STIHL MS 291 C-Q Owner's Manual

STIHL MS 291 C-Q
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Instruction Manual Manual de instrucciones
Warning!
To reduce the risk of kickback injury use STIHL reduced kickback bar and STIHL RMC3 (.325“) chain depending on sprocket pitch or other available low kickback components.
Advertencia!
Para reducir el riesgo de lesionarse como resultado de un culatazo, utilice la barra de contragolpe reducido y la cadena RMC3 (0,325 pulg) de STIHL, dependiendo de la rueda dentada usada y de otros componentes reductores de contragolpe.
Read and follow all safety precautions in Instruction Manual – improper use can cause serious or fatal injury.
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 - 60
Manual de instrucciones 61 - 127
Contents
English
Quickstop Plus Chain Brake System 2
Guide to Using this Manual 3 Safety Precautions and Working
Techniques 4 Cutting Attachment 25 Mounting the Bar and Chain (quick
chain tensioner) 25 Tensioning the Saw Chain (quick
Original Instruction ManualPrinted on chlorine-free paper
chain tensioner) 27 Checking Chain Tension 27 Fuel 28 Fueling 29 Chain Lubricant 30 Filling Chain Oil Tank 31 Checking Chain Lubrication 31 Chain Brake 32 Winter Operation 33 Starting / Stopping the Engine 34 Operating Instructions 38 Taking Care of the Guide Bar 39 Shroud 39
Printing inks contain vegetable oils, paper can be recycled.
Air Filter System 40 Cleaning the Air Filter 40 Engine Management 41 Adjusting the Carburetor 41 Spark Arresting Screen in Muffler 42 Spark Plug 42 Replacing the Starter Rope and
Rewind Spring 44 Storing the Machine 46
Checking and Replacing the Chain Sprocket 46
Maintaining and Sharpening the Saw Chain 47
Maintenance and Care 51 Main Parts 53 Specifications 55 Special Accessories 56 Ordering Spare Parts 56 Maintenance and Repairs 57 STIHL Incorporated Federal
Emission Control Warranty Statement 57
Trademarks 59
Allow only persons who fully understand this manual to operate your chain saw.
To receive maximum performance and satisfaction from your STIHL chain saw, 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 chain saw. For further information you can go to www.stihlusa.com.
Contact your STIHL dealer or the STIHL distributor for your area if you do not understand any of the instructions in this manual.
Warning!
Because a chain saw is a high-speed wood-cutting tool, some special safety precautions must be observed as with any other power saw to reduce the risk of personal injury. Careless or improper use may cause serious or even fatal injury.
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© ANDREAS STIHL AG & Co. KG, 2011
0458-576-8621-A. M0-38.B11.DDS.
0000003131_002_GB
MS 291 C-Q
1
English
2
1
150BA000 KN
Quickstop Plus Chain Brake System
This STIHL chain saw is equipped with a chain brake system that can be activated in three different ways. As before, the chain brake can be activated by the inertia of the front hand guard in certain kickback situations or manually by pushing the front hand guard toward the bar nose. In both of these cases the brake, once activated, is designed to bring the chain to a standstill within fractions of a second. In addition, there is a secondary system (STIHL Quickstop Plus) that is designed to stop chain rotation within a second of the operator fully releasing the rear handle. The locked chain is not released again until you press down the throttle trigger lockout to operate the throttle.
The chain brake can be activated in three ways:
3 Manually by fully releasing the rear
handle, including the throttle trigger and throttle trigger lockout.
The activating mechanism for the STIHL Quickstop Plus chain brake system is integrated in the throttle trigger lockout (rear handle). One of the big advantages of this system is that the saw chain is automatically locked in position when carrying the running saw by the front handle (with the rear handle fully released).
To reduce the risk of personal injury or property damage during cutting, observe the characteristics that make this saw different from saws not equipped with a STIHL Quickstop Plus chain brake system. Before operating the chain saw for the first time, make sure you are familiar with how the rear-handle activation works. Pay special attention to the chapter "Chain Brake."
1 By inertia in certain kickback
situations
2 Manually via the front hand guard
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MS 291 C-Q
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Guide to Using this Manual
Pictograms
The meanings of the pictograms attached to or embossed on the machine are explained in this manual.
Depending on the model concerned, the following pictograms may be on your machine.
Fuel tank; fuel mixture of gasoline and engine oil
Chain oil tank; chain oil
Engaging and disengag­ing the STIHL Quickstop chain brake
STIHL Quickstop Plus chain brake system
Direction of chain rotation
Ematic; chain oil quantity control
Tension the chain
Intake air preheating for winter operation
Intake air for summer operation
Handle heating
Operate decompression valve
Operate manual fuel pump
Symbols in Text
Many operating and safety instructions are supported by illustrations.
The individual steps or procedures described in the manual may be 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. 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.
Caution!
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, engineering changes and improvements 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 described in this manual, please contact your STIHL dealer for assistance.
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Safety Precautions and Working Techniques
Because a chain saw 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 instructions periodically. Careless or improper use may cause serious or fatal injury.
Warning!
Reactive forces, including kickback, can be dangerous. Pay special attention to the section on reactive forces.
Have your STIHL dealer show you how to operate your power tool. All safety precautions that are generally observed when working with an axe or a hand saw also apply to the operation of chain saws. Observe all applicable federal, state and local safety regulations, standards and ordinances. When using a chain saw for logging purposes, for instance, refer to the OSHA regulations for "logging operations" at 29 Code of Federal Regulations 1910.266.
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.The saw chain has many sharp cutters. If the cutters contact your flesh, they will cut you, even if the chain is not moving.
Use your chain saw only for cutting wooden objects.
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!
To reduce the risk of injury to bystand­ers 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 chain saws. 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 power tool 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.
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. If you have any condition that might be aggravated by strenuous work, 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.
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MS 291 C-Q
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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 factors in the development of whitefinger disease. In order to reduce the risk of whitefinger disease and carpal tunnel syndrome, please note the following:
Most STIHL power tools are
available with an anti-vibration ("AV") system designed to reduce the transmission of vibrations created by the 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. Heated handles, which are available on some STIHL power­heads, are recommended for cold weather use.
