingers and may damage the starter mechanism.

Important Adjustments

WARNING

To reduce the risk of personal injury from loss of control or contact with the running cutting attachment, do not use your unit with incorrect idle adjustment. At correct idle speed, the cutting attachment should not move. For directions on how to adjust idle speed, see the appropriate section of your instruction manual.

FS 38

If you cannot set the correct idle speed, have your STIHL dealer check your power tool and make proper adjustments and repairs.

During Operation

Holding and Controlling the Power Tool

002BA056 KN

Always hold the unit firmly with both hands on the handles while you are working. Wrap your fingers and thumbs around the handles, keeping the handles cradled between your thumb and forefinger. Keep your hands in this position to have your power tool under control at all times. Make sure your trimmer handles and grips are in good condition and free of moisture, pitch, oil, fuel mix or grease.

WARNING

To reduce the risk of injury from loss of control,neverworkonaladderoronany other insecure support. Never hold the cutting attachment above waist height.

FS 38

WARNING

Never attempt to operate your power tool with one hand. Loss of control of

the power tool resulting in serious or fatal injury may result. To reduce the risk of cut injuries, keep hands and feet away from the cutting attach- ment. Never touch a moving cutting attach- ment with your hand or any other part of your body.

WARNING

Do not overreach. Keep proper footing and balance at all times. Special care mustbetakeninslipperyconditions(wet ground,snow)andindifficult,overgrown terrain.Watchforhiddenobstaclessuch as tree stumps, roots and ditches to avoidstumbling.Forbetterfooting,clear away scrub and cuttings. Be extremely cautious when working on slopes or uneven ground.

Working Conditions

Operate and start your power tool only outdoors in a well ventilated area. Operate it under good visibility and daylight conditions only. Work carefully.

English

WARNING

As soon as the engine is running, this product gen- erates toxic exhaust

fumes containing chemi- cals, such as unburned hydrocarbons (including benzene) and carbon monoxide, that are known to cause respira- tory problems, cancer, birth defects, or other reproductive harm. Some of the gases (e.g. carbon monoxide) may be color- less and odorless. To reduce the risk of serious or fatal injury / illness from inhaling toxic fumes, never run the machine indoors or in poorly venti- lated locations.

WARNING

If the vegetation being cut or the surrounding ground is coated with a chemical substance (such as an active pesticide or herbicide), read and follow the instructions and warnings that accompanied the substance at issue.

WARNING

Inhalation of certain dusts, especially organic dusts such as mold or pollen, can cause susceptible persons to have an allergic or asthmatic reaction.

Substantial or repeated inhalation of dustandotherairbornecontaminants,in particular those with a smaller particle size, may cause respiratory or other illnesses. Control dust at the source

English

where possible. Use good work practices, such as operating the unit so that the wind or operating process directsanydustraisedbythepowertool away from the operator. Follow the recommendations of EPA / OSHA / NIOSH and occupational and trade associations with respect to dust ("particulate matter".) When the inhalation of dust cannot be substantially controlled, i.e., kept at or neartheambient(background)level,the operator and any bystanders should wear a respirator approved by NIOSH / MSHA for the type of dust encountered.

Operating Instructions

WARNING

Donotoperateyourpowertoolusingthe starting throttle lock, as you do not have control of the engine speed.

In the event of an emergency, shut off the engineimmediately– movetheslide control / stop switch to 0 or STOP.

WARNING

The rotating cutting attachment may fling foreign objects directly or by ricochet a great distance.

15m (50ft)

Toreducetheriskofeyeandotherinjury always wear proper eye protection (see the chapter on "Proper Clothing") and ensure that bystanders are at least

50 feet (15 m) away. To reduce the risk ofdamagetoproperty,alsomaintainthis distance from such objects as vehicles orwindows.Anycoworkerswhomustbe in the restricted area should also wear goggles or protective glasses.

Stop the engine and cutting tool immediately if you are approached.

Never use metal blades on this trim- mer. Only mowing heads are

authorized.

