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STIHL MS 231, 251

1. Never attempt to modify the controls or safety devices in any way Keep the handles dry and clean free from oil and dirt for safe control of the saw Make sure there is sufficient fuel and chain oil in the tanks To reduce the risk of personal injury do not operate your saw if it is damaged or not properly assembled Starting the chain saw Always work on a level surface Ensure a firm and secure footing Hold the machine securely the chain must not touch any objects or the floor danger of injury due to the rotating saw chain MS 231 MS 231 C MS 251 MS 251 C Your chain saw is a one person saw Do not allow other persons to be in the working area not even while starting Do not start the chain saw if the chain is in a cut Move at least 3 meters away from the place where the machine was refuelled and never start the motor in enclosed spaces Lock the chain with the chain brake before starting risk of injury due to rotating chain Do not drop start the engine start as described in the Instruction Manual During operation Ensure you always have a firm and safe footing Take special care when the bark is wet danger of slipping Always hold the chain saw firmly with both hands Right hand on the rear handle even if you are left handed To ensure reliable control wrap your thumbs tightly around the handlebar and handle In the event of impending danger or in an em
2. a universal tool for checking sharpening and side plate angles depth gauge setting and tooth length as well as cleaning grooves and oil inlet holes Proper sharpening Select sharpening tools in accordance with chain pitch Clamp guide bar if necessary Block saw chain push the hand guard forward To advance the saw chain pull the hand guard toward the handlebar The chain brake is disengaged With the Quickstop Super chain brake system additionally press the throttle trigger lockout Sharpen frequently removing little material two or three strokes of the file are usually sufficient for simple resharpening 689BA018 KN zZ x o x lt a D e Guide the file horizontally at a right angle to the side surface of the guide bar in accordance with the specified angle according to the MS 231 MS 231 C MS 251 MS 251 C markings on the file holder rest the file holder on the tooth head and the depth gauge e File only from the inside outward The file only sharpens on the forward stroke lift the file on the backstroke Do not file tie straps and drive links Rotate the file a little periodically in order to avoid uneven wear Toremove file burr use a piece of hardwood e Check angle with file gauge All cutters must be equally long With varying cutter lengths the cutter heights also vary and cause rough running of the saw chain and chain breakage
3. 6 0 mm Rapid 0 404 7 0 mm If the groove is not at least this deep Replace guide bar Otherwise the drive links will grind against the base of the groove the bottoms of the cutters and the tie straps will not lie against the bar 34 Shroud Remove shroud Move the Master Control Lever to the stop position 0 Push the front hand guard forwards the saw chain is blocked zZ x e e S lt a KR N Loosen screws 1 Remove the shroud 2 Refitting the shroud Refit the shroud and tighten the screws Air Filter System The air filter system can be adapted to suit different operating conditions by installing different filters Changing the filter is quick and simple Fleece filter 5902BA009 KN Fleece filter for normal operating conditions and dry work areas HD2 filter z x o 3 S lt ao A S D ire e HD2 filter black filter frame pleated filter material for extreme wintry conditions e g powder or drifting snow or very dusty work areas MS 231 MS 231 C MS 251 MS 251 C Cleaning the Air Filter If there is a noticeable loss of engine power Remove the shroud see Shroud Removing the air filter Clean away loose dirt from around the filter Blvorice Do not use tools to remove and install the air filter the air filter could be damaged in the process 3 lt a i Q N e Turn airfilter 1 4
4. Cleaning Clean plastic parts with a cloth Harsh detergents can damage the plastic Clean the dust and dirt off the machine do not use any grease solvents for this purpose Clean the ventilation slots if necessary Do not use a high pressure cleaner to clean the machine The hard jet of water can damage parts of the machine Accessories Only use those tools guide bars chains chain sprockets accessories or technically equivalent components that have been approved by STIHL for this machine If you have any questions in this respect consult a servicing dealer Use only high quality tools and accessories Otherwise there may be a risk of accidents and damage to the machine STIHL recommends the use of genuine STIHL tools guide bars chains chain sprockets and accessories They are specifically designed to match your model and meet your performance requirements Refuelling Petrol is an extremely flammable fuel keep clear of naked flames and fire do not spill any fuel no smoking Switch off the engine before refuelling Never refuel the machine while the engine is still hot the fuel may spill over risk of fire Open the fuel filler cap carefully so that any excess pressure is relieved gradually and fuel does not splash out The machine may only be refuelled in a well ventilated place Clean the machine immediately if fuel is spilled Do not spill fuel over your clothing contami
5. Sloping ground Neighboring trees Snow load Soundness of tree take special care if trunk is damaged or in case of deadwood dry decayed or rotted wood 11 English 12 z amp fe g S lt a gt S Direction of fall Escape path or retreat path Establish paths of escape for everyone concerned opposite to direction of fall at about 45 Remove all obstacles from escape paths Place all tools and equipment a safe distance away from the tree but not on the escape paths Always keep to the side of the falling tree and only walk away along the preplanned escape path On steep slopes plan escape routes parallel to the slope When walking away along the escape path watch out for falling limbs and watch the top of the tree Preparing work area at base of tree First clear the tree base and work area from interfering limbs and brush to provide a secure footing Clean lower portion of tree base e g with an axe sand stones and other foreign objects will dull the saw chain 2 o ST lt ao 3S Ss Make the vertical cut first then the horizontal but only if the wood is sound Felling Notch Preparing felling notch zZ Ea x N lt a S The felling notch C determines the direction of fall Important Make felling notch at a right angle to the planned direction of fall Cut close to the ground Cut to a depth of ab
6. Tighten the spark plug and press on the spark plug boot firmly e Fit the shroud see Shroud English Rewind Starter To help prolong the wear life of the starter rope observe the following points Pull the starter rope only in the direction specified e Donot pull the rope over the edge of the guide bushing e Do not pull out the rope more than specified e Donot allow the starter grip to snap back guide it back into the housing slowly see chapter on Starting Stopping the Engine Have a damaged starter rope replaced by your dealer before it breaks completely STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer 37 English Storing the Machine For periods of 3 months or longer 38 Drain and clean the fuel tank in a well ventilated area Dispose of fuel properly in accordance with local environmental requirements Run the engine until the carburetor is dry this helps prevent the carburetor diaphragms sticking together Remove the saw chain and guide bar clean them and spray with corrosion inhibiting oil Thoroughly clean the machine pay special attention to the cylinder fins and air filter If you use a biological chain and bar lubricant e g STIHL BioPlus completely fill the chain oil tank Store the machine in a dry high or locked location out of the reach of children and other unauthorized pe
7. e All cutters must be filed down equal to the length of the shortest cutter ideally one should have this done by a servicing dealer using an electric sharpener Depth gauge setting Zz x Fe a S lt a D The depth gauge determines the depth to which the cutter penetrates the wood and thus the chip thickness MS 231 MS 231 C MS 251 MS 251 C a Required distance between depth gauge and cutting edge When cutting softwood outside of the frost season the distance can be increased by up to 0 2 mm 0 008 Chain pitch Depth gauge Distance a Inches mm mm Inches 1 4 P 6 35 0 45 0 018 1 4 6 35 0 65 0 026 3 8 P 9 32 0 65 0 026 0 325 8 25 0 65 0 026 3 8 9 32 0 65 0 026 0 404 10 26 0 80 0 031 Lowering the depth gauges The depth gauge setting is lowered when the cutter is sharpened Check the depth gauge setting after each sharpening English Saw chains with humped drive link 2 upper part of the humped drive link 2 with service mark is lowered at the same time as the depth gauge of the cutter Awarnine The rest of the humped drive link must not be filed otherwise this could increase the tendency of the chain saw to kick back 689BA051 KN Rework the depth gauge so that it is flush with the file gauge 689BA061 KN e Lay the appropriate file gauge 1 for the chain pitch on the saw chain and press it against the c
8. e Engage the spiked bumper behind the holding strap and use it as a pivot avoid repositioning the saw more than necessary The guide bar nose enters the wood 1 before it reaches the hinge hold the saw horizontally and swing it as far as possible Do not cut into the holding strap or hinge e Enlarge felling cut as far as hinge 2 Do not cut into the hinge e Enlarge felling cut as far as holding strap 3 Do not cut into the holding strap MS 231 MS 231 C MS 251 MS 251 C Continue the felling cut on the other side of the trunk Make sure the second cut is at the same English Cut through the holding strap ata downward angle from outside with outstretched arms height as the first cut Engage the spiked bumper behind the hinge and use it as a pivot avoid repositioning the saw more than necessary The guide bar nose enters the wood 4 before it reaches the holding strap hold the saw horizontally and swing it as far as possible Enlarge felling cut as far as hinge 5 Do not cut into the hinge Enlarge felling cut as far as holding strap 6 Do not cut into the holding strap z x N lt ao Q Shout a second warning immediately before the tree falls 17 English Cutting Attachment A cutting attachment consists ofthe saw chain guide bar and chain sprocket The cutting attachment that comes standard is designed to