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. Keep the
saw chain sharp. A dull chain will increase cutting time, and pressing a dull chain through wood will increase the vibrations transmitted to your hands.
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.
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 from contact with branches or brush. To reduce the risk of cut injuries, wear pants or chaps that contain pads of cut retardant material. Avoid loose-fitting jack­ets, 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.
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001BA115 KN
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 standard). To reduce the risk of injury to your face STIHL recommends that you also wear a face shield or face screen over your goggles or 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.
Chain saw 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.
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 the cutting
tool. Heavy-duty, nonslip
gloves improve your grip
and help to protect your
hands.
Warning!
Never modify this power tool in any way. 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. Check in particular that 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. In case of doubt, have it checked by your STIHL servicing dealer.
THE USE OF THE POWER TOOL
Transporting the Power Tool
Warning!
To reduce the risk of injury from saw chain contact, never carry or transport your power tool with the saw chain mov­ing. Always engage the chain brake when taking more than a few steps.
Warning!
Always switch off the engine, and fit the chain guard (scabbard) over the chain and guide bar before transporting the power tool over longer distances. When transporting it in a vehicle, properly secure it to prevent turnover, fuel spill­age and damage to the unit.
It may be carried only in a horizontal position. Grip the front handle in a manner that the machine is balanced horizontally. Keep the hot muffler away from your body and the cutting attachment behind you.
Fuel
Your STIHL power tool uses an oil­gasoline mixture for fuel (see the chapter on "Fuel" of your instruction manual).
THE POWER TOOL
For illustrations and definitions of the power tool parts see the chapter on "Main Parts."
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MS 291 C-Q
Warning!
001BA220 KN
001BA227 KN
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 combustible fuel vapor may escape from the fuel system.
Fueling Instructions
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 cap on your power tool carefully so as to allow any pressure build-up in the tank to release slowly. Never remove the fuel filler cap while the engine is running.
Select bare ground for fueling and move at least 10 feet (3 m) from the fueling spot before starting the engine. Wipe off any spilled fuel before starting your 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.
Different models may be equipped with different fuel caps.
Toolless cap with grip
Warning!
In order to reduce the risk of fuel spill­age and fire from an improperly tightened fuel cap, correctly position and tighten the fuel cap in the fuel tank opening.
To do this with this STIHL cap, raise the grip on the top of the cap until it is upright at a 90° angle. Insert the cap in the fuel tank opening with the 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).
English
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 correspond­ing 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
N If the cap does not drop fully into the
opening when the positioning marks line up and/or if the cap does not tighten properly when twisted, the base of the cap may be prematurely rotated (in relation to the top) to the closed position. Such misalignment can result from handling, cleaning or an improper attempt at tightening.
Left: Base of cap in closed posi-
tion (with open space)
Right: Base of cap correctly posi-
tioned for installation
MS 291 C-Q
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001BA226 KN
N To return the cap to the open
position for installation, turn the cap (with the grip up) until it drops fully into the tank opening. Next, twist the cap counterclockwise as far as it will 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.
N If 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 quantities of fuel. In
order to reduce the risk of fuel spillage and fire, tighten the fuel filler cap by hand as securely as possible.
The screwdriver end of the STIHL combination wrench or other similar tool can be used as an aid in tightening slotted fuel filler caps.
See also the "Fueling" chapter in your Instruction Manual for additional information.
Before Starting
Take off the chain guard (scabbard) and inspect the saw for proper condition and operation. (See the maintenance chart near the end of the instruction manual.)
Warning!
Always check your power tool for proper condition and operation before starting, particularly the throttle trigger, throttle trigger lockout, 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!
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.
For proper assembly of the bar and chain follow the procedure described in the chapter "Mounting the Bar and Chain" of your instruction manual. STIHL Oilomatic chain, guide bar and sprocket must match each other in gauge and pitch. Before replacing any bar and chain, see the chapter entitled
"Specifications" in the instruction manual and the sections "Kickback" and the "ANSI B 175.1-2000 chain saw kickback standard" below.
Warning!
Proper tension of the chain is extremely important. In order to avoid improper setting, the tensioning procedure must be followed as described in your man­ual. Always make sure the hexagonal nut(s) for the sprocket cover is (are) tightened securely after tensioning the chain in order to secure the bar. Never start the saw with the sprocket cover loose. Check chain tension once more after having tightened the nut(s) and thereafter at regular intervals (whenever the saw is shut off). If the chain becomes loose while cutting, shut off the engine and then tighten. Never try to adjust the chain while the engine is running!
Keep the handles clean and dry at all times; it is particularly important to keep them free of moisture, pitch, oil, fuel mix, grease or resin in order for you to maintain a firm grip and properly control your power tool.
Starting
Warning!
To reduce the risk of fire and burn inju­ries, start the engine at least 10 feet (3 m) from the fueling spot, outdoors only.
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001BA113 KN
001BA114 KN
Start and operate your saw without assistance. For specific starting instructions, see the appropriate section of the instruction manual. Proper starting methods reduce the risk of injury.
Warning!
To reduce the risk of injury from chain contact and / or reactive forces, the Quickstop chain brake must be engaged by means of the front hand guard when starting the saw. If your saw is equipped with the Quickstop Plus chain brake system, it is not sufficient to engage that brake only for starting, because the chain may begin to rotate at high speed when the throttle trigger lockout is depressed (releasing the brake) in order to blip the throttle trigger after starting.
Warning!
Do not drop start. This method is very dangerous because you may lose con­trol of the saw.
There are two recommended methods for starting your chain saw.
hand guard (see "Chain Brake" chapter in your instruction manual) and place the chain saw on firm ground or other solid surface in an open area. Maintain good balance and secure footing.
Grip the front handlebar of the saw firmly with your left hand and press down. For saws with a rear handle level with the ground, put the toe of your right foot into the rear handle and press down. With your right hand pull out the starter grip slowly until you feel a definite resistance and then give it a brisk, strong pull.