WARNING

Before you start work, examine the area for stones, glass, fence wire, metal, trash or other solid objects. The cutting attachment could throw objects of this kind.

WARNING

This trimmer 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 cuttingattachmentismorefullyexposed and the power tool may be more difficult to control.

WARNING

During cutting, check the tightness and theconditionofthecuttingattachmentat regular short intervals with the engine

and attachment stopped. If the behavior of the attachment changes during use, stop the engine immediately, wait until the cutting attachment stops, and check the nut securing the attachment for tightness and the head for cracks, wear and damage.

WARNING

A loose head may vibrate, crack, break or come off the trimmer, which may result in serious or fatal injury. Make sure that the cutting attachment is properly tightened. Use the wrench supplied or one of sufficient length to obtain the proper torque. If the head loosens after being properly tightened, stopworkimmediately.Theretainingnut maybewornordamagedandshouldbe replaced. If the head continues to loosen, see your STIHL dealer. Never use a trimmer with a loose cutting attachment.

WARNING

Replace a cracked, damaged or wornout head or a cracked, bent, warped, damaged, dull or worn out blade immediately,evenifdamageislimitedto superficial cracks. Such attachments may shatter at high speed and cause serious or fatal injury.

WARNING

If the head, blade or deflector becomes clogged or stuck, always shut off the engine and make sure the cutting attachment has stopped before cleaning. Grass, weeds, etc. should be cleaned off the blade or from around the head at regular intervals.

FS 38

WARNING

To reduce the risk of unintentional rotation of the cutting attachment and injury, always shut off the engine and remove the spark plug boot before replacing the cutting attachment. To reduce the risk of injury, always shut off theenginebeforeadjustingthelengthof the nylon line on manually adjustable mowing heads.

WARNING

The gearbox becomes hot during operation. To reduce the risk of burn injury, do not touch the gear housing when it is hot.

WARNING

Never modify your muffler. Any modification could cause an increase in heat radiation, sparks or sound level, thereby increasing the risk of fire, burn injury or hearing loss. You may also permanently damage the engine. Have your muffler serviced and repaired by your STIHL servicing dealer only.

WARNING

Themufflerandotherpartsoftheengine (e.g. fins of the cylinder, spark plug) becomehotduringoperationandremain hot for a while after stopping the engine. Toreduceriskofburns,donottouchthe muffler and other parts while they are hot. Keep the area around the muffler clean. Remove excess lubricant and all debris such as pine needles, branches or leaves. Let the engine cool down

sitting on concrete, metal, bare ground or solid wood (away from any combustible substances.

WARNING

An improperly mounted or damaged cylinder housing or a damaged/deformed muffler shell may interfere with the cooling process of the muffler. 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 muffler is furnished with a spark arresting screen designed to reduce the risk of fire from the emission of hot particles. Never operate your unit with a missing or damaged spark arresting screen.Ifyourgas/oilmixratioiscorrect (i.e., not too rich), this screen will normally stay clean as a result of the heat from the muffler and need no service or maintenance. If you experiencelossofperformanceandyou suspect a clogged screen, have your muffler maintainedby aSTIHLservicing dealer. Some state or federal laws or regulations may require a properly maintained spark arrestor for certain uses.Seethe"Maintenance,Repairand Storing" section of these Safety Precautions. Remember that the risk of a brush or forest fire is greater in hot or dry conditions.

English

WARNING

Some STIHL power tools are equipped with a cata- lytic 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 con- ventional mufflers when the engine returns to idle or is shut off. To reduce the risk of fire and burn injuries when using a cat- alytic converter, always set your power tool down in the upright position and never locate it where the muffler is near dry brush, grass, wood chips or other combustible materi- als while it is still hot.

Using the Cutting Attachments

For an illustration of the various cutting attachments and instructions on proper mounting see the chapter on "Mounting the Cutting Attachment" in your instruction manual.