9. only use replacement parts which have been approved by STIHL for this power tool or are technically identical Only use high quality replacement parts in order to avoid the risk of accidents and damage to the machine STIHL recommends the use of original STIHL replacement parts Original STIHL parts can be identified by the STIHL part number the STIHL logo and the STIHL parts symbol 67 the symbol may appear alone on small parts MS 231 MS 231 C MS 251 MS 251 C Disposal Observe all country specific waste disposal rules and regulations z x N N S lt a Q o STIHL products must not be thrown in the garbage can Take the product accessories and packaging to an approved disposal site for environment friendly recycling Contact your STIHL servicing dealer for the latest information on waste disposal MS 231 MS 231 C MS 251 MS 251 C EC Declaration of Conformity ANDREAS STIHL AG amp Co KG Badstr 115 D 71336 Waiblingen confirms that the product described below Chainsaw STIHL MS 231 MS 231 C MS 231 C BE MS 251 MS 251 C MS 251 C BE 1143 Category Make Model Serial identification Displacement all versions of MS 231 42 6 cm all versions of MS 251 45 6 cm conform to the specifications of Directives 2006 42 EC 2004 108 EC and 2000 14 EC and have been developed and built in compliance with the following standards being in effect at the date of manufacture E
10. 1110 893 4000 0814 252 3356 5605 007 1029 0 404 10 26 5 5 7 32 56057725506 56057504330 1106 893 4000 0814 252 3356 5605 007 1030 1 consisting of file holder with round file taper square file and file gauge 42 MS 231 MS 231 C MS 251 MS 251 C Maintenance and Care English The following maintenance intervals apply to normal usage and operating conditions If your daily gt working time is longer or operating conditions are difficult very dusty work area resin rich wood trop T a ical wood etc shorten the specified intervals accordingly If you only use your power tool z 3 occasionally extend the intervals accordingly x gt D o 2 gt 5 S T Oo Oo s 5 5 g L o T Q ee S 3 2 2 zZ E z S 5 s 82 5 5 5 3 3 8 Q gt on D a a z E Visual inspection condition leaks x x Complete machine Clean x Throttle trigger trigger lockout choke lever stop switch Master Control lever depending on Check operation x x version Check operation x x Chain brake Have checked by servicing dealer x Check x Manual fuel pump if fitted Have repaired by servicing dealer x Check Pickup body filter in fuel tank Clean replace filter element x Replace x x x Fuel tank Clean Chain oil tank Clean Chain lubrication Check x Inspect also check sharpness x x Ch
11. accidents To reduce the risk of fire due to ignition outside the cylinder move the master control level to STOP 0 or before turning the engine over on the starter when the spark plug boot is removed or the spark plug is unscrewed Do not service or store the machine near a naked flame risk of fire due to the fuel Check fuel cap regularly for tightness Use only spark plugs that are in perfect condition and have been approved by STIHL see Specifications MS 231 MS 231 C MS 251 MS 251 C English Check ignition lead insulation in good condition secure connection servicing dealer do not use the machine until the malfunction has been Check that the muffler is in perfect ic working condition Do not use the machine ifthe muffler is damaged or missing risk of fire damage to hearing Never touch a hot muffler risk of burns The condition of the anti vibration elements influences vibration behaviour inspect anti vibration elements periodically Inspect chain catcher replace if damaged Switch off the engine To check the chain tension Toretension the chain To replace the chain For remedying malfunctions Observe sharpening instructions for safe and proper handling always keep the chain and guide bar in flawless condition Keep the chain properly sharpened tensioned and well lubricated Change chain guide bar and chain sprocket in due time Regularly ch
12. engine oil preferably STIHL HP HP Super or HP Ultra which are specially formulated for use in STIHL engines HP Ultra guarantees high performance and a long engine life These engine oils are not available in all markets Use only STIHL 50 1 two stroke engine oil for the fuel mix in models with a catalytic converter Mix Ratio STIHL 50 1 two stroke engine oil 50 parts gasoline to 1 part oil MS 231 MS 231 C MS 251 MS 251 C Examples Gasoline STIHL engine oil 50 1 Liters Liters ml 1 0 02 20 5 0 10 100 10 0 20 200 15 0 30 300 20 0 40 400 25 0 50 500 e Use a canister approved for storing fuel Pour oil into canister first then add gasoline and mix thoroughly Storing Fuel Store fuel only in approved safety type fuel canisters in a dry cool and safe location protected from light and the sun Fuel mix ages only mix sufficient fuel for a few weeks work Do not store fuel mix for longer than 30 days Exposure to light the sun low or high temperatures can quickly make the fuel mix unusable STIHL MotoMix may be stored for up to 2 years without any problems e Thoroughly shake the mixture in the canister before fueling your machine Awaenine Pressure may build up in the canister open it carefully e Clean the fuel tank and canister from time to time English Dispose of remaining fuel and cleaning fluid properly in accordance with local regulations and en
13. exactly match the chain saw N lt ao gt 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 18 Chain Scabbard 001BA244 KN Your saw comes standard with a chain scabbard that matches the cutting attachment If guide bars of different lengths are mounted to the saw always use a chain scabbard of the correct length which covers the complete guide bar The length of the matching guide bars is marked on the side of the chain scabbard Mounting the Bar and Chain side chain tensioner Removing the chain sprocket cover 533BA001 KN Unscrew the nut and remove the chain sprocket cover zZ x wo 2 lt ao 5 O Turn the screw 1 counterclockwise until the tensioner slide 2 butts against the left end of the housing slot MS 231 MS 231 C MS 251 MS 251 C Disengage the chain brake 001BA186 KN e Pull the hand guard towards the front handle until there is an audible click the chain brake is disengaged Fitting the chain Zz x ise O lt a oO x d warnine Wear work gloves to protect your hands from the sharp cutters e
14. guide bars Cutting lengths 35 40 45 cm Pitch 325 8 25 mm Groove width 1 6 mm Nose sprocket 11 tooth 3 8 P Rollomatic E guide bars 30 35 40 45 cm 3 8 P 9 32 mm 1 3mm 9 tooth Cutting lengths Pitch Groove width Nose sprocket English 325 chain Rapid Micro 3 26 RM3 Type 3634 Rapid Duro 3 26 RD3 Type 3667 Pitch 325 8 25 mm Drive link gauge 1 6 mm 3 8 P chain Picco Micro 3 63 PM3 Type 3636 Picco Super 3 63 PS3 Type 3616 Picco Duro 3 63 PD3 Type 3612 Pitch 3 8 P 9 32 mm Drive link gauge 1 3 mm Chain sprocket 7 tooth for 325 Max chain velocity to ISO 11681 25 6 m s 6 tooth for 3 8 P Max chain velocity to ISO 11681 24 8 m s As a rule the mean chain velocity in operation is about 20 lower than the maximum chain velocity in accordance with ISO 11681 Contact your STIHL servicing dealer for advice on personal protective equipment Noise and Vibration Data For further details on compliance with Vibration Directive 2002 44 EC see www stihl com vib 47 English Sound pressure level L to ISO 22868 MS 231 103 dB A MS 231 C 103 dB A MS 251 103 dB A MS 251 C 103 dB A Sound power level L to ISO 22868 MS 231 114 dB A MS 231 C 114 dB A MS 251 114 dB A MS 251 C 114 dB A Vibration measurement apy eq to ISO 22867 Handle Handle left right MS 231 3 9 m s 3 9 m s MS 231C 3 9m s 3 9 mis MS 251 3 9 m s 3 9 m s
15. nut Hold the bar nose up Use a screwdriver to turn the tensioning screw 1 clockwise until the chain fits snugly against the underside of the bar While still holding the bar nose up tighten down the nut firmly Go to Checking Chain Tension A new chain has to be retensioned more often than one that has been in use for some time Check chain tension frequently see chapter on Operating Instructions 21 English Tensioning the Saw Chain quick chain tensioner 4 z a 5 S 6 Retensioning during cutting work e Shut off the engine e Pull out the hinged clip and loosen the wingnut e Turn the adjusting wheel 1 clockwise as far as stop Tighten down the wingnut 2 firmly by hand e Fold down the hinged clip Goto Checking Chain Tension Anew chain has to be retensioned more often than one that has been in use for some time Check chain tension frequently see chapter on Operating Instructions 22 Checking Chain Tension x lt ca a Shut off the engine Wear work gloves to protect your hands 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 e f necessary retension the chain A new chain has to be retensioned more often than one that has been in use for some time Check chain tension frequently see
16. side of the trunk Make sure the second cutis at the same height as the first cut 15 English Start felling cut using plunge cut method Enlarge felling cut as far as hinge 4 Do not cut into the hinge Enlarge felling cut as far as stabilizing strap 5 Do not cut into the stabilizing strap Zz x x N lt a o o Insert a felling wedge 6 Shout a second warning immediately before the tree falls 16 Holding the saw with outstretched arms cut through the stabilizing strap horizontally at the same level as the felling cut Felling Cut with Holding Strap Leaner A Small diameter trees Perform this felling cut when the tree diameter is smaller than the length ofthe guide bar zZ x lt ao e f Shout a second warning immediately before the tree falls gt Cut through the holding strap ata downward angle from outside with outstretched arms a 001BA265 KN e Plunge the guide bar into the trunk until it emerges at the other side e Enlarge the felling cut E in direction of hinge 1 Cut horizontally Do not cut into the hinge e Enlarge the felling cut in direction of holding strap 2 Cut horizontally Do not cut into the holding strap MS 231 MS 231 C MS 251 MS 251 C B Large diameter trees 001BA267 KN Perform this felling cut when the tree diameter is greater than the length ofthe guide bar