The second recommended method for starting your chain saw allows you to start the saw without placing it on the ground. Make sure the STIHL Quickstop chain brake is engaged by means of the front hand guard, grip the front handle of the chain saw firmly with your left hand. Keep your arm on the front handle in a locked (straight) position. Hold the rear handle of the saw tightly between your legs just above the knees. Maintain good balance and secure footing. Pull the starting grip slowly with your right hand until you feel a definite resistance and then give it a brisk, strong pull.
Warning!
Be sure that the guide bar and chain are clear of you and all other obstructions and objects, including the ground. When the engine is started, the engine speed with the starting throttle lock engaged will be fast enough for the clutch to engage the sprocket and, if the chain brake is not activated, turn the chain. If the upper quadrant of the tip of the bar touches any object, it may cause kick­back to occur (see section on reactive forces). To reduce this risk, always engage the STIHL Quickstop chain brake by means of the front hand guard before starting. Never attempt to start the chain saw when the guide bar is in a cut or kerf.
As soon as the engine is running, immediately blip the throttle trigger, which will disengage the starting throttle lock and allow the engine to settle down to idle.
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.
With the first recommended method, the chain saw is started on the ground. Make sure the STIHL Quickstop chain brake is engaged by means of the front
MS 291 C-Q
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001BA087 LÄ
001BA031 KN
Important Adjustments
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. 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!
To reduce the risk of serious or fatal injury to the oper­ator or bystanders
from loss of con­trol, never use the saw with one hand. It is more difficult for you to control reac­tive forces and to prevent the bar and chain from skating or bouncing along the limb or log. Even for those compact saws designed for use in confined spaces, one-handed operation is dan­gerous because the operator may lose control.
Warning!
Take extreme care in wet and freezing weather (rain, snow, ice). Put off the work when the weather is windy, stormy or rainfall is heavy.
During Operation Holding and Controlling the Power
Tool
Always hold the unit firmly with both hands on the handles while you are working. Wrap your fingers and thumbs around the handles.
Your right hand should grip the rear handle. This also applies to left-handers. With your hands in this position, you can best oppose and absorb the push, pull and kickback forces of your saw without losing control (see section on reactive forces).
Warning!
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!
Keep proper footing and balance at all times. Special care must be taken in slippery conditions (wet ground, snow) and in difficult, overgrown terrain. Watch for hidden obstacles such as tree stumps, roots, rocks, holes and ditches to avoid stumbling. There is increased danger of slipping on freshly debarked logs. For better footing, clear 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, never work on a ladder or any other insecure support. Never hold the machine above shoulder height. Do not overreach.
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MS 291 C-Q
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001BA082 KN
Warning!
Never work in a tree unless you have received specific, professional training for such work, are properly secured (such as tackle and harness system or a lift bucket), have both hands free for operating the chain saw in a cramped environment and have taken proper pre­cautions to avoid injury from falling limbs or branches.
Position the chain saw in such a way that your body is clear of the cutting attachment whenever the engine is running. Stand to the left of cut while bucking.
Never put pressure on the saw when reaching the end of a cut. The pressure may cause the bar and rotating chain to pop out of the cut or kerf, go out of control and strike the operator or some other object. If the rotating chain strikes some other object, a reactive force may cause the moving chain to strike the operator.
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!
Your chain saw is a one-person machine. Do not allow other persons in the general work area, even when start­ing. Stop the engine immediately if you are approached.
Warning!
Even though bystanders should be kept away from the running saw, never work alone. Keep within calling distance of others in case help is needed.
Warning!
As soon as the engine is running, this product gen­erates toxic exhaust fumes containing chemi­cals, such as unburned
hydrocarbons (including benzene) and carbon monoxide, that are known to cause respiratory prob­lems, cancer, birth defects, or other reproductive harm. Some of the gases (e.g. carbon monoxide) may be color­less and odorless. To reduce the risk of serious or fatal injury / illness from inhal­ing toxic fumes, never run the machine indoors or in poorly ventilated locations. If exhaust fumes become concentrated due to insufficient ventilation, clear obstructions from work area to permit proper ventilation before proceeding and / or take frequent breaks to allow fumes to dissipate before they become concentrated.
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 dust and other airborne contaminants, in par­ticular those with a smaller particle size, may cause respiratory or other ill­nesses. This includes wood dust, especially from hardwoods, but also from some softwoods such as Western Red Cedar. Control dust at the source where possible. Use good work prac­tices, such as always cutting with a properly sharpened chain (which pro­duces wood chips rather than fine dust) and operating the unit so that the wind or operating process directs any dust raised by the power tool 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 near the ambient (background) level, the operator and any bystanders should wear a respirator approved by NIOSH / MSHA for the type of dust encountered.
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Warning!
Breathing asbestos dust is dangerous and can cause severe or fatal injury, respiratory illness or cancer. The use and disposal of asbestos-containing products have been strictly regulated by OSHA and the Environmental Protec­tion Agency. If you have any reason to believe that you might be cutting asbes­tos, immediately contact your employer or a local OSHA representative.
Operating Instructions
Warning!
Do not operate your power tool using the starting throttle lock, as you do not have control of the engine speed.
In the event of an emergency, switch off the engine immediately – move the slide control / stop switch to 0 or STOP.
Warning!
Always stop the engine before putting a chain saw down.
Warning!
The saw chain continues to move for a short period after the throttle trigger is released (flywheel effect).
Accelerating the engine while the saw chain is blocked increases the load and will cause the clutch to slip continuously. This may occur if the throttle is depressed for more than a few seconds when the chain is pinched in the cut or the chain brake is engaged. It can result in overheating and damage to important components (e.g. clutch, polymer
housing components) – which can then increase the risk of injury, e.g., from the saw chain moving while the engine is idling.
Warning!
Your chain saw is equipped with a chain catcher. It is designed to reduce the risk of personal injury in the event of a thrown or broken chain. From time to time, the catcher may be damaged or removed. To reduce the risk of personal injury, do not operate a chain saw with a damaged or missing chain catcher.
Warning!
Inspect anti-vibration elements periodi­cally. Replace damaged, broken or excessively worn anti-vibration ele­ments immediately, since they may result in loss of control of the saw. A "sponginess" in the feel of the saw, increased vibration or increased "bot­toming" during normal operation may indicate damage, breakage or exces­sive wear. Anti-vibration elements should always be replaced in sets. If you have any questions as to whether the anti-vibration elements should be replaced, consult your STIHL servicing dealer.