WARNING

To reduce the risk of severe or fatal injury from blade contact and / or loss of control, never attempt to use a metal blade on this trimmer.

FS 38

English

Using the Mowing Heads

Do not use with mowing line longer than the intended length. With a properly mounted deflector, the built-in linelimiting blade will automatically adjust the line to its proper length.

Using the unit with an overly long nylon cutting line increases the load on the engineandreducesitsoperatingspeed. This causes the clutch to slip continuously and results in overheating and damage to important components (e.g. clutch, polymer housing components.) Such damage could, among other things, cause the cutting attachment to rotate at idle.

000BA019 KN

Mowing heads are to be used only on trimmers equipped with a line-limiting bladeinthedeflectorinordertokeepthe line at the proper length (see "Main Parts" chapter in your instruction manual.)

If the lawn edges are planted with trees or bordered by a fence etc., it is best to use a nylon line head. It achieves a "softer" cut with less risk of damaging tree bark etc. than polymer blades.

However, the polymer-bladed STIHL PolyCut produces a better cut if there arenoplantsalongtheedgeofthelawn. Sharpening is not necessary, and worn polymer blades are easily replaced.

WARNING

To reduce the risk of serious injury, never use wire or metal-reinforced line or other material in place of the nylon cutting lines. Pieces of wire could break off and be thrown at high speed toward the operator or bystanders.

STIHL AutoCut mowing head

Nylon cutting cord advances automatically when tapped against the ground (TapAction)

STIHL PolyCut mowing head 6-3 Uses nonrigid, pivoting polymer blades.

	1	KN
	1	002BA073
		002BA073

	KN
2	002BA074
2

DonotcontinueusingthePolyCutifone of the circular holes (1; arrow) becomes visible or if the projecting rim (2; arrow) has worn away. Install a new mowing head.

WARNING

Ifthewearlimitmarksareignored,there is a risk of the cutting attachment 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 bladesforcracksatregularintervals.Ifa crack is found on one blade, always replace all blades.

STIHL FixCut mowing head Uses pre-cut lengths of nylon line. Observe wear indicators.

FS 38

Do not continue using the mowing head if the raised moldings (1) on the base are missing or worn – see right illustration above. The mowing head mayotherwiseshatterandflyingobjects could result in injury to the operator or bystanders. Install a new mowing head.

MAINTENANCE, REPAIR AND STORING

Maintenance, replacement, or repair of the emission control devices and systems may be performed by any nonroad engine repair establishment or individual. However, if you make a warranty claim for a component which has not been serviced or maintained properly or if nonapproved replacement parts were used, STIHL may deny coverage.

WARNING

Use only identical STIHL replacement partsformaintenanceandrepair.Useof non-STIHL parts may cause serious or fatal injury.

Strictly follow the maintenance and repair instructions in the appropriate sections of your instruction manual.

WARNING

Always stop the engine and make sure that the cutting attachment is stopped before doing any maintenance or repair work or cleaning the power tool. Do not attempt any maintenance or repair work notdescribedinyourinstructionmanual. Have such work performed by your STIHL servicing dealer only.

WARNING

Use the specified spark plug, and make sure it and the ignition lead are always clean and in good condition. Always press the spark plug boot snugly onto the spark plug terminal of the proper size. (Note: If the terminal has a detachable SAE adapter nut, it must be securely attached.) A loose connection between the spark plug and the ignition wire connector in the boot may create arcing that could ignite combustible fumes and cause a fire.

WARNING

Never test the ignition system with the spark plug boot removed from the spark plugorwitharemovedsparkplug,since uncontained sparking may cause a fire.

WARNING

Do not operate your power tool if the mufflerisdamaged,missingormodified. An improperly maintained muffler will increasetheriskoffireandhearingloss. Your muffler is equipped with a sparkarresting screen to reduce the risk of fire; never operate your power tool if the screen is missing, damaged or clogged.

English

Remember that the risk of a brush or forest fire is greater in hot or dry weather.