17. speed engage the chain brake push hand guard toward bar nose and open the throttle wide for no more than 3 seconds the chain must not rotate The hand guard must be free from dirt and move freely Chain brake maintenance The chain brake is subject to normal wear It is necessary to have it serviced and maintained regularly by trained personnel STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer Maintain the following servicing intervals Full time usage every 3 months Part time usage every 6 months Occasional usage every 12 months 27 English Winter Operation me Pre heating carburetor Remove the shroud see Shroud At temperatures below 10 C e Using a screwdriver pry the shutter out of the summer operation position 2 x 8 lt a an N e Place the shutter with the opening in the direction of the chain saw in the position winter operation shutter must audibly snap into place e Fitthe shroud see Shroud 28 Heated air is now drawn in from around the cylinder and circulates around the carburetor this helps prevent carburetor icing At temperatures above 20 C e Ensure that the shutter is always returned to position summer operation otherwise the engine may malfunction due to overheating At temperatures below 10 C e if the chain saw is extremely cold frost form
18. Always contact your local forest authority for information on a possible fire risk zZ oO ised gt lt a 3S If on a slope stand on the uphill side of the log Watch out for rolling logs When working at heights Always use a lift bucket Never work on a ladder or in a tree Never work on an insecure support Do not work above shoulder height Never operate your power tool with one hand Begin cutting with the saw at full throttle and engage the spiked bumper firmly in the wood and then continue cutting Never work without the spiked bumper because the saw may pull you forwards and off balance Always engage the spiked bumper securely in the tree or limb Note when reaching the end of a cut that the saw is no longer supported in the kerf You have to take the full weight of the machine since it might otherwise go out of control When cutting small logs Use a sturdy and stable support sawhorse Never hold the log with your leg or foot Never allow another person to hold the log or help in any other way Limbing Use a low kickback chain Work with the saw supported wherever possible Do not stand on the log while limbing it Do not cut with the bar nose Watch for limbs which are under tension Never cut several limbs at once Lying or standing logs under tension Always make cuts in the correct sequence first at the compression side 1 t
19. Fitthe chain start at the bar nose MS 231 MS 231 C MS 251 MS 251 C 20 So er Sooo me Fit the guide bar over the studs 1 the cutting edges on the top of the bar must point to the right Engage the peg of the tensioner slide in the locating hole 2 place the chain over the sprocket 3 at the same time Turn the tensioning screw 4 clockwise until there is very little chain sag on the underside of the bar and the drive link tangs are engaged in the bar groove Refit the sprocket cover and screw on the nut only fingertight Go to chapter on Tensioning the Saw Chain English Mounting the Bar and Chain quick chain tensioner Removing the chain sprocket cover 2310BA013 KN Swing grip 1 into position until it engages Turn the wing nut 2 to the left until it hangs loosely in the chain sprocket cover 3 Remove chain sprocket cover 3 Mounting the tensioning gear FA amp x gt lt ao D N Remove and reverse tensioning gear 1 19 English Releasing the chain brake e Fitthe saw chain starting at the nose of the guide bar pay attention to the position of the tensioning gear and the cutting edges Turn tensioning gear 1 to the right as far as possible Turn the guide bar so that the tensioning gear faces the user z x ited o lt a D N 001BA186 KN e Pull hand guard towards the front handle until it engages
20. MS 251 C 001BA261 KN Shout a warning before starting the felling cut Start felling cut E using plunge cut method insert full length of guide bar in the trunk e Engage the spiked bumper behind the hinge and use it as a pivot avoid repositioning the saw more than necessary e Enlarge felling cut as far as hinge 1 Do not cut into the hinge e Enlarge felling cut as far as stabilizing strap 2 Do not cut into the stabilizing strap MS 231 MS 231 C MS 251 MS 251 C 001BA273 KN e Inserta felling wedge 3 Shout a second warning immediately before the tree falls Holding the saw with outstretched arms cut through the stabilizing strap horizontally at the same level as the felling cut B Large diameter trees Perform this felling cut when the tree diameter is greater than the length of the guide bar English 001BA263 KN Shout a warning before starting the felling cut Engage the spiked bumper at the required height of the felling cut and use it as a pivot avoid repositioning the saw more than necessary The guide bar nose enters the wood 1 before it reaches the hinge hold the saw horizontally and swing it as far as possible e Enlarge felling cut as far as hinge 2 Do not cut into the hinge e Enlarge felling cut as far as stabilizing strap 3 Do not cut into the stabilizing strap Continue the felling cut on the other
21. MS 251C 3 9m s 3 9 mis The K factor in accordance with Directive 2006 42 EC is 2 5 dB A for the sound pressure level and sound power level the K factor in accordance with Directive 2006 42 EC is 2 0 m s for the vibration measurement REACH REACH is an EC regulation and stands for the Registration Evaluation Authorisation and Restriction of Chemical substances For information on compliance with the REACH regulation EC No 1907 2006 see www stihl com reach 48 Ordering Spare Parts Please enter your saw model serial number as well as the part numbers of the guide bar and saw chain in the spaces provided This will make re ordering simpler The guide bar and saw chain are subject to normal wear and tear When purchasing these parts always quote the saw model the part numbers and names of the parts Model Serial number Guide bar part number Chain part number Maintenance and Repairs Users of this machine may only carry out the maintenance and service work described in this user manual All other repairs must be carried out by a servicing dealer STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer STIHL dealers are regularly given the opportunity to attend training courses and are supplied with the necessary technical information When repairing the machine
22. N ISO 11681 1 EN 55012 EN 61000 6 1 The measured and guaranteed sound power levels were determined according to Directive 2000 14 EC Annex V using the ISO 9207 standard Measured sound power level all versions of MS 231 114 dB A all versions of MS 251 114 dB A English Guaranteed sound power level all versions of MS 231 116 dB A all versions of MS 251 116 dB A The EC type examination was carried out by DPLF Deutsche Pr f und Zertifizierungsstelle f r Land und Forsttechnik NB 0363 Max Eyth Weg 1 D 64823 Gross Umstadt Certification No all versions of MS 231 all versions of MS 251 Technical documents deposited at ANDREAS STIHL AG amp Co KG Produktzulassung Product Licensing K EG 2010 5603 K EG 2010 5605 The year of manufacture and serial number are applied to the product Waiblingen 20 08 2014 ANDREAS STIHL AG amp Co KG PP Wera Ly Ss Thomas Elsner Director Group Product Management CE 49 0458 737 0121 B englisch 458 737 0121 B
23. STIHL STIHL MS 231 251 instruction Manual Original Instruction Manual Printed on chlorine free paper ANDREAS STIHL AG amp Co KG 2014 0458 737 0121 B VA3 K14 0000006607_004_GB Printing inks contain vegetable oils paper can be recycled Contents Guide to Using this Manual 2 Safety Precautions 3 Reactive Forces 8 Working Techniques 9 Cutting Attachment 18 Mounting the Bar and Chain side chain tensioner 18 Mounting the Bar and Chain quick chain tensioner 19 Tensioning the Saw Chain side chain tensioner 21 Tensioning the Saw Chain quick chain tensioner 22 Checking Chain Tension 22 Fuel 22 Fueling 24 Chain Lubricant 25 Filling Chain Oil Tank 26 Checking Chain Lubrication 26 Chain Brake 27 Winter Operation 28 Starting Stopping the Engine 28 Operating Instructions 32 Taking Care of the Guide Bar 33 Shroud 34 Air Filter System 34 Cleaning the Air Filter 35 Adjusting the Carburetor 35 Spark Plug 36 Rewind Starter 37 Storing the Machine 38 STIHL MS 231 MS 231 C MS 251 MS 251 C Checking and Replacing the Chain Sprocket Maintaining and Sharpening the Saw Chain Maintenance and Care Minimize Wear and Avoid Damage Main Parts Specifications Ordering Spare Parts Maintenance and Repairs Disposal EC Declaration of Conformity 38 39 43 46 47 48 48 49 49 English Dear Customer Thank you for choosing a quality engineered STIHL product It has been built using m
24. The plunge cutting sight and the top and bottom of the guide bar are parallel When making the plunge cut the sight helps keep the hinge horizontal i e the same thickness all round To do this hold the plunge cutting sight parallel to the chord of the felling notch Felling wedges Make use of wedges as soon as possible i e providing they do not interfere with cutting Drive wedge into felling cut with a suitable tool Use only aluminum or plastic wedges never steel Steel wedges can seriously damage the saw chain and cause dangerous kickback Select felling wedges that suit the diameter of the tree and width of the kerf felling cut E Contact your STIHL dealer for advice on selecting the right felling wedge length width and height Choosing Right Felling Cut The criteria for choosing the right felling cut are the same as those for determining the direction of fall and the escape path There are many different variations of these characteristics Only the two most common characteristics are described in this manual z x o N lt ao 2 i AW Din alone tein ne ben N a Left Normal tree vertical trunk with uniform tree crown Leaner tree crown leans in direction of fall Right Felling Cut with Stabilizing Strap Normal Tree A Small diameter trees Perform this felling cut when the tree diameter is smaller than the length of the guide bar MS 231 MS 231 C MS 251