Warning!
Your saw is not designed for prying or shoveling away limbs, roots or other objects. Such use could damage the cutting attachment or AV system.
Warning!
When sawing, make sure that the saw chain does not touch any foreign mate­rials such as rocks, fences, nails and the like. Such objects may be flung off, damage the saw chain or cause the saw to kickback.
Warning!
The muffler and other parts of the engine (e.g. fins of the cylinder, spark plug) become hot during operation and remain hot for a while after stopping the engine. To reduce risk of burns do not touch the muffler and other parts while they are hot.
Warning!
To reduce the risk of fire and burn injury, 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!
Never modify your muffler. A modified or damaged muffler could cause an increase in heat radiation or sparks, thereby increasing the risk of fire and burn injury. You may also permanently damage the engine. Have your muffler serviced and repaired by your STIHL servicing dealer only.
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001BA093 LÄ
001BA035 KN
Catalytic Converter
Warning!
Some STIHL power tools are equipped with a cata­lytic converter, which is designed to reduce the exhaust emissions of the
engine by a chemical process in the muffler. Due to this proc­ess, the muffler does not cool down as rapidly as conventional mufflers when the engine returns to idle or is shut off. To reduce the risk of fire and burn inju­ries, the following specific safety precautions must be observed.
Warning!
Since a muffler with a catalytic converter cools down less rapidly than conven­tional mufflers, 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 materials while it is still hot.
Warning!
An improperly mounted or damaged shroud or a damaged / deformed muffler shell may interfere with the cooling proc­ess of the catalytic converter. To reduce the risk of fire or burn injury, do not con­tinue work with a damaged or improperly mounted cylinder shroud or a damaged / deformed muffler shell.
Your catalytic converter is furnished with screens designed to reduce the risk of fire from the emission of hot particles. Due to the heat from the catalytic reaction, these screens will normally
stay clean and need no service or maintenance. If you experience loss of performance and you suspect a clogged screen, have your muffler maintained by a STIHL servicing dealer.
Reactive Forces including Kickback
Warning!
Reactive forces may occur any time the chain is rotating. Reactive forces can cause serious personal injury.
The powerful force used to cut wood can be reversed and work against the operator. If the rotating chain is suddenly stopped by contact with any solid object such as a log or branch or is pinched, the reactive forces may occur instantly. These reactive forces may result in loss of control, which, in turn, may cause serious or fatal injury. An understanding of the causes of these reactive forces may help you avoid the element of surprise and loss of control. Sudden surprise contributes to accidents.
The most common reactive forces are:
kickback, pushback, pull-in.
Kickback
Kickback may occur when the moving saw chain near the upper quadrant of the bar nose contacts a solid object or is pinched.
The reaction of the cutting force of the chain causes a rotational force on the chain saw in the direction opposite to the chain movement. This may fling the bar up and back in a ligtening fast reaction in an uncontrolled arc mainly in the plane of the bar. Under some cutting circumstances the bar moves towards the operator, who may suffer severe or fatal injury.
Kickback may occur, for example, when the chain near the upper quadrant of the bar nose contacts the wood or is pinched during limbing or when it is incorrectly used to begin a plunge or boring cut.
MS 291 C-Q
13
English
The greater the force of the kickback reaction, the more difficult it becomes for the operator to control the saw. Many factors influence the occurrence and force of the kickback reaction. These include chain speed, the speed at which the bar and chain contact the object, the angle of contact, the condition of the chain and other factors.
The type of bar and saw chain you use is an important factor in the occurrence and force of the kickback reaction. Some STIHL bar and chain types are designed to reduce kickback forces. STIHL recommends the use of reduced kickback bars and low kickback chains.
ANSI B 175.1-2000 chain saw kickback standard
§ 5.11 of ANSI standard B 175.1-2000, sets certain performance and design criteria related to chain saw kickback.
To comply with § 5.11 of ANSI B 175.1-2000:
a) Saws with a displacement of less
than 3.8 cubic inches (62 cm³)
must, in their original condition,
meet a 45° computer derived kickback angle when equipped with certain cutting attachments,
and must be equipped with at least
two devices to reduce the risk of kickback injury, such as a chain brake, low kickback chain, reduced kickback bar, etc.
b) Saws with a displacement of
3.8 cubic inches (62 cm
3
) and
above
must be equipped with at least one
device designed to reduce the risk of kickback injury such as a chain brake, low kickback chain, reduced kickback bar, etc.
The computer derived angles for saws below 3.8 cubic inches (62 cm³) displacement are measured by applying a computer program to test results from a kickback test machine.
Warning!
The computer derived angles of § 5.11 of ANSI B 175.1-2000 may bear no rela­tionship to actual kickback bar rotation angles that may occur in real life cutting situations.
In addition, features designed to reduce kickback injuries may lose some of their effectiveness when they are no longer in their original condition, especially if they have been improperly maintained. Compliance with § 5.11 of ANSI B 175.1-2000 does not automatically mean that in a real life kickback the bar and chain will rotate at most 45°.
Warning!
In order for powerheads below 3.8 cubic inches (62 cm³) displacement to comply with the computed kickback angle requirements of § 5.11 of ANSI B 175.1-2000 use only the following cut­ting attachments:
bar and chain combinations listed
as complying in the "Specifications" section of the instruction manual or
other replacement bar and chain
combinations marked in accordance with the standard for use on the powerhead or
replacement chain designated "low
kickback saw chain."
See the section on "Low kickback saw chain and reduced kickback bars."
Devices for Reducing the Risk of Kickback Injury
STIHL recommends the use of the STIHL Quickstop chain brake on your powerhead with green labeled reduced kickback bars and low kickback chains.
Warning!
To reduce the risk of injury, never use a saw if the chain brake does not function properly. Take the saw to your local STIHL servicing dealer. Do not use the saw until the problem has been rectified.
STIHL Quickstop Chain Brake
STIHL has developed a chain stopping system designed to reduce the risk of injury in certain kickback situations. It is called a Quickstop chain brake.