In California, it is a violation of § 4442 or § 4443 of the Public Resources Code to use or operate gasoline-powered tools on forest-covered, brush-covered or grass-covered land unless the engine’s exhaust system is equipped with a complying spark arrester that is maintained in effective working order. The owner/operator of this product is responsible for properly maintaining the spark arrester. Other states or governmentalentities/agencies,suchas the U.S. Forest Service, may have similar requirements. Contact your local fire agency or forest service for the laws or regulations relating to fire protection requirements.

WARNING

Neverrepairdamagedorbrokenheads. This may cause parts of the cutting attachment to come off and result in serious or fatal injuries.

Tighten all nuts, bolts and screws, except the carburetor adjustment screws, after each use.

Do not clean your machine with a pressure washer. The solid jet of water may damage parts of the machine.

Store the power tool in a dry and high or locked location out of reach of children.

Before storing for longer than a few days, always empty the fuel tank. See chapter "Storing the Machine" in the instruction manual.

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English

Approved Combinations of Cutting Attachment, Deflector, Handle and Harness

Cutting attachment

Deflector

Handle

Harness

1	2	5
		5
		6	7
3	4

234BA014 KN

Approved Combinations

Among other parts, the complete unit in includes:

–Cutting attachment

–Deflector

–Handle

–Shoulder strap (special accessory only)

Select correct combination from the table according to the cutting attachment you intend to use.

Cutting Attachments

Mowing heads

1 STIHL AutoCut C 5-2

2 STIHL AutoCut 5-2

3 STIHL PolyCut 6-3

4STIHL FixCut 5-2

Deflector

5Deflector with blade for mowing heads only (see "Mounting the Deflector").

Handle

6 Loop handle

Harness

7Shoulder strap may be used

WARNING

Based on the cutting attachment being used:

Choose the proper deflector in order to reduce the risk of injury from thrown objects and contact with the cutting attachment.

Makesureyourunitisequippedwiththe proper handle and harness in order to reduce the risk of injury from loss of control and contact with the cutting attachment.

Do not use rigid polymer blades, metal cutting attachments or circular saw blades on this unit.

Only mowing heads may be used on loop-handled trimmers with a curved drive tube.

FS 38

Mounting the Loop Handle		Mounting the Deflector

		1
	5
	50 mm
	(2")
2		4
		3
	A	KN
	A	234BA003
		234BA003

NFit the loop handle (1) on the drive tubeabout15 cm(6")(A) forward of the control handle (2).

NPlace the clamp (3) against the drive tube and push it into the loop handle.

NPlace the square nut (4) in the loop handle,

Ninsert the screw (5) from the other side and tighten it down firmly.

Adjusting loop handle to most comfortable position

N Loosen the screw (5).

NMove the loop handle along the drive tube as required.

N Tighten down the screw (5) firmly.

FS 38

232BA066 KN

NPush the deflector (1) over the clamp (2) as far as stop.

3	KN
	232BA067

NInsertthenut (3)inthehexrecessin the deflector – make sure the holes line up.

NInsert the screw (4) and tighten it down firmly.

English

Mounting the Cutting

Attachment

Preparations

232BA026 KN

NLay your trimmer on its back with theloophandleandshroudpointing downandtheoutputshaftfacing up.

English

Thrust plate

2 4

232BA033 KN

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

NPull the thrust plate (1), if fitted, off the shaft (2).

STIHL PolyCut 6-3 mowing head, STIHL FixCut 5-2 mowing head

NSlip the thrust plate (1) over the shaft (2) and engage the hex recess (3) on the external hexagon (4).

Mounting the mowing head

Keep the instruction sheet for the mowing head in a safe place.

STIHL AutoCut 5-2

2	3
	1
	KN
3	232BA054
3

NFit the spring (1) in the mowing head (2).

NWind the mowing line (3) on to the spool (4).

NThread the nylon line through the sleevesandfitthespoolinthehead.

Theindividualstepsaredescribedinthe instruction sheet supplied.