25. ain Check chain tension x Sharpen x Check wear damage x Clean and turn over x Guide bar Deburr x Replace x x Chain sprocket Check x Clean x x Air filter Replace x MS 231 MS 231 C MS 251 MS 251 C 43 English The following maintenance intervals apply to normal usage and operating conditions If your daily oe working time is longer or operating conditions are difficult very dusty work area resin rich wood trop E a ical wood etc shorten the specified intervals accordingly If you only use your power tool 2 3 occasionally extend the intervals accordingly x Z D S gt 3 gt 5 S c E Oo Oo 5 s e 3 8 B Q G A N o D amp p gt 5 gle le el 8 gt 3 585 3 si2e 2 3 82 2 S a z E o Check x x Antivibration elements Have replaced by servicing dealer x Air inlet on fan housing Clean x x Cylinder fins Clean x x x Check idle adjustment chain must not rotate x x Carburetor Adjust idle speed if necessary have saw serv x iced or repaired by dealer Readjust electrode gap x Spark plug Replace after every 100 hours of operation All accessible screws and nuts not adjusting Retighten X screws Check x Chain catcher Replace x Exhaust port Decoke after first 139 hours of operation then X every 150 hours of operation Safety labels Replace x 1 STIHL recommends a STIHL ser
26. ation after starting bring the engine up to operating temperature at increased idle speed disengage chain brake In case of erratic idling behavior or poor acceleration Turn the low speed screw L 1 4 turn counterclockwise Whenever the low speed screw L has been adjusted it is usually also necessary to adjust the idle speed adjusting screw LA see Setting the carburetor Air filter system e Retrofit new air filter if necessary see Air filter system Starting Stopping the Engine Positions of the Master Control lever z x o lt ao S Ss Stop 0 engine off ignition is switched off Run I engine is running or can start Warm start this position is for starting the warm engine the master control lever returns to run when the throttle trigger is squeezed Cold start this position is for starting the cold engine MS 231 MS 231 C MS 251 MS 251 C Adjusting the Master Control lever To adjust the Master Control lever from run I to cold start press and hold down the throttle trigger lockout and throttle trigger simultaneously set master control lever To set the master control lever to warm start first set it to cold start M4 then push the master control lever into the warm start position Switching to the warm start position is only possible from the cold start position Simultaneously pressing the throttle trigger lockout and blipping
27. audibly chain brake is released Fitting the saw chain z x a 5 lt ao amp 2310BA016 KN e Place the saw chain on the chain e Position tensioning gear 1 and sprocket 2 guide bar 3 relative to one another e Slide the guide bar over the collar screw 3 the head oftherear collar screw must protrude into the oblong hole z N 5 lt a So an N e Insert and tighten screw 2 181BA012 KN warnine Put on protective gloves risk of injury by the sharp cutters 20 MS 231 MS 231 C MS 251 MS 251 C 135BA011 KN Guide the drive link into the bar groove see arrow and turn the tensioning gear to the left as far as possible e Fit chain sprocket cover sliding the guide lugs into the engine housing openings zZ x 2 ch D N When fitting the chain sprocket cover the teeth of the adjusting wheel and the tensioning gear must mesh if necessary MS 231 MS 231 C MS 251 MS 251 C turn the adjusting wheel 4 a little until the chain sprocket cover can be slid completely against the engine housing Swing grip 5 into position until it engages Fit wing nut and tighten lightly Next step see Tensioning the Saw Chain English Tensioning the Saw Chain side chain tensioner Soo ot z x o lt a a Retensioning during cutting work Switch off the engine Loosen the
28. chapter on Operating Instructions Fuel Your engine requires a mixture of gasoline and engine oil Aware For health reasons avoid direct skin contact with gasoline and avoid inhaling gasoline vapor STIHL MotoMix STIHL recommends the use of STIHL MotoMix This ready to use fuel mix contains no benzol or lead has a high octane rating and ensures that you always use the right mix ratio STIHL MotoMix uses STIHL HP Ultra two stroke engine oil for an extra long engine life MotoMix is not available in all markets Mixing Fuel Elon Unsuitable fuels or lubricants or mix ratios other than those specified may result in serious damage to the engine Poor quality gasoline or engine oil may damage the engine sealing rings hoses and the fuel tank Gasoline Use only high quality brand name gasoline with a minimum octane rating of 90 leaded or unleaded MS 231 MS 231 C MS 251 MS 251 C If your machine is equipped with a catalytic converter you must use unleaded gasoline liere A few tankfuls of leaded gasoline will greatly reduce the efficiency of the catalytic converter Gasoline with an ethanol content of more than 10 can cause running problems in engines with a manually adjustable carburetor and should not be used in such engines Engines equipped with M Tronic deliver full power when run on gasoline with an ethanol content of up to 25 E25 Engine oil Use only high quality two stroke
29. e bar in the cut Be very careful With freely hanging limbs With trunks that are under tension between other trees because they fell unfavourably When working in windbreaks In these cases do not use a chain saw use a hoist winch or dragline instead Pull out trunks that are lying about and have been cut free Whenever possible deal with them in open areas MS 231 MS 231 C MS 251 MS 251 C Dead wood brittle rotten or dead wood poses a significant highly unpredictable hazard It is extremely difficult or even practically impossible to recognise the danger Use aids such as winches or draglines When felling close to roads rail lines power lines etc work with particular care If necessary notify police power companies or railway authorities English Working Techniques Sawing and felling work including all related work plunge cutting limbing etc may only be carried out by persons who have been specially trained and instructed Persons who are not experienced chain saw users should not carry out any such work increased risk of accidents Country specific legislation on felling technique must be complied with during felling work Cutting Do not operate your saw with the starting throttle lock engaged Engine speed cannot be controlled with the throttle trigger in this position Work calmly and carefully in daylight conditions and only when visibility is good Ensure yo
30. eck that the clutch drum is in perfect working condition Always store fuel and chain lubricant only in the specified type of containers and ensure they are correctly labelled Store in a dry cool and secure place protected against light and sunlight In the event of a chain brake malfunction switch off the machine immediately risk of injury Consult a English Reactive Forces The most common reactive forces are kickback pushback and pull in Dangers of kickback Kickback can result in fatal cuts zZ ise gt lt a S Kickback occurs when the saw is suddenly thrown up and back in an uncontrolled arc towards the operator Kickback occurs if for example z x 10 N lt a o The saw chain in the area of the upper quarter of the guide bar nose unintentionally comes into contact with wood or a solid object e g unintentionally touches another limb during limbing The saw chain at the nose of the guide bar is briefly pinched in the cut QuickStop chain brake This device reduces the risk of injury in certain situations it cannot prevent kickback If activated the brake stops the saw chain within a fraction of a second refer to chapter Chain brake in this Instruction Manual Reducing the risk of kickback Work cautiously and methodically Hold the chain saw firmly with both hands and maintain a secure grip Always cut at full throt
31. er Oil filler cap Muffler Front hand guard Front handle handlebar Spark plug boot Starter grip Fuel filler cap Master Control lever Throttle trigger Throttle trigger lockout Rear handle Rear hand guard Serial number 1 2310BA029 ST 1 Depending on model 46 MS 231 MS 231 C MS 251 MS 251 C Specifications Engine STIHL single cylinder two stroke engine MS 231 MS 231 C Displacement 42 6 cm Bore 42 5mm Stroke 30 mm Engine power to 2 0 kW 2 7 HP ISO 7293 at 10 000 rpm Idle speed 2 800 rpm MS 251 MS 251 C Displacement 45 6 cm Bore 44mm Stroke 30 mm Engine power to 2 2 kW 3 0 bhp ISO 7293 at 10 000 rpm Idle speed 2 800 rpm 1 to ISO 11681 50 rpm Ignition System Electronic magneto ignition Spark plug resistor NGK CMR6H type BOSCH USR 4AC Electrode gap 0 5 mm Fuel System All position diaphragm carburetor with integral fuel pump MS 231 MS 231 C MS 251 MS 251 C Fuel tank capacity 390 cc 0 39 Chain Lubrication Fully automatic speed controlled oil pump with rotary piston Oil tank capacity 200 cc 0 2 Weight dry without bar and chain MS 231 4 9 kg MS 231 C with ErgoStart and quick chain tensioner 5 2 kg MS 251 4 9kg MS 251 C with ErgoStart and quick chain tensioner 5 2 kg Cutting Attachment Actual cutting length may be less than the specified length 325 Rollomatic E
32. ergency switch off the engine immediately by moving the Master Control lever stop switch to STOP 0 or U English Never let the machine run unattended Exercise caution with slippery surfaces water snow ice steep slopes uneven ground or green wood that has just been stripped of its bark danger of slipping Use caution with tree stumps roots ditches danger of stumbling Do not work alone keep within calling distance of others who are trained in emergency procedures and can provide help in an emergency Helpers at the cutting site must also wear protective clothing helmet and stand well clear of the branches being cut More care and attention than usual are required when wearing ear protection as warning sounds shouts beeps etc cannot be heard properly Take a break in good time to avoid tiredness or exhaustion risk of accidents Dust e g sawdust fumes and smoke produced while using the machine may be hazardous to health If dust is generated wear a dust mask When the engine is running Note that the saw chain continues to rotate for a short period after you let go of the throttle trigger coasting effect No smoking when working with or near the chain saw risk of fire Combustible fuel vapour may escape from the fuel system English Examine the saw chain periodically at short intervals and as soon as you note any tangible changes Switch off the engine wait un