14
MS 291 C-Q
English
001BA174 KN
When a kickback occurs, the guide bar may rotate around the front handle. If the cutting position is such that the operator’s left hand is gripping the front handle behind the hand guard, and if the left hand rotates around the front handle and makes a sufficiently forceful contact with the front hand guard, which is the Quickstop activating lever, this contact will activate a properly maintained Quickstop chain brake.
All STIHL chain saws are now equipped with a Quickstop chain brake that can be activated by inertia. If the forces of an occurring kickback are sufficiently high, the hand guard is accelerated towards the bar nose even without hand contact.
On models equipped with a STIHL Quickstop Plus chain brake system, the throttle trigger and the throttle trigger lockout on the rear handle act as a third means of activation. See the chapter entitled "Chain Brake" of your instruction manual.
Warning!
Never operate your chain saw without a front hand guard. In a kickback situation this guard helps protect your left hand and other parts of your body. In addition, removal of the hand guard on a saw equipped with a Quickstop chain brake will deactivate the chain brake.
Warning!
No Quickstop or other chain brake device prevents kickback. These devices are designed to reduce the risk of kickback injury, if activated, in certain kickback situations. In order for the Quickstop to reduce the risk of kickback injury, it must be properly maintained and in good working order. See the chapter of your instruction manual enti­tled "Chain Brake" and the section "Maintenance, Repair and Storing" at the end of these Safety Precautions. In addition, there must be enough distance between the bar and the operator to ensure that the Quickstop has sufficient time to activate and stop the chain before potential contact with the operator.
Warning!
An improperly maintained chain brake may increase the time needed to stop the chain after activation, or may not activate at all.
Warning!
Never run the chain saw above idle speed for more than 3 seconds when the chain brake is engaged or when the chain is pinched or otherwise caught in the cut. Clutch slippage can cause excessive heat, leading to severe dam­age of the motor housing, clutch and oiler component and may interfere with the operation of the chain brake. If clutch slippage in excess of 3 seconds has occurred, allow the motor housing to cool before proceeding and check the operation of your chain brake as described in the chapter entitled "Chain Brake" of your instruction manual. Also make sure that the chain is not turning at idle speed (see above at "Important Adjustments").
Low Kickback Saw Chain and Reduced Kickback Bars
STIHL offers a variety of bars and chains. STIHL reduced kickback bars and low kickback chains are designed to reduce the risk of kickback injury. Other chains are designed to obtain higher cutting efficiency or sharpening ease but may result in higher kickback tendency.
STIHL has developed a color code system to help you identify the STIHL reduced kickback bars and low kickback chains. Cutting attachments with green warning decals or green labels on the packaging are designed to reduce the risk of kickback injury. The matching of green decaled powerheads under
3.8 cubic inches (62 cm³) displacement with green labeled bars and green labeled chains gives compliance with the computed kickback angle requirements of ANSI B 175.1-2000
MS 291 C-Q
15
English
when the products are in their original condition. Products with yellow decals or labels are for users with extraordinary cutting needs and experience and specialized training for dealing with kickback.
STIHL recommends the use of its green labeled reduced kickback bars, green labeled low kickback chains and a STIHL Quickstop chain brake for both experienced and inexperienced chain saw users.
Please ask your STIHL dealer to properly match your powerhead with the appropriate bar / chain combination to reduce the risk of kickback injury. Green labeled bars and chains are recommended for all powerheads.
Warning!
Use of other, non-listed bar / chain com­binations may increase kickback forces and the risk of kickback injury. New bar / chain combinations may be developed after publication of this literature, which will, in combination with certain power­heads, comply with § 5.11 of ANSI B 175.1-2000. Check with your STIHL dealer for such combinations.
Warning!
Reduced kickback bars and low kick­back chains do not prevent kickback, but they are designed to reduce the risk of kickback injury. They are available from your STIHL dealer.
Warning!
Even if your saw is equipped with a Quickstop, a reduced kickback bar and / or low kickback chain, this does not eliminate the risk of injury by kickback. Therefore, always observe all safety precautions to avoid kickback situations.
Low Kickback Chain
Some types of saw chains have specially designed components to reduce the force of nose contact kickback. STIHL has developed low kickback chain for your powerhead.
"Low kickback saw chain" is a chain which has met the kickback performance requirements of § 5.11.2.4 of ANSI B 175.1-2000 (Gasoline­Powered Chain Saws-Safety Requirements) when tested in its original condition on a selected representative sample of chain saws below 3.8 cubic inches (62 cm³) displacement specified in ANSI B 175.1-2000.
Warning!
There are potential powerhead and bar combinations with which low kickback saw chains can be used which have not been specifically certified to comply with the 45° computer derived kickback angle of § 5.11 of ANSI B 175.1-2000. Some low kickback chains have not been tested with all powerhead and bar combinations.
Warning!
A dull or improperly sharpened chain may reduce or negate the effects of the design features intended to reduce kick­back energy. Improper lowering or sharpening of the depth gauges or shaping of the cutters may increase the chance and the potential energy of a kickback. Always cut with a properly sharpened chain.
Reduced Kickback Bars
STIHL green labeled reduced kickback bars are designed to reduce the risk of kickback injury when used with STIHL green labeled low kickback chains.
Warning!
When used with other, more aggressive chains, these bars may be less effective in reducing kickback.
Warning!
For a properly balanced saw and in order to comply with § 5.12.1 of ANSI B 175.1-2000, use only bar lengths listed in the specifications chapter of the instruction manual for your chain saw powerhead.
16
MS 291 C-Q
English
001BA037 KN
A
001BA038 KN
B
Bow Guides
Warning!
Do not mount a bow guide on any STIHL chain saw. Any chain saw equipped with a bow guide is potentially very dangerous. The risk of kickback is increased with a bow guide because of the increased kickback contact area. Low kickback chain will not significantly reduce the risk of kickback injury when used on a bow guide.
To Avoid Kickback
The best protection from personal injury that may result from kickback is to avoid kickback situations:
1. Hold the chain saw firmly with both
hands and maintain a secure grip. Do not let go.
2. Be aware of the location of the guide
bar nose at all times.
