Stihl HL 91 K User Manual

0 (0)

{

STIHL HL 91 K

Instruction Manual

Manual de instrucciones

WARNING

ReadInstructionManualthoroughly before use and follow all safety precautions – improper use can cause serious or fatal injury.

ADVERTENCIA

Antes de usar la máquina 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 - 34

Manual de instrucciones 35 - 73

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	STIHL Incorporated California
Safety Precautions and Working		Exhaust and Evaporative
Techniques	2	Emissions Control Warranty
Using the Unit	11	Statement
Approved Power Tool Attachments	12	Trademarks
Assembling the Unit	13
Fuel	14
Fueling	15
Starting / Stopping the Engine	16
Operating Instructions	18
Cleaning the Air Filter	18
Engine Management	19
Adjusting the Carburetor	19
Spark Plug	20
Lubricating the Gearbox	21
Sharpening Instructions	21
Storing the Machine	22
Inspection and Maintenance by
User	22
Inspections and Maintenance by
Dealer	23
Maintenance and Care	24
Main Parts	26
Specifications	28
Maintenance and Repairs	28
Disposal	29
Limited Warranty	29
STIHL Incorporated Federal
Emission Control Warranty
Statement	29

	Allowonlypersonswhofullyunderstand
	this manual to operate your hedge
	cutter.
31	To receive maximum performance and

33satisfaction from your STIHL hedge cutter, it is 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 hedge cutter. 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 hedge cutter is a high-speed cutting tool some special safety precautionsmustbeobservedtoreduce the risk of personal injury. Careless or improperusemaycauseseriousoreven fatal injury.

HL 91 K

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 manual fuel pump

Filler hole for gear lubricant

Symbols in Text

Many operating and safety instructions are supported by illustrations.

The individual steps or procedures describedinthe manualmaybe marked 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. For 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 a hazardous situation that, if not avoided, will result in death or serious injury.

WARNING

Indicates a hazardous situation that, if not avoided, could result in death or serious 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 or the STIHL distributor for your area for assistance.

Safety Precautions and

Working Techniques

Because a hedge trim- mer is a high-speed, fastcutting power tool with

sharp cutting blades, special safety precau- tionsmustbeobservedto reduce the risk of per- sonal injury.

It is important that you read, fully understand andobservethefollowing safety precautions and warnings. Read the instruction manual and the safety precautions periodically. Careless or improper use may cause serious or fatal injury.

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 cutting tool comes in contact with your body, it will cut you.

Use your hedge trimmer only for cutting hedges, shrubs, scrub, bushes and similar material.

HL 91 K

WARNING

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

WARNING

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

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 hedge trimmers. Different models may have different parts and controls. See the appropriate section of your instruction manual for a description of the controls andthe functionoftheparts of your model.

Safe use of a hedge trimmer involves

1.the operator

2.the power tool

3.the use of the power tool.

HL 91 K

THE OPERATOR

Physical Condition

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

WARNING

Be alert – if you get tired, take a break. Tiredness may result in loss of control. Working with any power tool can be strenuous.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

English

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.

English

Proper Clothing

WARNING

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

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 Z87 "+" (or your applicable national stand- ard).Toreducetheriskof injury to your face STIHL recommends that you also wear a face shield or face screen over your goggles or protective glasses.

Wear an approved safety hard hat to reduce the risk of injury to your head when there is a danger of head injuries.

Power tool noise may damage your hearing. Wear sound barriers (ear plugs or ear mufflers) to protect your hearing. Continualandregularusersshouldhave their hearing checked regularly.

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

Always wear heavy duty workgloves(e.g.madeof leather or other wear resistant material) when handling the machine and the cutting tool. Heavy-duty, nonslip gloves improve your grip and help to protect your hands.

Clothing must be sturdy andsnug-fitting,butallow 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 and Controls".

WARNING

Nevermodifythispowertoolinanyway. Only attachments supplied by STIHL or 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.

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.

THE USE OF THE POWER TOOL

Transporting the Power Tool

WARNING

To reduce the risk of injury from blade contact, never carry or transport your power tool with the cutter blades moving.

HL 91 K

002BA247 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

To reduce the risk of burn injury, do not touch hot parts of the machine and the gear housing when they are hot.

WARNING

Always switch off the engine and fit the scabbard over the cutter blades before transporting the power tool over long distances. When transporting it in a vehicle, properly secure it to prevent turnover, fuel spillage and damage to the unit.