232BA053 KN

NSlip the mowing head (2) over the shaft (5)andengagehexrecess (7) on the external hexagon (6).

NFit the cap (8) on the mowing head

– screw it clockwise on to the shaft as far as stop and tighten it down firmly.

FS 38

STIHL AutoCut C 5-2

2 ES

2	9
Schnur/LINE	9
	1

681BA018 KN

NSlip the mowing head (2) on to the shaft – as AutoCut 5-2.

NTurn the spool (9) clockwise until the two arrow heads line up – secure the spool in this position.

NInsertthecap (8)inthespool,press it down as far as stop and turn it clockwise at the same time.

NTurn the cap until you feel resistance and then tighten it down

firmly by hand.

STIHL PolyCut 6-3

681BA019 KN

N Fit the thrust plate on the shaft.

NInsert the nut (10) in the mowing head.

NScrew the mowing head (11) clockwise on to the shaft (5) as far as stop.

NBlock the shaft – see "Blocking the Shaft".

N Tighten down the mowing head.

NOTICE

Remove the locking pin.

English

Block the shaft.

NTo 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

English
STIHL FixCut 5-2
5
4
1		KN
		KN
	2	232BA074
		232BA074

NSlip the thrust plate (2) over the shaft.

NPlace the mowing head on the thrust plate (2).

WARNING

Collar (see arrow) must engage the mowing head's mounting hole.

NPush the thrust washer (3) over the shaft (1) so it is seated on the base.

NBlock the shaft – see "Blocking the Shaft".

NUse the combination wrench (5) (special accessory) to screw the mounting nut (4) on to the output shaft 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

NBlock the shaft – see "Blocking the Shaft".

NUnscrew the mowing head counterclockwise.

STIHL FixCut

NBlock the shaft – see "Blocking the Shaft".

NUse 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

232BA007 KN

NHold the rotating mowing head above the ground – tap it on the groundonce–about3 cm(1.2 in)of fresh line is advanced.

NThe 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 (1 in).

If the line is shorter than 2.5 cm (1 in):

WARNING

To reduce the risk of injury, always shut off the engine before adjusting the mowing line by hand.

FS 38

N Turn the trimmer on its back.

NPress down the cap on the spool as far as stop.

NPull 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 the STIHL twostroke engine oil at a mix ratio of 50:1.

Your engine requires a mixture of highquality gasoline and two-stroke air cooled engine oil.

Usemid-gradeunleadedgasolinewitha minimum octane rating of 89 ((R+M)/2) and no more than 10% ethanol content.

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.),butmagnesiumcastingsand catalytic converters as well. This could cause running problems or even damage the engine. For this reason STIHL recommends that you use only high-quality unleaded gasoline!

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.

The ethanol content in gasoline affects engine running speed – it may be necessary to readjust the carburetor if you use fuels with various ethanol contents.

English

WARNING

To reduce the risk of personal injury from loss of control and/or contact with the running cutting tool, do not use your unit with incorrect idle adjustment. At correct idle speed, the cutting tool should not move.

Ifyourpowertoolshowsanincorrectidle adjustment, have your STIHL dealer check your power tool and make proper adjustments and repairs.

The idle speed and maximum speed of the engine change if you switch from a fuel with a certain ethanol content to another fuel with a much higher or lower ethanol content.

This problem can be avoided by always using fuel with the same ethanol content.

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.

WerecommendSTIHLHPUltra2-Cycle Engine Oil since it is specially formulated for use in STIHL engines.

Do not use BIA or TCW rated (twostroke water cooled) mix oils or other mixoilsthatstatetheyareforuseinboth water cooled and air cooled engines (e.g., outboard motors, snowmobiles, chain saws, mopeds, etc.).

WARNING

Take care when handling gasoline. Avoid direct contact with the skin and avoid inhaling fuel vapor. When filling at the pump, first remove the container from your vehicle and place the

FS 38

English

containeronthegroundbeforefilling.To reduce the risk of sparks from static discharge and resulting fire and/or explosion, do not fill fuel containers that are sitting in or on a vehicle or trailer.