3. Never let the nose of the guide bar
contact any object. Do not cut limbs with the nose of the guide bar. Be especially careful near wire fences and when cutting small, tough limbs, small size brush and saplings which may easily catch the chain.
4. Do not overreach.
5. Do not cut above shoulder height.
6. Begin cutting and continue at full
throttle.
7. Cut only one log at a time. 8- Use extreme caution when
reentering a previous cut.
9. Do not attempt to plunge cut if you
are not experienced with these cutting techniques.
10. Be alert for shifting of the log or
other forces that may cause the cut to close and pinch the chain.
11. Maintain saw chain properly. Cut
with a correctly sharpened, properly tensioned chain at all times.
12. Stand to the side of the cutting path
of the chain saw.
A = Pull-in
Pull-in occurs when the chain on the bottom of the bar is suddenly stopped when it is pinched, caught or encounters a foreign object in the wood. The reaction of the chain pulls the saw forward and may cause the operator to lose control.
Pull-in frequently occurs when the bumper spike of the saw is not held securely against the tree or limb and when the chain is not rotating at full speed before it contacts the wood.
Warning!
Use extreme caution when cutting small size brush and saplings which may eas­ily catch the chain, be whipped towards you or pull you off balance.
To Avoid Pull-in
1. Always start a cut with the chain
rotating at full speed and the bumper spike in contact with the wood.
2. The risk of pull-in may also be
reduced by using wedges to open the kerf or cut.
B = Pushback
Pushback occurs when the chain on the top of the bar is suddenly stopped when it is pinched, caught or encounters a foreign object in the wood. The reaction of the chain may drive the saw rapidely straight back toward the operator and may cause loss of saw control. Pushback frequently occurs when the top of the bar is used for cutting.
To Avoid Pushback
1. Be alert to forces or situations that
may cause material to pinch the top of the chain.
2. Do not cut more than one log at a
time.
3. Do not twist the saw when
withdrawing the bar from a plunge cut or underbuck cut because the chain can pinch.
MS 291 C-Q
17
English
001BA088 LÄ
2
/
1
2
1 1
/
1
2
B
001BA040 KN
A
45°
45°
B
Cutting Techniques Felling
Felling is cutting down a tree.
Before felling a tree, consider carefully all conditions which may affect the direction of fall.
Warning!
There are a number of factors that may affect and change the intended direction of fall, e.g. wind direction and speed, lean of tree, surrounding trees and obstacles, sloping ground, one-sided limb structure, wood structure, decay, snow load, etc. To reduce the risk of severe or fatal injury to yourself or oth­ers, look for these conditions prior to beginning the cut, and be alert for a change in direction while the tree is falling.
Warning!
Always observe the general condition of the tree. Inexperienced users should never attempt to cut trees which are decayed or rotted inside or which are leaning or otherwise under tension. There is an increased risk that such trees could snap or split while being cut and cause serious or fatal injury to the operator or bystanders. Also look for broken or dead branches which could vibrate loose and fall on the operator. When felling on a slope, the operator should stand on the uphill side if possible.
Felling Instructions
When felling, maintain a distance of at least 2 1/2 tree lengths from the nearest person.
When felling in the vicinity of roads, railways and power lines, etc., take extra precautions. Inform the police, utility company or railway authority before beginning to cut.
Warning!
The noise of your engine may drown any warning call.
Escape Path
First clear the tree base and work area from interfering limbs and brush and clean its lower portion with an ax.
Then, establish two paths of escape (B) and remove all obstacles. These paths should be generally opposite to the planned direction of the fall of the tree (A) and about at a 45° angle. Place all tools and equipment a safe distance away from the tree, but not on the escape paths.
18
MS 291 C-Q
English
001BA146 KN
001BA153 KN
001BA143 KN
C
C
Buttress Roots
If the tree has large buttress roots, cut into the largest buttress vertically first (horizontally next) and remove the resulting piece.
Gunning Sight
When making the felling notch, use the gunning sight on the shroud and housing to check the desired direction of fall:
Position the saw so that the gunning sight points exactly in the direction you want the tree to fall.
Conventional Cut
Felling notch (C) – determines the direction of the fall
For a conventional cut: N Properly place felling notch
perpendicular to the line of fall, close to the ground.
N Cut down at app. 45° angle to a
depth of about 1/5 to 1/4 of the trunk diameter.
N Make second cut horizontal. N Remove resulting 45° piece.
Open-face technique
Felling notch (C) – determines the direction of the fall
For an open-face cut: N Properly place felling notch
perpendicular to the line of fall, close to the ground.
N Cut down at app. 50° angle to a
depth of app.1/5 to 1/4 of the trunk diameter.
N Make second cut from below at app.
40° angle.
N Remove resulting 90° piece.
MS 291 C-Q
19
English
001BA150 KN
001BA144 KN
D
D
001BA145 KN
E
E
Making Sapwood Cuts
N For medium sized or larger trees
make cuts at both sides of the trunk, at same height as subsequent felling cut
N Cut to no more than width of guide
bar.
This is especially important in softwood in summer – it helps prevent sapwood splintering when the tree falls.
D = Felling Cut
Conventional and open-face technique: N Begin 1 to 2 inches (2.5 to 5 cm)
higher than center of felling notch.
N Cut horizontally towards the felling
notch.
N Leave approx. 1/10 of diameter
uncut. This is the hinge.
N Do not cut through the hinge – you
could lose control of the direction of the fall.
Drive wedges into the felling cut where necessary to control the fall.
E = Hinge
N Helps control the falling tree. N Do not cut through the hinge – you
could lose control of the direction of the fall.
20
Warning!
If the tip of the bar contacts a wedge, it may cause kickback. Wedges should be of wood or plastic – never steel, which can damage the chain.
MS 291 C-Q
English
001BA147 KN
001BA148 KN
1
4
2
Felling Cut for Small Diameter Trees: Simple Fan Cut
Engage the bumper spikes of the chain saw directly behind the location of the intended hinge and pivot the saw around this point only as far as the hinge. The bumper spike rolls against the trunk.
Felling Cut for Large Diameter Trees
Warning!
Felling a tree that has a diameter greater than the length of the guide bar requires use of either the sectioning fell­ing cut or plunge-cut method. These methods are extremely dangerous because they involve the use of the nose of the guide bar and can result in kickback. Only properly trained profes­sionals should attempt these techniques.