On machines with an adjustable cutter bar: Make sure the cutter bar is secured in position. See chapter in instruction manual entitled "Adjusting Cutter Bar Angle." On machines with a transport position: Move cutter bar to transport position and secure.

Fuel

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

WARNING

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

English

In order to reduce the risk of burns and other personal injury from escaping gas vapor and fumes, remove the fuel filler cap onyour power toolcarefullysoas to allow any pressure build-up in the tank toreleaseslowly. Never remove thefuel filler cap while the engine is running.

Selectbaregroundforfueling andmove 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 whilerefuelingandduring 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.

HL 91 K

English

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

Alwayscheckyour power toolforproper condition and operation before starting, particularly the throttle trigger, throttle trigger lockout, throttle set wheel, stop switch and cutting tool. The throttle trigger must move freely and always spring back to the idle position. Never attempt to modify the controls or safety devices.

WARNING

Check fuel system for leaks, especially the visible parts, e.g., filler cap, hose connections,manual fuelpump (onlyfor powertoolsequippedwithamanualfuel pump). Do not start the engine if there are leaks or damage – risk of fire! Have the machine repaired by a servicing dealer before using it.

WARNING

Never operate your power tool if it is damaged, improperly adjusted or maintained, or not completely or securely assembled.

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.

Keep the handles clean and dry at all times; it is particularly important to keep them free of moisture, pitch, oil, grease orresininorderforyoutomaintainafirm grip and properly control your power tool.

WARNING

The cutting tool must be properly tightened and in safe operating condition. Inspect for loose parts (nuts, screws, etc.) and for cracked, bent, warped or damaged blades. Regularly check the condition and tightness of the cutter blades – with the engine stopped! Replace damaged cutter blades before using the power tool. Always keep blades sharp.

STIHL recommends that you always spray the cutter blades with STIHL resin solvent before starting work – with the engine stopped! You can obtain this protective spray from your dealer. Apply generously.

Starting

On machines with an adjustable cutter bar: Secure the cutter bar in the starting position as described in the chapter "Starting/Stopping the Engine." If this starting position is not the desired cutting position, you will then need to carefully adjust the machine to the desired position once the engine has returned to idle and the blades are no longer moving.

On machines with a defined transport position (cutter bar folded against the drive tube): Never start the machine in the transport position, since the blades arenotengaged inthatpositionandyou therefore cannot visually check to see that they will be stopped at idle when you start to adjust the cutter bar to the desired cutting position (where the blades are engaged).

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

002BA245 KN

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.

HL 91 K

WARNING

To reduce the risk of injury from blade contact, be absolutely sure that the cutting tool is clear of you and all other obstructions and objects, including the ground,becausewhentheenginestarts atstarting-throttleorwiththechokeknob engaged, engine speed will be fast enough for the clutch to engage and move the blades on the cutting tool.

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

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 tool, do not use your unit withincorrectidle adjustment.Atcorrect idle speed, the cutting tool should not move. For directions on how to adjust idle speed, see the appropriate section of your instruction manual.

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

WARNING

This unit is equipped with an ignition system that is normally in operational readiness. After the stop switch is used to stop the engine, it automatically springs back to the "on" position. If the engine is warm, it may be possible to start it by simply pulling the starter rope, with no further adjustments. To reduce the risk of injury, be particularly alert to keep children away from the unit.

During Operation

Holding and Controlling the Power Tool

Always hold the unit firmly with both hands on the handles while you are working.

English

Models with loop handle

002BA246 KN

Placeyourlefthandonhosegripofshaft and your right hand on rear grip and throttle trigger. Wrap your fingers and thumbs around the handles. This also applies to left-handers.

WARNING

Never attempt to operate your power tool with one hand. Loss of control of thepowertoolresultingin seriousorfatalinjurymay result. To reduce the risk

of cut injuries, keep hands and feet away from the cutting tool. Never touch a moving cutting tool 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

HL 91 K

5m (17ft)

English

away fallen branches, scrub and cuttings. Be extremely cautious when working on slopes or uneven ground.

WARNING

To reduce the risk of injury from loss of control,neverworkon aladder,in atree or any other insecure support. Never hold the machine above shoulder height.

Working Conditions

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

WARNING

As soon as the engine is running, this product 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 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 or with the choke knob engaged, as you do not have control of the engine speed.