33. gger 3 the master control lever 4 jumps to run I and the engine begins to idle Elisi The engine must be switched to idle immediately otherwise damage to the engine housing and chain brake may occur when the chain brake is locked 31 English z x x m 2 3 e Pull the hand guard toward the handlebar The chain brake is released the chain saw is ready for use lhon Open the throttle only when the chain brake is off Increased engine speeds with the chain brake on saw chain is stationary will quickly damage the clutch and chain brake At very low temperatures e Let the engine warm up briefly with the throttle slightly open if necessary configure for winter operation see Winter Operation Switch off the engine Move the master control lever to the stop position 0 If the engine does not start The master control lever was not returned from the position cold start J to warm start in time the engine may be flooded 32 Move the master control lever to the stop position 0 Remove the spark plug see Spark plug Dry the spark plug Crank the engine several times with the starter to clear the combustion chamber Replace the spark plug see Spark plug Set the master control lever to warm start even if the engine is cold Restart the engine Operating Instructions During the break in period A factory new machine should not be run at high re
34. haft and bearings After a long period of full throttle operation After a long period of full throttle operation allow engine to run for a while at idle speed so that the heat in the engine can be dissipated by flow of cooling air This protects engine mounted components ignition carburetor from thermal overload After finishing work Slacken off the chain if you have retensioned it at operating temperature during work MS 231 MS 231 C MS 251 MS 251 C Elon Always slacken off the chain again after finishing work The chain contracts as it cools down If it is not slackened off it can damage the crankshaft and bearings Short term storage Wait for engine to cool down Keep the machine with a full tank of fuel in a dry place well away from sources of ignition until you need it again Long term storage See Storing the machine English Taking Care of the Guide Bar 143BA026 KN e Flip the bar after each sharpening and each time the chain is changed to avoid uneven wear especially at the sprocket nose and on the bottom Periodically clean the oil inlet hole 1 oil outlet channel 2 and bar groove 3 Measure groove depth using the measuring tool on the file gauge special accessory in the area with the greatest wear 33 English Chain type Chain pitch Minimum groove depth Picco 1 4 P 4 0 mm Rapid 1 4 4 0 mm Picco 3 8 P 5 0 mm Rapid 3 8 0 325
35. hand Refit the rim sprocket cavities toward the outside Refit washer and E clip on the crankshaft MS 231 MS 231 C MS 251 MS 251 C Maintaining and Sharpening the Saw Chain Sawing effortlessly with a properly sharpened saw chain A properly sharpened saw chain cuts through wood effortlessly even with very little pushing Never use a dull or damaged saw chain this leads to increased physical strain increased vibration load unsatisfactory cutting results and increased wear e Clean the saw chain Check the saw chain for cracks and damaged rivets Replace damaged or worn chain components and adapt these parts to the remaining parts in terms of shape and level of wear rework accordingly Carbide tipped Duro saw chains are especially wear resistant For an optimal sharpening result STIHL recommends STIHL servicing dealers warnine Compliance with the angles and dimensions listed below is absolutely necessary An improperly sharpened saw chain especially depth gauges that are too low can lead to increased kickback tendency of the chain saw risk of injury English Chain pitch z x N a o lt ay a The chain pitch marking a is embossed in the area of the depth gauge of each cutter Marking a Chain pitch Inches mm 7 114P 6 35 1 or 1 4 1 4 6 35 6 P or PM 3 8P 9 32 2 or 325 0 325 8 25 3 or 3 8 3 8 9 32 4 or 404 0 404 10 26 The diameter of fi
36. hen at the tension side 2 the saw may otherwise pinch or kick back risk of injury MS 231 MS 231 C MS 251 MS 251 C 001BA151 KN zZ x a ire lt a 8 ro Make relieving cut at the compression side 1 Make bucking cut at the tension side 2 Be wary of pushback when making bucking cut from the bottom upwards underbuck Blvorice Do not cut a lying log at a point where it is touching the ground because the saw chain will otherwise be damaged MS 231 MS 231 C MS 251 MS 251 C Ripping cut z x D x ao Q Cutting technique in which the spiked bumper is not used risk of pull in start the cut with the guide bar at the shallowest possible angle take extra care since there is an increased danger of kickback Preparations for Felling Check that there are no other persons in the felling area other than helpers Make sure no one is endangered by the falling tree the noise of your engine may drown any warning calls English rf a gt lt a Maintain a distance of at least 2 1 2 tree lengths from the next felling site Determine direction of fall and escape path Select gap in stand into which you want the tree to fall Pay special attention to the following points The natural lean of the tree Any unusually heavy limb structure damage The wind direction and speed do not fell in high winds
37. improvements STIHL s philosophy is to continually improve all of its products For this reason we may modify the design engineering and appearance of our products periodically Therefore some changes modifications and improvements may not be covered in this manual MS 231 MS 231 C MS 251 MS 251 C Safety Precautions Special safety precau tions must be observed to reduce the risk of per sonal injury when working with a chain saw because of the very high chain speed and very sharp cutters It is important that you read the instruction man ual before first use and keep it in a safe place for future reference Non observance of the instruction manual may result in serious or even fatal injury General Observe all applicable local safety regulations standards and ordinances The use of noise emitting power tools may be restricted to certain times by national or local regulations If you have not used this model before Have your dealer or other experienced user show you how to operate your machine or attend a special course in its operation Minors should never be allowed to use a chain saw Keep bystanders especially children and animals away from the work area The user is responsible for avoiding injury to third parties or damage to their property MS 231 MS 231 C MS 251 MS 251 C Do not lend or rent your chain saw without the instruction manual Be sure that anyone using it understa
38. ing that could get caught on branches or brush or moving parts of the saw Do not wear a scarf necktie or jewelry Tie up and confine long hair e g with a hair net cap hard hat etc K Wear steel toed safety boots with cut retardant inserts and non slip soles Awornine aa To reduce the risk of eye injuries wear snug fitting aces LY safety glasses in accord ance with European Standard EN 166 Make sure the safety glasses are a good fit Wear a face shield and make sure it is a good fit A face shield alone does not provide adequate eye protection Wear hearing protection e g earplugs or ear muffs Wear a safety hard hat where there is a danger of head injuries from falling objects English Wear heavy duty work gloves made of durable material e g leather STIHL offers a comprehensive range of personal protective clothing and equipment Transport Before any transport even over short distances switch off the machine engage the chain brake and attach the chain scabbard This avoids the risk of the saw chain starting unintentionally z wo a Always carry the chain saw by the handle with the hot muffler away from your body the guide bar must point to the rear Avoid touching hot parts ofthe machine especially the surface of the muffler risk of burns In vehicles Properly secure the machine to prevent tipping damage and chain oil or fuel spillage
39. isted in relation to top Remove the cap from the fuel tank and check it from above MS 231 MS 231 C MS 251 MS 251 C 001BA238 KN Left Bottom of cap is twisted inner mark 1 in line with outer mark Right Bottom of cap in correct posi tion inner mark is under the grip It is not in line with the outer mark z x D o a lt ao 5 Ss e Place the cap on the opening and rotate it counterclockwise until it engages the filler neck e Continue rotating the cap counterclockwise about a quarter turn this causes the bottom ofthe cap to be turned to the correct position e Turnthe cap clockwise and lock it in position see section on Closing English Chain Lubricant For automatic and reliable lubrication of the chain and guide bar use only an environmentally compatible quality chain and bar lubricant Rapidly biodegradable STIHL BioPlus is recommended Elone Biological chain oil must be resistant to aging e g STIHL BioPlus since it will otherwise quickly turn to resin This results in hard deposits that are difficult to remove especially in the area of the chain drive and chain It may even cause the oil pump to seize The service life of the chain and guide bar depends on the quality of the lubricant It is therefore essential to use only a specially formulated chain lubricant warnine Do not use waste oil Renewed contact with waste oil can cause skin ca
40. it each time e during starting press down on the handlebar do not pull out the starter rope all the way risk of breakage e Donotlet the starter grip snap back guide it vertically back into the housing so that the starter rope can rewind properly MS 231 MS 231 C MS 251 MS 251 C Starting the chain saw A warnine There must not be anyone within the swivel range of the chain saw Observe safety precautions Versions with fuel pump e Press the fuel pump bulb at least five times even if it is still full of fuel e For all versions z x a t e lt a o N N Push the hand guard 1 forwards the saw chain is blocked Simultaneously press the throttle trigger lockout 2 and throttle trigger 3 set master control lever 4 Position cold start M4 If engine is cold even if the engine has stalled during opening of throttle after starting Position warm start MS 231 MS 231 C MS 251 MS 251 C If engine is warm once the engine has been running for approx one minute Hold and start the chain saw English When the engine has turned over for the first time I a ru 7199199191715 177 2310BA003 KN Move the Master Control lever 4 to the position warm start Hold and start the chain saw Once the engine is running J I5 5 EE TI EI ce HE TE 1 2310BA004 KN e Press the throttle trigger lockout and blip the throttle tri