Sectioning Method
For the sectioning method make the first part of the felling cut with the guide bar fanning in toward the hinge. Then, using the bumper spike as a pivot, reposition the saw for the next cut.
Avoid repositioning the saw more than necessary. When repositioning for the next cut, keep the guide bar fully engaged in the kerf to keep the felling cut straight. If the saw begins to pinch, insert a wedge to open the cut. On the last cut, do not cut the hinge.
Plunge-cut Method
Timber having a diameter more than twice the length of the guide bar requires the use of the plunge-cut method before making the felling cut.
First, cut a large, wide felling notch. Make a plunge cut in the center of the notch.
MS 291 C-Q
21
English
001BA033 KN
The plunge cut is made with the guide bar nose. Begin the plunge cut by applying the lower portion of the guide bar nose to the tree at an angle. Cut until the depth of the kerf is about the same as the width of the guide bar. Next, align the saw in the direction in which the recess is to be cut.
With the saw at full throttle, insert the guide bar in the trunk.
Enlarge the plunge cut as shown in the illustration.
If you are inexperienced with a chain saw, plunge-cutting should not be attempted. Seek the help of a professional.
Warning!
In order to reduce the risk of personal injury, never stand directly behind the tree when it is about to fall, since part of the trunk may split and come back towards the operator (barber-chairing), or the tree may jump backwards off the stump. Always keep to the side of the falling tree. When the tree starts to fall, withdraw the bar, shut off the engine and walk away on the preplanned escape path. Watch out for falling limbs.
Warning!
Be extremely careful with partially fallen trees which are poorly supported. When the tree hangs or for some other reason does not fall completely, set the saw aside and pull the tree down with a cable winch, block and tackle or tractor. If you try to cut it down with your saw, you may be injured.
Limbing
Limbing is removing the branches from a fallen tree.
Do not stand on a log while limbing it – you may slip or the log may roll.
Start limbing by leaving the lower limbs to support the log off the ground. When underbucking freely hanging limbs, a pinch may result or the limb may fall, causing loss of control. If a pinch occurs, stop the engine and remove the saw by lifting the limb.
Warning!
Be extremely cautious when cutting limbs or logs under tension (spring poles). The limbs or logs could spring back toward the operator and cause loss of control of the saw and severe or fatal injury to the operator.
Bucking
Warning!
There is an extreme danger of kick­back at this point. Extra caution must be taken to maintain control of the saw. To make the felling cut, follow the sectioning method described previously.
22
Warning!
There is an extreme danger of kickback during the limbing operation. Do not work with the nose of the bar. Be extremely cautious and avoid contact­ing the log or other limbs with the nose of the guide bar.
Bucking is cutting a log into sections.
MS 291 C-Q
Warning!
001BA051 LÄ
1
001BA151 KN
2
1
001BA152 KN
2
When bucking, do not stand on the log. Make sure the log will not roll downhill. If on a slope, stand on the uphill side of the log. Watch out for rolling logs.
Cut only one log at a time.
Shattered wood should be cut very carefully. Sharp slivers of wood may be caught and flung in the direction of the operator of the saw.
English
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 parts for maintenance and repair. Use of 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 refer to the maintenance chart in this manual.
When cutting small logs, place log through "V" – shaped supports on top of a sawhorse. Never permit another person to hold the log. Never hold the log with your leg or foot.
Logs under strain:
Risk of pinching! Always start relieving cut (1) at compression side.Then make bucking cut (2) at tension side. If the saw pinches, stop the engine and remove it from the log.
Only properly trained professionals should work in an area where the logs, limbs and roots are tangled. Working in "blow down" areas is extremely hazardous. Drag the logs into a clear area before cutting. Pull out exposed and cleared logs first.
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
Warning!
Always stop the engine and make sure that the cutting tool is stopped before doing any maintenance or repair work or cleaning the power tool.
Warning!
Do not attempt any maintenance or repair work not described in your instruction manual. Have such work per­formed by your STIHL servicing dealer only. For example, if improper tools are used to remove the flywheel or if an improper tool is used to hold the fly­wheel in order to remove the clutch, structural damage to the flywheel could occur and could subsequently cause the flywheel to burst.
Wear gloves when handling or performing maintenance on saw chains.
MS 291 C-Q
23
English
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 plug terminal of the proper size. (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 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 plug or with a removed spark plug, since uncontained sparking may cause a fire.
Warning!
Do not operate your chain saw if the muffler is damaged, missing or modi­fied. An improperly maintained muffler will increase the risk of fire and hearing loss.
If your muffler was equipped with a spark-arresting screen to reduce the risk of fire, never operate your saw if the screen is missing or damaged. Remember that the risk of forest fires is greater in hot or dry weather.
Keep the chain, bar and sprocket clean; replace worn sprockets or chains. Keep the chain sharp. You can spot a dull chain when easy-to-cut wood becomes hard to cut and burn marks appear on the wood. Keep the chain at proper tension.
Tighten all nuts, bolts and screws except the carburetor adjustment screws after each use.
Warning!
In order for the chain brake on your STIHL chain saw to properly perform its function of reducing the risk of kickback and other injuries, it must be properly maintained. Like an automobile brake, a chain saw chain brake incurs wear each time it is engaged.
The amount of wear will vary depending upon usage, conditions under which the saw is used and other factors. Excessive wear will reduce the effectiveness of the chain brake and can render it inoperable.
For the proper and effective operation of the chain brake, the brake band and clutch drum must be kept free of dirt, grease and other foreign matter which may reduce friction of the band on the drum.
For these reasons, each STIHL chain saw should be returned to trained personnel such as your STIHL servicing dealer for periodic inspection and servicing of the brake system according to the following schedule:
Heavy usage – every three months, Moderate usage – twice a year, Occasional usage – annually.
The chain saw should also be returned immediately for maintenance whenever the brake system cannot be thoroughly cleaned or there is a change in its operating characteristics.
For any maintenance of the emission control system please refer to the maintenance chart and to the limited warranty statement near the end of the instruction manual.