In the event of an emergency, switch off the engine immediately by pressing the stop switch.

WARNING

Thecutterbladescontinuetomovefora short period after the throttle trigger is released (flywheel effect).

Acceleratingtheenginewhiletheblades are blocked increases the load and will cause the clutch to slip continuously.

This may result in overheating and damage to important components (e.g. clutch, polymer housing components) – whichcanthenincreasetheriskofinjury fromthebladesmovingwhiletheengine is idling.

WARNING

On units with an adjustable cutter bar: To reduce the risk of injury, never touch the blades while making adjustments.

The power tool

hasalargerange.

In order to reduce

the risk of

personal or even fatal injury to

bystanders from falling objects or inadvertent contact with the moving cutter blades of your power tool always keep bystanders at least 17 feet (5 m) away when the power tool is running.

HL 91 K

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

WARNING

Before you start work, examine the hedgeareaforstones,fencewire,metal or other solid objects which could damage the cutter blades.

Take particular care when cutting hedges next to or against wire fences. Do not touch the wire with the cutting blades. When working close to the ground, make sure that no sand, grit or stones get between the cutter blades.

Striking solid foreign objects such as stones, fence wire or metal could damagethecuttingattachmentandmay cause blades to crack, chip or break. STIHL does not recommend the use of your power tool when cutting in areas where the blades could contact such objects.

WARNING

Observe the cutting blades at all times – do not cut any areas of the hedge that you cannot see. When cutting the top of a taller hedge, check the other side of the hedge frequently for bystanders, animals and obstructions.

DANGER

Your power tool is not insulated against electric shock. To reduce the risk of electrocution, never operate this power tool in thevicinityofanywiresor cables (power, etc.) which may be carrying electric current.

WARNING

If the cutting tool becomes clogged or stuck, always turn off the engine and make sure the cutting tool has stopped before cleaning. Grass, weeds, etc. should be cleaned off the cutting tool at regular intervals.

Checkthecuttingbladesatregularshort intervals during operation, or immediately if there is a noticeable change in cutting behavior:

–Shut off the engine.

–Wait until the cutting blades have come to a complete standstill.

–Check condition and tightness, look for cracks.

–Check sharpness.

–Replace damaged or dull cutting toolsimmediately,eveniftheyhave only superficial cracks.

English

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 (e.g. the trunk of a felled tree) 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

HL 91 K

English

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 maintained bya STIHLservicing 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.

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 pro- cess in the muffler. Due to this process, the muf- fler does not cool down as rapidly as conven- tional mufflers when the engine returns to idle or is shut off. To reduce the risk of fire and burn inju- ries when using a catalytic 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 com- bustible materials while it is still hot.

After Finishing Work

Always clean dust and dirt off the machine – do not use any grease solvents for this purpose.

Spray the blades with STIHL resin solvent. Start and run the engine briefly so that the solvent is evenly distributed.

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 section of your instruction manual.

Please also refer to the maintenance chart in this manual.

WARNING

Always stop the engine and make sure that the cutting blades are 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.

Wear gloves when handling or performing maintenance on blades.

WARNING

Use the specified spark plug and make sure it and the ignition lead are always clean and in good condition. Always press spark plug boot snugly onto spark plugterminalofthepropersize.(Note:If terminal has detachable SAE adapter nut, it must be securely attached.) A loose connection between spark plug terminal and the ignition wire connector

HL 91 K

in the boot may create arcing that could ignite combustible fumes and cause a fire.

WARNING

Never test the ignition system with the ignition wire boot removed from the sparkplugorwitharemovedsparkplug, 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. 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

Never repair damaged cutting attachments by welding, straightening or modifying the shape. This may cause parts of the cutting blades to come off and result in serious or fatal injuries.

Keep the cutting blades sharp. 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 this manual.

English

Using the Unit

Cutting Season

Observe country-specific or municipal rules and regulations for cutting hedges.

Do not use your hedge trimmer during rest periods customary in the neighborhood.

Cutting Sequence

Ifa radical cut is necessary, cut a little at a time in several stages.

Use lopping shears to cut out thick branches first.

Cut the sides of the hedge first, then the top.

Disposal

Do not throw cuttings into the garbage can – they can be composted.

Preparations

NModel with adjustable cutter bar: Set the cutter bar to the straight (0°) position.