41. k chain lubrication and the oil level in the tank before starting work Every new chain has to be broken in for about 2 to 3 minutes After breaking in the chain check chain tension and adjust if necessary see Checking Chain Tension MS 231 MS 231 C MS 251 MS 251 C Chain Brake SNe Locking the chain 143BA011 KN in an emergency when starting atidling speed The chain brake is activated by pushing the hand guard toward the bar nose with your left hand or by inertia in certain kickback situations The chain is stopped and locked MS 231 MS 231 C MS 251 MS 251 C Releasing the chain brake zZ x a lt oO ise e Pull the hand guard back toward the front handle B orice Always disengage chain brake before accelerating the engine except when checking its operation and before starting cutting work High revs with the chain brake engaged chain locked will quickly damage the powerhead and chain drive clutch chain brake The chain brake is also activated by the inertia of the front hand guard if the kickback force of the saw is high enough The hand guard is accelerated toward the bar nose even if your left hand is not behind the hand guard e g during felling cut English The chain brake will operate only if the hand guard has not been modified in any way Check operation of the chain brake Before starting work Run engine at idle
42. k the idle setting regularly and correct when possible Have the machine repaired by a STIHL servicing dealer if the saw chain still continues to move during idling The chain saw produces poisonous exhaust gases as soon as the engine starts These gases may be colourless and odour less and may contain unburnt hydrocarbons and benzene Never work with the machine indoors or in poorly ventilated areas even if your machine is equipped with a catalytic converter Ensure proper ventilation when working in trenches hollows or other confined locations risk of fatal injury from breathing toxic fumes If you feel sick have a headache vision problems e g your field of vision gets smaller hearing problems dizziness or inability to concentrate stop work immediately Such symptoms may be caused by an excessively high concentration of exhaust emissions risk of accident After finishing work Switch off the motor engage the chain brake and attach the chain scabbard Storage When the machine is not in use it should be stored in such a way that no one is endangered Secure the machine against unauthorised use Store the machine in a safe dry room Vibrations Prolonged use of the power tool may result in vibration induced circulation problems in the hands whitefinger disease No general recommendation can be given for the length of usage because it depends on several factors The period of usage is
43. larly given the opportunity to attend training courses and are supplied with the necessary technical information If these maintenance operations are not carried out as specified the user assumes responsibility for any damage that may occur Among other parts this includes Damage to the engine due to neglect or deficient maintenance e g air and fuel filters incorrect carburetor adjustment or inadequate cleaning of cooling air inlets intake ports cylinder fins Corrosion and other consequential damage resulting from improper storage Damage to the machine resulting from the use of poor quality replacement parts Parts Subject to Wear and Tear Some parts of the power tool are subject to normal wear and tear even during regular operation in accordance with instructions and depending on the type and duration of use have to be replaced in good time Among other parts this includes Saw chain guide bar Drive components clutch clutch drum chain sprocket Filters air oil fuel Starter mechanism Spark plug Components of antivibration system 45 English Main Parts Shroud lock Carburetor adjusting screws Fuel pump Shutter summer and winter operation Chain brake Chain sprocket Chain sprocket cover Chain catcher Side chain tensioner Spiked bumper Guide bar Oilomatic chain Adjusting wheel quick chain adjuster Handle of wingnut quick chain adjust
44. le to be used depends on the chain pitch see table Sharpening tools The angles of the cutter must be maintained during resharpening 39 English Sharpening and side plate angles zZ x A is lt ao a A Sharpening angle STIHL saw chains are sharpened with a 30 sharpening angle Ripping chains which are sharpened with a 10 sharpening angle are exceptions Ripping chains have an X in the designation B Side plate angle The correct side plate angle results automatically when the specified file holder and file diameter are used Tooth shapes Angle A B Micro semi chisel tooth 30 75 e g 63 PM3 26 RM3 36 RM Super full chisel tooth 30 60 e g 63 PS3 26 RS 36 RS3 Ripping chain e g 10 75 63 PMX 36 RMX The angles must be identical for all cutters in the saw chain Varying angles Rough uneven running of the saw chain increased wear even to the point of saw chain breakage 40 File holder 689BA025 KN e Use a file holder Always use a file holder special accessory see table Sharpening tools when sharpening saw chains by hand File holders have markings for the sharpening angle Use only special saw chain files Other files are unsuitable in terms of shape and type of cutting To check the angles 85 75 U 80 day RN Ee 001BA203 KN STIHL filing gauge special accessory see table Sharpening tools
45. lockwise as far as possible max 3 4 turn Turn the low speed adjusting screw L clockwise until it is firmly in its seat then back off 1 4 turn Setting the idle speed Make standard setting e Start engine and let it warm up 35 English z x A S lt ao a v N Engine stops when idling e Turn the idle speed adjusting screw LA clockwise until the saw chain begins to run then turn it back 2 3 4 turn Saw chain rotates at idle speed e Turn the idle speed screw LA counterclockwise until the saw chain stops turning then turn another 2 3 4 turns in the same direction warnine If the saw chain continues to keep rotating in idle even after adjustment have the chain saw checked by a servicing dealer Speed erratic when idling poor acceleration despite standard setting of low speed adjusting screw The idle setting is too lean e Carefully turn the low speed adjusting screw L counterclockwise until the engine runs smoothly and accelerates properly 36 Whenever the low speed adjusting screw L has been adjusted it is usually also necessary to readjust the idle speed adjusting screw LA Correcting the carburetor setting for use at high altitudes The setting may have to be marginally corrected if engine performance is unsatisfactory at high altitudes e Make standard setting Let the engine warm up e Turn the high speed adjusting screw H slightly clock
46. nated clothing must be changed immediately The machines can be equipped with the following filler caps as standard Cliplock filler cap bayonet type Place the cliplock filler cap bayonet type in position turn as far as stop and fold the cliplock oe down This helps reduce the risk of unit vibrations causing an incorrectly tightened filler cap to loosen or come off and spill quantities of fuel Look out for leaks Never start the engine if fuel has been spilled or is leaking Fatal burns may result Before Starting Work Check that your saw is properly assembled and in good condition refer to appropriate chapters in the instruction manual Check the fuel system for leaks paying special attention to visible parts such as the tank cap hose connections and the manual fuel pump on machines so equipped If MS 231 MS 231 C MS 251 MS 251 C there are any leaks or damage do not start the engine risk of fire Have your saw repaired by a servicing dealer before using it again Check operation of chain brake front hand guard Correctly mounted guide bar Correctly tensioned chain The trigger and trigger lockout must move freely and spring back to the idle position when they are released Master Control lever must move easily to STOP O or Check that the spark plug boot is secure a loose boot may cause arcing that could ignite combustible fumes and cause a fire
47. ncer Moreover waste oil is environmentally harmful Ehon Waste oil does not have the necessary lubricating properties and is unsuitable for chain lubrication 25 English Filling Chain Oil Tank Preparations zZ x 1 lt ao Ss Thoroughly clean the oil filler cap and the area around it to ensure that no dirt falls into the tank e Position the machine so that the filler cap is facing up Open the filler cap Fill up with chain oil Refill the chain oil tank every time you refuel Take care not to spill chain oil while refilling and do not overfill the tank STIHL recommends you use the STIHL filler nozzle for chain oil special accessory e Close the filler cap There must still be a small amount of oil in the oil tank when the fuel tank is empty 26 If the oil level in the tank does not go down the reason may be a fault in the oil supply system Check chain lubrication clean the oilways contact your dealer for assistance if necessary STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL servicing dealer Checking Chain Lubrication z x x a is lt ao 7 The saw chain must always throw off a small amount of oil B vorice Never operate your saw without chain lubrication If the chain runs dry the whole cutting attachment will be irretrievably damaged within a very short time Always chec
48. nds the information contained in this manual To operate a chain saw you must be rested in good physical condition and mental health If you have any condition that might be aggravated by strenuous work check with your doctor before operating a chain saw Do not operate the chain saw if you are under the influence of any substance drugs alcohol which might impair vision dexterity or judgment To reduce the risk of accidents or injury put off the work in poor weather conditions rain snow ice wind Persons with pacemakers only The ignition system of your chainsaw produces an electromagnetic field of a very low intensity This field may interfere with some pacemakers To reduce health risks STIHL recommends that persons with pacemakers consult their physician and the pacemaker manufacturer before operating this power tool Intended use The machine may only be used to saw wood and wooden objects Do not the machine for any other purpose risk of accidents Do not modify the machine in any way this may increase the risk of personal injury STIHL excludes all liability for personal injury and damage to property caused while using unauthorised attachments English Clothing and Equipment Wear proper protective clothing and equipment Clothing must be sturdy but allow complete free dom of movement Wear snug fitting clothing with cut retardant inserts do not wear a work coat Avoid cloth