Do not clean your machine with a pressure washer. The solid jet of water may damage parts of the machine.
Store chain saw in a dry place and away from children. Before storing for longer than a few days, always empty the fuel tank (see chapter "Storing the Machine" in the instruction manual).
24
MS 291 C-Q
English
001BA191 KN
1
2
3
a
t = a : 2
2
1
133BA026 KN
3
4
133BA027 KN
5
133BA028 KN
4
8
7
6
133BA029 KN
Cutting Attachment
Mounting the Bar and
Mounting the tensioning gear
Chain (quick chain
STIHL is the only manufacturer in the industry to produce its own chain saws, guide bars, saw chains and chain sprockets.
A cutting attachment consists of the saw chain, guide bar and chain sprocket.
The cutting attachment that comes standard is designed to exactly match the chain saw.
The pitch (t) of the saw chain (1),
chain sprocket and the nose sprocket of the Rollomatic guide bar must match.
The drive link gauge (2) of the saw
chain (1) must match the groove width of the guide bar (3).
If non-matching components are used, the cutting attachment may be damaged beyond repair after a short period of operation.
MS 291 C-Q
tensioner)
Removing the chain sprocket cover
N Remove and reverse tensioning
gear (4)
N Unscrew nut (5)
N Swing grip (1) into position until it
engages
N Turn the wing nut (2) to the left until
it hangs loosely in the chain sprocket cover (3)
N Remove chain sprocket cover
N Position tensioning gear (4) and
guide bar (6) relative to one another so that the headless pin (7) protrudes through the upper hole of the guide bar and the short guide peg (8) protrudes into the lower hole of the guide bar
25
English
5
133BA030 KN
133BA032 KN
9
4
133BA031 KN
11
10
133BA033 KN
133BA034 KN
Fitting the saw chain
N Fit the nut (5) and screw it by hand
onto the headless pin as far as it will go
Releasing the chain brake
N Release the chain brake by pushing
the hand guard (9) against the front handle
N Place the saw chain on the chain
sprocket (10)
N Position guide bar – the long middle
mounting stud (11) protrudes through the hole in the tensioning gear – the heads of the two short mounting studs protrude into the oblong hole of the guide bar
Put on protective gloves – risk of injury by the sharp cutters
N Fit the saw chain – starting at the
nose of the guide bar – pay attention to the position of the tensioning gear and the cutting edges
N Turn tensioning gear (4) to the right
as far as possible
N Turn the guide bar so that the
tensioning gear faces the user
26
N Press the throttle trigger lockout to
release the chain brake
N Guide the drive link into the bar
groove (see arrow) and turn the tensioning gear to the left as far as possible
MS 291 C-Q
English
11
133BA035 KN
13
12
133BA036 KN
1
2
001BA112 KN
143BA007 KN
N Fit chain sprocket cover, ensuring
that the mounting stud (11) protrudes into the center of the wing nut
When fitting the chain sprocket cover, the teeth of the adjusting wheel and the tensioning gear must mesh; if necessary,
N turn the adjusting wheel (12) a little
until the chain sprocket cover can be slid completely against the engine housing
N Swing grip (13) into position until it
engages
N Fit wing nut and tighten lightly N Go to chapter "Tensioning the saw
chain"
Tensioning the Saw Chain (quick chain tensioner)
Retensioning during cutting work:
N Shut off the engine. N Pull out the hinged clip and loosen
the wingnut.
N Turn the adjusting wheel (1)
clockwise as far as stop.
N Tighten down the wingnut (2) firmly
by hand.
N Fold down the hinged clip. N Go to "Tensioning the Saw Chain"
A new chain has to be retensioned more often than one that has been in use for some time.
N Check chain tension frequently –
see chapter on "Operating Instructions".
Checking Chain Tension
N Shut off the engine. N Wear work gloves to protect your
hands.
N Press down the trigger lockout to
disengage the Quickstop Plus chain brake.
N The chain must fit snugly against
the underside of the bar and it must still be possible to pull the chain along the bar by hand when the chain brake is released.
N If necessary, retension the chain.
A new chain has to be retensioned more often than one that has been in use for some time.
N Check chain tension frequently –
see chapter on "Operating Instructions".
MS 291 C-Q
27
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 quality two-stroke air cooled engine oil.
Use mid-grade unleaded gasoline with a minimum octane rating of 89 (R+M/2). If the octane rating of the mid-grade gasoline in your area is lower, use premium unleaded fuel.
Fuel with a lower octane rating may increase engine temperatures. This, in turn, increases the risk of piston seizure and damage to the engine.
The chemical composition of the fuel is also important. Some fuel additives not only detrimentally affect elastomers (carburetor diaphragms, oil seals, fuel lines, etc.), but magnesium castings and catalytic converters as well. This could cause running problems or even damage the engine. For this reason STIHL recommends that you use only 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.
Engines equipped with M-Tronic can be run on gasoline with an ethanol content of up to 25% (E25).
Use only STIHL two-stroke engine oil or equivalent high-quality two-stroke engine oils that are designed for use only in air cooled two-cycle engines.
We recommend STIHL HP Ultra 2-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 mix oils that state they are for use in both water cooled and air cooled engines (e.g., outboard motors, snowmobiles, chain saws, mopeds, etc.).
Take care when handling gasoline. Avoid direct contact with the skin and avoid inhaling fuel vapor. When filling at the pump, first remove the canister from your vehicle and place the canister on the ground before filling. Do not fill fuel canisters that are sitting in or on a vehicle.
The canister should be kept tightly closed in order to avoid any moisture getting into the mixture.
The machine‘s fuel tank and the canister in which fuel mix is stored should be cleaned as necessary.
Fuel mix ages
Only mix sufficient fuel for a few days work, not to exceed 3 months of storage. Store in approved fuel-canisters only. When mixing, pour oil into the canister first, and then add gasoline. Close the canister and shake it vigorously by hand to ensure proper mixing of the oil with the fuel.
Gaso­line
US gal. US fl.oz
12.6 2 1/2 6.4 5 12.8
Dispose of empty mixing-oil canisters only at authorized disposal locations.
Oil (STIHL 50:1 or equiva­lent high-quality oils)
28
MS 291 C-Q
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