N Remove the blade scabbard. N Start the engine

HL 91 K

English

Working Techniques

Vertical Cut

445BA001 KN

Extra long reach without the need for other aids.

Swing the cutter bar up and down in an arc as you move along the hedge – use both sides of the cutting blades.

Horizontal Cut

445BA007 KN

Hold the cutter bar at an angle of 0° to 10° as you swing the hedge trimmer horizontally.

445BA002 KN

Swing the cutter bar in an arc towards the outside of the hedge so that the cuttings are swept to the ground.

Recommendation: Only cut hedges that are no more than chest high.

Approved Power Tool

Attachments

The following STIHL attachments may be used with the basic power tool:

Interchangeable
Attachment	Application
HL 0°, 500 mm,	Long reach hedge
with cutter guard	trimmer
HL 0°, 600 mm,	Long reach hedge
with cutter guard	trimmer

HL 91 K

Assembling the Unit

Mounting the Hand Guard

If a cap is fitted on the end of the drive tube:

413BA014 KN

NPull theprotectivecap offtheendof the drive tube and keep it in a safe place.

3 2		1
3 2	4	-5443-A0
5	4	-5443-A0
		0000XXG-

NPush the hand guard (1) over the drive tube (2) as far as stop with its convex side facing the control handle (3).

N Fit washer (4) on the screw (5).

NInsert the screw (5) with washer (4) and tighten it down firmly.

Mounting the Gearbox

5	-A0
	0000-GXX-1855

N Loosen the clamp screws (10).

NPush the gearbox (11) onto the drive tube (5),turnthegearbox (11) back and forth as necessary.

English

0000-GXX-1856-A0

Once the end of the drive tube is inserted beyond the slot in the clamp (12):

NPushthegearbox (11)fullyhomeas far as stop.

NTighten down the clamp screws moderately.

NLine up the gearbox (11) with the powerhead.

NTighten down the clamp screws firmly.

HL 91 K

English

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.

NOTICE

Fuelwithanoctaneratingbelow89may 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 damage the engine. For this reason STIHL recommends that you use only quality unleaded gasoline!

NOTICE

Gasoline with an ethanol content of more than 10% can cause running problems and major damage in engines and should not be used.

For further details, see www.STIHLusa.com/ethanol

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

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 an incorrect idle adjustment. At correct idle speed, the cutting tool should not move.

If your machine’s idle speed is incorrectly adjusted, have your authorized STIHL servicing dealer check your machine and make the 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 a fuel with a much higher or lower ethanol content.

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

Toensurethemaximumperformanceof your STIHL engine, use a high quality 2- cycleengineoil.Tohelpyourenginerun cleaner and reduce harmful carbon deposits, STIHL recommends using STIHLHPUltra2-cycleengineoilorask your dealer for an equivalent fully synthetic 2-cycle engine oil.

To meet the requirements of EPA and CARB we recommend to use STIHL HP Ultra oil.

STIHL MotoMix

STIHL recommends the use of STIHL MotoMix. STIHL MotoMix has a high octane rating and ensures that you always use the right gasoline/oil mix ratio.

STIHL MotoMix uses STIHL HP Ultra two-stroke engine oil suited for high performance engines.

For further details, see www.STIHLusa.com/ethanol

If not using MotoMix, use only STIHL two-stroke engine oil or equivalent highquality two-stroke engine oils that are designed for use in air cooled two-cycle engines.

The use of non-seasonal gasoline blends may increase the potential for pressure to build in the fuel tank during operation. For example, using a winter blend during the summer will increase pressure in the fuel tank. Always use gasoline blends appropriate to the season, altitude and other environmental factors.

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 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.

HL 91 K

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

Fuel mix ages

If not using MotoMix, only mix sufficient fuelforafewdaysofwork,nottoexceed 30 days of storage. Store in approved fuel-containers only. When mixing, pour oil into the container first, and then add gasoline.Closethecontainerandshake it vigorously by hand to ensure proper mix of oil and gasoline.

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.

HL 91 K

Fueling

Preparations

0208BA019 KN

WARNING

Whenfuelingonaslope,alwaysposition the machine so that the filler cap is facing uphill.

NOn level ground, position the machine so that the filler cap is facing up.

NBefore fueling, clean the filler cap andtheareaaroundittoensurethat no dirt falls into the tank.

Always thoroughly shake the mixture in the canister before fueling your machine.