49. odern production techniques and comprehensive quality assurance Every effort has been made to ensure your satisfaction and troublefree use of the product Please contact your dealer or our sales company if you have any queries concerning this product Your a Dr Nikolas Stihl This instruction manual is protected by copyright All rights reserved especially the rights to reproduce translate and process with electronic systems English Guide to Using this Manual This Instruction Manual refers to a STIHL chain saw also called amachine in this Instruction Manual Pictograms Pictograms that appear on the machine are explained in this Instruction Manual Depending on the machine and equipment version the following pictograms may appear on the machine Fuel tank fuel mixture of gasoline and engine oil mi Tank for chain oil chain oil Engage and release chain brake O Coasting brake Direction of chain travel Ematic chain oil flow adjustment 7E e Ye Tension saw chain Intake air baffle winter operation Intake air baffle summer operation Handle heating Actuate decompression valve oo dd U JI Actuate manual fuel pump Symbols in text warnine Warning where there is a risk of an accident or personal injury or serious damage to property Elore Caution where there is a risk of damaging the machine or its individual components Engineering
50. out 1 5 to 1 3 of the trunk diameter MS 231 MS 231 C MS 251 MS 251 C Determine direction of fall with gunning sight on shroud and fan housing x oy 02 lt ao S 3 Your chainsaw has a gunning sight on the shroud and fan housing Use this gunning sight Making Felling Notch Position the saw so that the felling notch is ata right angle to the direction you want the tree to fall The sequence in which the felling notch is made with a horizontal cut bottom and angled cut top is defined in country specific regulations Make horizontal cut bottom Make the angled cut top at about 45 60 to the horizontal cut MS 231 MS 231 C MS 251 MS 251 C Check direction of fall 001BA153 KN e Position the saw in the horizontal cut The gunning sight must point in the planned direction of fall if necessary correct direction of fall by re cutting the felling notch Sapwood cuts z amp o B a S S Sapwood cuts in long fibered softwood help prevent sapwood splintering when the tree falls Make cuts at both sides of the trunk at same height as bottom of English felling notch to a depth of about 1 10 of trunk diameter On large diameter trees cut to no more than width of guide bar Do not make sapwood cuts if wood is diseased Basic Information on Felling Cut Stump dimensions z x o red N lt ao gt The felling notch C determines
51. prolonged by Hand protection wearing warm gloves Work breaks The period of usage is shortened by Any personal tendency to suffer from poor circulation symptoms frequently cold fingers tingling sensations Low outside temperatures The force with which the handles are held a tight grip restricts circulation Continual and regular users should monitor closely the condition of their hands and fingers If any of the above symptoms appear e g tingling sensation in fingers seek medical advice MS 231 MS 231 C MS 251 MS 251 C Maintenance and repairs Always switch off the engine before any repair cleaning or maintenance work and any work on the chain Risk of injury if the engine starts inadvertently Exception adjustment of carburettor and idle speed The machine must be serviced regularly Do not attempt any maintenance or repair work not described in the Instruction Manual All other work should be carried out by a servicing dealer STIHL recommends that maintenance and repair work be carried out only by authorised STIHL dealers STIHL dealers receive regular training and are supplied with technical information Use only high quality spare parts Otherwise there may be a risk of accidents and damage to the machine If you have any questions in this respect consult a servicing dealer Do not modify the machine in any way this may increase the risk of personal injury risk of
52. rsons Checking and Replacing the Chain Sprocket Remove chain sprocket cover saw chain and guide bar Release chain brake pull hand guard against the front handle Fit new chain sprocket after use of two saw chains or earlier if the wear marks arrows are deeper than 0 5 mm otherwise the service life ofthe saw chain is reduced use check gauge special accessory to test Using two saw chains in alternation helps preserve the chain sprocket STIHL recommends use of original STIHL chain sprockets in order to ensure optimal functioning of the chain brake z N A a z S Use a screwdriver to remove the E clip 1 Remove the washer 2 Remove rim sprocket 3 Inspect transport profile on the clutch drum 4 if there are also heavy signs of wear also replace the clutch drum Remove clutch drum or spur chain sprocket 5 including needle cage 6 from the crankshaft with QuickStop Super chain brake press throttle trigger lockout beforehand Install spur chain sprocket rim sprocket Clean crankshaft stub and needle cage and lubricate with STIHL lubricant special accessory Slide needle cage onto the crankshaft stub MS 231 MS 231 C MS 251 MS 251 C e After refitting turn the clutch drum and or spur chain sprocket approx 1 full turn so that the carrier for the oil pump drive engages with QuickStop Super chain brake press throttle trigger lockout before
53. the direction of fall The hinge D helps control the falling tree Width of hinge about 1 10 of tree diameter To reduce the risk of accidents do not cut through the hinge you could lose control of the direction of fall Leave a broader hinge on rotten trees 13 English The tree is felled with the felling cut E Cut horizontally 1 10 at least 3 cm of width of hinge D higher than bottom of felling notch C The holding strap F or stabilizing strap G supports the tree and helps prevent it from falling prematurely Width of strap about 1 10 to 1 5 of tree diameter Do not cut into the strap while making the felling cut Leave a broader strap on rotten trees Plunge cutting For relieving cuts during bucking For wood carving A I 1 1 i I 1 1 t 1 k v 4 2 N SI A 1 U o Q N 001BA269 KN e Use a low kickback chain and exercise particular caution 14 1 Begin cut by applying the lower portion of the guide bar nose do not use upper portion because of risk of kickback Start cutting at full throttle until depth of kerf is twice the width of the guide bar 2 Swing saw slowly into plunge cutting position take care because of the risk of kickback or pushback 3 Make the plunge cut very carefully Danger of pushback zZ x o S 2 ao Q Use the plunge cutting sight if possible
54. the left hand thumb wrapped around the handlebar 30 Starting Standard versions z x 2 o lt a el N e With the right hand pull the starter grip slowly until you feel it engage and then give it a brisk strong pull simultaneously press down on the handlebar do not pull the starter rope out all the way risk of breakage Do not let the starter grip snap back guide it vertically back into the housing so that the starter rope can rewind properly With a new engine or after a long period of disuse with machines without an additional manual fuel pump it may be necessary to pull the starter rope several times to prime the fuel line Versions with ErgoStart warning This machine is extremely simple and easy to start even for children risk of accident Make absolutely certain that children or other unauthorized persons cannot attempt to start the machine never leave the machine unattended during work breaks secure storage after work The ErgoStart stores the energy for starting the chain saw Forthis reason a few seconds may pass between the pulling of the starter rope and the starting of the engine For versions with ErgoStart there are two ways to start the machine e with the right hand pull the starter grip slowly and smoothly or with the right hand pull the starter grip in several short pulls of the starter rope pulling the rope out only a little b
55. the throttle trigger causes the master control lever to jump from the warm start position to run I To switch off the engine set the master control lever to Stop 0 Position cold start M Ifthe engine is cold Ifthe engine stalls during opening of throttle after starting Ifthe fuel tank has run empty engine stalled out Position warm start If engine is warm once the engine has been running for approx one minute When the engine has fired for the first time After ventilation of the combustion chamber if the engine was flooded MS 231 MS 231 C MS 251 MS 251 C Fuel pump Press the fuel pump bulb several times even if it is still full of fuel When starting for the first time Ifthe fuel tank has run empty engine stalled out Holding the chain saw There are two ways to hold the chain saw during starting English On the ground Zz x 2 ao D N e Place the chain saw securely on the ground assume a steady stance the saw chain must not touch any objects and also must not touch the ground e With the left hand on handlebar press the chain saw firmly against the ground thumb wrapped around the handlebar Place your right foot into the rear handle 29 English Between the knees or thighs z x Q 2 S lt ao el N e Clamp the rear handle between the knees or thighs e Grip the handlebar firmly with
56. til the saw chain is stationary Check condition and secure fitting Check sharpness Never touch the saw chain when the engine is running If the saw chain becomes jammed by an object switch off the engine immediately before attempting to remove the object risk of injury Always turn off the engine before leaving the machine unattended To change the saw chain switch off the engine Risk of injury from the motor starting unintentionally Keep easily combustible materials e g wood chips bark dry grass fuel away from hot exhaust gases and hot mufflers risk of fire Mufflers with catalytic converters can become especially hot Never work without chain lubrication monitor the oil level in the oil tank Stop work immediately if the oil level in the oil tank is too low and top up with chain oil see also Topping up with chain oil and Check chain lubrication If the machine is subjected to unusually high loads for which it was not designed e g heavy impact or a fall always check that it is in good condition before continuing work see also Before starting work Check the fuel system for leaks and make sure the safety devices are working properly Never continue using a machine that is not in perfect working order In case of doubt have the unit checked by your servicing dealer Check for correct idling so that the saw chain stops moving when the throttle trigger is released Chec