The container should be kept tightly closed in order to limit the amount of moisture that gets into the mixture.

The machine‘s fuel tank should be cleaned as necessary.

Fuel mix ages

Only mix sufficient fuel for a few days work,nottoexceed3monthsofstorage. Store in approved fuel-containers only. When mixing, pour oil into the container first, and then add gasoline. Close the container and shake it vigorously by hand to ensure proper mixing of the oil with the fuel.

Gaso-	Oil (STIHL 50:1 or equiva-
line	lent high-quality oils)
US gal.	US fl.oz.

12.6

2 1/2

6.4

512.8

Dispose of empty mixing-oil containers only at authorized disposal locations.

Fueling

232BA046 KN

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.

WARNING

In order to reduce the risk of fire and personalinjuryfromescapinggasvapor and fumes, remove the fuel filler cap carefully so as to allow any pressure build-up in the tank to release slowly.

WARNING

Afterfueling,tightenfuelcapassecurely as possible by hand.

Starting / Stopping the

Engine

Controls

7 1 6

	3
5 4	KN
	232BA080

1Stop switch

2 Throttle trigger lockout

3Throttle trigger

4 Tongue of throttle trigger

5Catch

Positions of stop switch

6I – normal run position – the engine is running or can start

70 – Stop – engine off – the ignition is switched off

FS 38

Starting

233BA047 KN

N Move the stop switch to I.

NPress down the throttle trigger interlock and hold it there.

NSqueezethethrottletriggeruntilthe catch on the tongue (4) can be engaged on the housing (arrow).

NNow release the throttle trigger, tongue and trigger interlock in that order. This is the starting throttle position.

232BA011 KN

N Set the choke lever (8) to g if the engine is cold

efor warm start – also use this posi- tion if the engine has been running but is still cold.

NPressthefuelpumpbulb (9)atleast five times – even if the bulb is already filled with fuel.

English

Starting

232BA012 KN

232TI013 KN

NPlacetheunitontheground:Itmust rest securely on the engine support and the deflector. Check that the cutting attachment is not touching the ground of any other obstacles.

NMake sure you have a safe and secure footing.

NHoldthe unitwithyourlefthandand press it down firmly – your thumb should be under the fan housing.

NOTICE

Do not stand or kneel on the drive tube.

FS 38

English

232BA014 KN

NHold the starter grip with your right hand.

NPull the starter grip slowly until you feelitengageandthengiveitabrisk strong pull.

NOTICE

Do not pull out the starter rope all the way – it might otherwise break.

NDonotletthestartergripsnapback. Guideitslowlybackintothehousing so that the starter rope can rewind properly.

N Continue cranking.

When the engine begins to fire:

232TI015 KN

NAfter no more than five pulls, move the choke lever (8) to e.

N Continue cranking.

As soon as the engine runs

NSqueeze 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.

Shut off the engine.

N Move the stop switch to 0.

If the engine does not start

Choke lever

Ifyoudidnotmovethechokelevertoe quicklyenoughaftertheenginebeganto fire, the combustion chamber is flooded.

N Set the choke lever to e .

NMove the stop switch to I, interlock lever and throttle trigger to the starting throttle position.

NStart 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.

NRemove the spark plug – see "Spark Plug".

N Dry the spark plug.

NCranktheengineseveral timeswith the starter to clear the combustion chamber.

NRefit the spark plug – see "Spark Plug".

N Move the stop switch to I.

NSet the choke lever to e– even if the engine is cold.

N Now start the engine.

Fuel tank run until completely dry

NAfter refueling, press the fuel pump bulb at least five times – even if the bulb is filled with fuel.

NSet the choke lever to suit the engine temperature.

N Start the engine.

FS 38

Operating Instructions

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 enginetocooldown.Emptythefueltank and keep the machine in a dry place, well away from sources of ignition, until you need it again. For longer out-of- service periods – see "Storing the Machine".