WARNING

To reduce the risk of fire and personal injuries due to escaping fuel and vapor, remove the fuel filler cap carefully so thatanyexcesspressureinthetankcan

English

escape slowly. Use the proper seasonal gasoline blend, i.e., winter blend in winter, summer blend in summer.

Opening the screw cap

0208BA020 KN

NTurn the cap counterclockwise until it can be removed from the tank opening.

N Remove the filler cap.

Refueling

Take care not to spill fuel while fueling and do not overfill the tank.

Closing the screw cap

0208BA021 KN

N Position cap.

NTurn the cap clockwise as far as it will go and tighten it as securely as possible by hand.

English

Starting / Stopping the

Engine

Controls

0208BA066 KN

1 Throttle trigger lockout

2Throttle trigger

3Stop switch with Run and Stop positions. Depress the stop switch (…) to switch off the ignition – see "Functionofstopswitchandignition system".

4Throttle set wheel – limits travel of throttle trigger – see "Function of throttle set wheel".

Function of stop switch and ignition system

The ignition is switched off and the engine stopped when the stop switch is pressed. The stop switch returns automaticallytotheRunpositionwhenit

is released: The ignition is switched on againaftertheenginestops–theengine is then ready to start.

Function of throttle set wheel

4 KN0208BA067

The throttle set wheel (4) enables the travel of the throttle trigger to be preset anywhere between idle and full throttle.

–Turn throttle set wheel (4) in direction of – to reduce throttle trigger travel and maximum engine speed.

–Turn throttle set wheel (4) in direction of + to increase throttle trigger travel and maximum engine speed.

–It is possible to override the preset stop and open the throttle wide by pullingthethrottletriggerfirmly–the presetstopremainsunaffected.The original setting is restored when the throttle trigger is released.

Starting the Engine

5	KN
	0208BA029

NPress the manual fuel pump

bulb (5) at least five times – even if the bulb is already filled with fuel.

Cold engine (cold start)

6	KN
	0208BA030

NTurn choke knob (6) and then push it in at g

Also use this setting if the engine has been running but is still cold.

–Turnthrottlesetwheelindirectionof + as far as stop.

Hot engine (hot start)

NChoke knob (6) remains in F position.

HL 91 K

English

Cranking

1191BA014 KN

NPlacetheunitontheground:Itmust rest securely on the engine support and the gearbox housing.

NOn units with an adjustable cutter bar and defined transport position: Set the cutter bar to the straight(0°) position.

NIf fitted: Remove blade scabbard from the cutting blades.

To reduce the risk of accidents, check that the cutting blades are not touching the ground of any other obstacles.

NMake sure you have a firm footing, either standing, stooping or kneeling.

NHold the unit firmly on the ground with your left hand and press down

– do not touch the throttle trigger, lockout lever or stop switch.

NOTICE

Do not stand or kneel on the drive tube.

1191BA015 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.

NContinue cranking until the engine runs.

As soon as the engine runs

At temperatures below +10 °C (+50 °F)

Warm up the engine for at least 10 seconds in position g.

At temperatures above +10 °C (+50°F)

Warm up the engine for at least 5 seconds in position g.

1191BA025 KN

NDepress throttle trigger lockout and pull the throttle trigger – the choke knob moves to the Run Fposition.

Warm up a cold engineat varying speeds.

WARNING

Make sure the carburetor is correctly adjusted. The cutting blades must not move when the engine is idling.

Your machine is now ready for operation.

Stopping the Engine

NDepress the momentary contact stop switch – the engine stops – release the stop switch – it springs back to the run position.

Other Hints on Starting

Engine stalls in cold start position g.

NDepress throttle trigger lockout and pull the throttle trigger – the choke knob moves to the Run Fposition.

NContinue cranking in position Funtil the engine runs.

HL 91 K

English

Running engine stalls in cold start position gor under acceleration.

NContinue cranking in position Funtil the engine runs.

If the engine does not start

N Check that all settings are correct.

NCheck that there is fuel in the tank and refuel if necessary.

NCheck that the spark plug boot is properly connected.

N Repeat the starting procedure. Engine is flooded

NMove the choke knob to Fand continue cranking until the engine runs.

Fuel tank run until completely dry

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

NSet the choke knob according to engine temperature.

N Now start the engine.

Operating Instructions		Cleaning the Air Filter

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".