Cleaning the Air Filter

If there is a noticeable loss of engine power

2 1

232BA017 KN

N Set the choke lever to g.

NPress in the tab (1) and swing the filter cover (2) down.

NClean away loose dirt from around the filter.

English

232BA018 KN

NRemove 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.

NFit the felt element (3) in the filter housing (4).

NClosethefiltercoversothatitsnaps into position.

FS 38

English

Engine Management

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.

Adjusting the Carburetor

General Information

The carburetor comes from the factory with a standard setting.

Thissettingprovidesanoptimumfuel-air mixture under most operating conditions.

Preparations

N Shut off the engine.

N Mounting the Cutting Attachment

NCheck the air filter and clean or replace if necessary.

NCheck the spark arresting screen (not in all models, country-specific) in the muffler and clean or replace if necessary.

Standard Setting

H	L
	LA
	233BA051 KN

NTurn high speed screw (H) counterclockwise as far as stop (no more than 3/4 turn).

NTurn the low speed screw (L) carefully clockwise until it is against its seat, then it back it off a 3/4 turn.

Adjusting Idle Speed

N Carry out the standard setting. N Start and warm up the engine.

Engine stops while idling

NTurn the idle speed screw (LA) slowly clockwise until the engine runs smoothly – the cutting attachment must not rotate.

FS 38

Cuttingattachmentrotateswhenengine is idling

NTurn 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.

Erraticidlingbehavior,pooracceleration (despite correction to setting of LA screw).

Idle setting is too lean

NTurn 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

NTurnthelowspeedscrew (L)slowly clockwise,nofurtherthanstop,until the engine runs and accelerates smoothly.

It is usually necessary to change the settingoftheidlespeedscrew (LA)after every correction to the low speed screw (L).

Fine Tuning for Operation at High Altitude

A slight correction of the setting may be necessary if engine does not run satisfactorily:

FS 38

N Carry out the standard setting. N Warm up the engine.

NTurn 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.

English

Spark Plug

If engine is down on power, difficult to start or runs poorly at idling speed, first check the spark plug.

Fit a new spark plug after approx. 100 operating hours or earlier if the electrodes are badly eroded.

Wrong fuel mix (too much engine oil in the gasoline), a dirty air filter and unfavorable running conditions (mostly at part throttle etc.) affect the condition of the spark plug. These factors cause deposits to form on the insulator nose which may result in trouble in operation.

Removing the Spark Plug

N Move the stop switch to 0.

232BA081 KN

N Pull off the spark plug boot (1). N Unscrew the spark plug.

English

Checking the Spark Plug

	KN
A	000BA039
A

N Clean dirty spark plug.

NCheck electrode gap (A) and readjust if necessary – see "Specifications."

NUseonlyresistortypesparkplugsof the approved range.

Rectify problems that have caused fouling of spark plug:

–too much oil in fuel mix,

–dirty air filter,

–unfavorablerunningconditions,e.g. operating at part load.

000BA071 KN

WARNING

Toreducetheriskoffireandburninjury, use only spark plugs authorized by STIHL.Alwayspresssparkplugboot(1) snuglyontosparkplugterminal(2)ofthe proper size. (Note: If terminal has detachable SAE adapter nut, it must be securely attached.) A loose connection between spark plug boot and ignition wire connector in the boot may create arcing that could ignite combustible fumes and cause a fire.

Installing the spark plug

NScrew home the spark plug, fit the boot and press it down firmly.

Rewind Starter

To help prolong the wear life of the starter rope, observe the following points:

NPull the starter rope only in the direction specified.

NDonotpulltheropeovertheedgeof the guide bushing.

NDo not pull out the rope more than specified.

NDo not allow the starter grip to snap back, guide it back into the housing slowly – see chapter on "Starting / Stopping the Engine."

Have a damaged starter rope replaced by your dealer before it breaks completely. STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer.

FS 38

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