If there is a noticeable loss of engine power

0208BA034 KN

N Set knob for warm start (1) to g

NTurn screw (2) in filter cover (3) counterclockwise until the cover is loose

N Remove filter cover (3)

NClean away loose dirt from around the filter

0208BA035KN

NGrip into the recess (4) in the filter housing and remove the felt filter (5)

NReplace felt filter (5) – as a temporarymeasureyoucanknockit out on the palm of you hand or blow it out with compressed air – do not wash

HL 91 K

NOTICE

Replace any damaged parts!

NInsert felt filter (5) form-fittingly into the filter housing

N Set knob for warm start (1) to g

NFitfiltercover (3)–makesurenotto tilt the screw (2) – insert screw and tighten

English

Engine Management		Adjusting the Carburetor

Exhaust emissions are controlled by the design of the engine and components (e.g. carburation, ignition, timing and valve or port timing).

0208BA036 KN

Thecarburetorofthemachinehasbeen adjusted at the factory for optimum performance and fuel efficiency in all operating states.

Setting the idle speed

Engine stops when idling

NTurn the idle speed screw (LA) slowly clockwise until the engine runs smoothly.

Cutting blades move when idling

NTurn the idle speed adjusting screw (LA) slowlycounterclockwise until the cutting blades stop moving

WARNING

If the cutting blades continue to move in idle even after adjustment, have the machine repaired by a STIHL servicing dealer.

HL 91 K

English

Spark Plug

If there is a loss of engine power, the machineisdifficulttostartorrunspoorly at idle, first check the spark plug.

Install a new spark plug after approx. 100 operating hours or earlier if the electrodes are eroded/corroded.

The 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 degrade performance.

Removing the spark plug

0208BA037 KN

NTurn screw (1) in cap (2) until cap can be removed

N Lay down cap

0208BA038 KN

N Unplug spark plug boot (3) N Unscrew spark plug

Checking the Spark Plug

	KN
A	000BA039
A

N Clean dirty spark plug.

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

NUseonlyresistortypesparkplugsof the approved range.

Rectify problems which have caused fouling of spark plug:

–too much oil in fuel mix,

–dirty air filter,

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

0000-GXX-1831-A0

WARNING

Toreducetheriskoffireandburninjury, use only spark plugs authorized by STIHL. Always press the spark plug boot (1) snugly onto the spark plug terminal (2).

Do not use a spark plug with a detachable SAE adapter terminal (3). Arcing may occur that could ignite combustible fumes and cause a fire. This can result in serious injuries or damage to property.

NOnly use resistor type spark plugs with solid, non-threaded terminals

Installing the Spark Plug

NFit the spark plug and tighten it down firmly.

NPress the boot firmly onto the spark plug.

HL 91 K

0208BA039 KN

NFit the cap (1), insert the screw (2) and tighten it down firmly.

HL 91 K

English

Lubricating the Gearbox		Sharpening Instructions

Blade Drive Gear

Lubricate the blade drive gear with STIHLgearlubricantforhedgetrimmers

– see "Special Accessories".

HL 0° version

0000-GXX-1776-A0

NCheck the lubricant level at regular intervals of about every 25 hours of operation. Unscrew the filler

plug (1) – if no grease can be seen on the inside of the filler plug, screw thetubeofgrease intothefillerhole.

NSqueeze up to 10 g (2/5 oz) grease into the gearbox.

NOTICE

Do not completely fill the gearbox with grease.

NUnscrewthetubeofgreasefromthe filler hole.

NRefit the filler plug and tighten it down firmly.

Whencuttingperformanceandbehavior begin to deteriorate, i.e. blades frequently snag on branches: Resharpen the cutting blades.

It is best to have the cutting blades resharpened by a dealer on a workshop sharpener. STIHL recommends an authorized STIHL servicing dealer.

It is also possible to use a flat crosscut sharpening file. Hold the sharpening file at the prescribed angle (see "Specifications").

NOnly sharpen the cutting edges – take care not to file the cutter guard (see “Main Parts”).

NAlways file towards the cutting edge.

NThe file only sharpens on the forward stroke – lift it off the blade on the backstroke.

NUse a whetstone to remove burr from cutting edge.

NRemove as little material as possible.

NAfter sharpening, clean away filing or grinding dust and then spray the cutting blades with STIHL resin solvent.

NOTICE

Donotoperateyourmachinewithdullor damaged cutting blades. This may cause overload and will give unsatisfactory cutting results.

+ 53 hidden pages