57. tle Beaware of the location of the guide bar nose Do not cut with the guide bar nose Be especially careful with small tough limbs undergrowth and offshoots the saw chain may become caught in them Never cut several limbs at once Do not lean too far forward Do not cut above shoulder height Use extreme caution when re entering a previous cut Do not attempt plunge cuts if you are not experienced in this cutting technique Be alert for shifting of the log or other forces that may cause the cut to close and pinch the chain Always cut with a correctly sharpened properly tensioned saw chain the depth gauge setting must not be too large Use low kickback saw chains as well as narrow radius guide bars Pull in A 001BA037 KN When the chain on the bottom of the bar overbucking is suddenly pinched caught or encounters a foreign object in the wood the chain saw may suddenly MS 231 MS 231 C MS 251 MS 251 C be drawn forward toward the log to avoid this engage the bumper spike firmly in the wood Pushback B zZ g 8 S lt a gt S When the chain on the top of the bar underbucking is suddenly pinched caught or encounters a foreign object in the wood the chain saw may suddenly be driven straight back toward the operator to avoid this Do not allow the top of the guide bar to become jammed Do not twist the guid
58. turn counterclockwise and remove in the direction of the rear handle e Always replace a damaged filter Cleaning the air filter e Knock out the filter or blow it clear with compressed air from the inside outwards If knocking out or blowing out does not suffice or in the case of stubborn dirt or stuck filter fabric the filter must be subjected to a thorough cleaning MS 231 MS 231 C MS 251 MS 251 C Thorough filter cleaning e Wash the filter in STIHL special purpose cleaner special accessory or a clean non flammable cleaning liquid e g warm soapy water rinse the filter from inside to out under a water jet do not use high pressure cleaners e Dry all filter parts do not expose to extreme heat e Do not oil the filter e Reinstall filter Installing the air filter e Fit air filter e Press the air filter in the direction of the filter housing and simultaneously turn it clockwise until the air filter engages the STIHL logo must be horizontal e Fit the shroud see Shroud English Adjusting the Carburetor Basic information The carburetor comes from the factory with a standard setting The carburetor has been adjusted for optimum performance and fuel efficiency in all operating states Standard setting Switch off the engine Check the air filter clean or replace it if necessary zZ x N A S z d S D N e Turn the high speed adjusting screw H counterc
59. u do not endanger others stay alert at all times First time users are advised to practice cutting logs on a sawhorse see When cutting small logs Use the shortest possible guide bar The chain guide bar and chain sprocket must match each other and your saw English Zz d a S lt a S Ss Position the saw so that your body is clear of the cutting attachment Always pull the saw out of the cut with the chain running Use your chain saw for cutting only It is not designed for prying or shoveling away limbs roots or other objects Do not underbuck freely hanging limbs Take care when cutting scrub and young trees The saw chain may catch and throw thin shoots in your direction To reduce the risk of injury take special care when cutting shattered wood because of the risk of injury from slivers being caught and thrown in your direction Make sure your saw does not touch any foreign materials Stones nails etc may be flung off and damage the saw chain The saw may kick back unexpectedly risk of accidents If the rotating chain makes contact with a rock or other solid object there is a risk of sparking which may cause easily combustible material to catch fire under certain circumstances Dry plants and scrub are also easily combustible especially in hot and dry weather conditions If there is a risk of fire do not use your chainsaw near combustible 10 materials dry plants or scrub
60. utter to be checked if the depth gauge protrudes past the file gauge the depth gauge must be reworked ia x gt lt ao D pel e Afterwards dress the leading edge of the depth gauge parallel to the service mark see arrow when doing this be careful not to further lower the highest point of the depth gauge 41 English d warning Depth gauges that are too low increase the kickback tendency of the chain saw Pr x a Q e lt ao D e Lay the file gauge on the saw chain the highest point of the depth gauge must be flush with the file After sharpening clean the saw chain thoroughly removing any filings or grinding dust lubricate the saw chain thoroughly In the event of extended periods of disuse store saw chains in cleaned and oiled condition gauge Sharpening tools special accessories Chain pitch Round file Round file File holder File gauge Taper square file Sharpening set Inches mm mm Inches Part number Part number Part number Part number Part number 1 4P 6 35 3 2 1 8 5605 771 3206 56057504300 0000 8934005 0814 252 3356 5605 007 1000 1 4 6 35 4 0 5 32 5605 7724006 56057504327 11108934000 0814 252 3356 5605 007 1027 3 8 P 9 32 4 0 5 32 5605 7724006 56057504327 11108934000 0814 252 3356 5605 007 1027 0 325 8 25 4 8 3 16 5605 7724806 5605 7504328 1110 893 4000 0814 252 3356 5605 007 1028 3 8 9 32 5 2 13 64 56057725206 5605 7504329
61. vicing dealer 2 44 Firmly tighten down the cylinder base screws of professional saws 3 4 kW or more after 10 to 20 hours of operation MS 231 MS 231 C MS 251 MS 251 C Minimize Wear and Avoid Damage Observing the instructions in this manual helps reduce the risk of unnecessary wear and damage to the power tool The power tool must be operated maintained and stored with the due care and attention described in this owner s manual The user is responsible for all damage caused by non observance of the safety precautions operating and maintenance instructions in this manual This includes in particular Alterations or modifications to the product not approved by STIHL Using tools or accessories which are neither approved or suitable for the product or are of a poor quality Using the product for purposes for which it was not designed Using the product for sports or competitive events Consequential damage caused by continuing to use the product with defective components Maintenance Work All the operations described in the Maintenance Chart must be performed on a regular basis If these maintenance operations cannot be performed by the owner they should be performed by a servicing dealer STIHL recommends that you have servicing and repair work carried out exclusively by an authorized STIHL MS 231 MS 231 C MS 251 MS 251 C English servicing dealer STIHL dealers are regu
62. vironmental requirements 23 English Fueling mi Preparing the machine m gen nun EA i lea toss i i iam i E m 001BA229 KN e Before fueling clean the cap and the area around it to ensure that no dirt falls into the fuel tank e Always position the machine so that the cap is facing upwards Opening 001BA236 KN e Raise the grip until it is upright 24 001BA232 KN Turn the cap counterclockwise about a quarter turn 001BA234 KN Marks on tank cap and fuel tank must line up 2 x oO N lt a Remove the cap Filling up with fuel Take care not to spill fuel while fueling and do not overfill the tank STIHL recommends you use the STIHL filler nozzle for fuel special accessory Fill up with fuel Closing 001BA234 KN Grip must be vertical Fit the cap marks on tank cap and fuel tank must line up Press the cap down as far as stop 001BA233 KN a While holding the cap depressed turn it clockwise until it engages in position rA D N lt a gt Ss The marks on the tank cap and fuel tank are then in alignment MS 231 MS 231 C MS 251 MS 251 C 001BA235 KN e Fold the grip down so that it is flush with the top of the cap z J a So Tank cap is locked If the tank cap cannot be locked in the fuel tank opening Bottom of cap is tw
63. vs full throttle off load for the first three tank fillings This avoids unnecessarily 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 shortblock are greater during this period The engine develops its maximum power after about 5 to 15 tank fillings During work Elone Do not make the mixture leaner to achieve an apparent increase in power this could damage the engine see Adjusting the Carburetor Elone Open the throttle only when the chain brake is off Running the engine at high revs with the chain brake engaged chain locked will quickly damage the shortblock and chain drive clutch chain brake Check chain tension frequently A new saw chain must be retensioned more frequently than one that has been in use already for an extended period MS 231 MS 231 C MS 251 MS 251 C Chain cold Tension is correct when the chain fits snugly against the underside of the bar but can still be pulled along the bar by hand Retension if necessary see Tensioning the Saw Chain Chain at operating temperature The chain stretches and begins to sag The drive links must not come out ofthe bar groove on the underside of the bar the chain may otherwise jump off the bar Retension the chain see Tensioning the Saw Chain Blvotice The chain contracts as it cools down If it is not slackened off it can damage the cranks
64. wise leaner max up to the stop lonc After descending from a high altitude restore the carburetor setting to the standard setting If you make the setting too lean it will increase the risk of engine damage through lack of lubrication and overheating Spark Plug Ifthe engine is down on power difficult to start or runs poorly at idle speed first check the spark plug e Fita new spark plug after about 100 operating hours or sooner if the electrodes are badly eroded Install only suppressed spark plugs of the type approved by STIHL see Specifications Removing the spark plug Remove the shroud see Shroud zZ x o a lt a D N e Pull off the spark plug boot Unscrew spark plug MS 231 MS 231 C MS 251 MS 251 C Checking the spark plug 000BA039 KN Clean dirty spark plug Check electrode gap A and readjust if necessary see Specifications e Rectify the problems which have caused fouling of the spark plug Possible causes are Too much oil in fuel mix Dirty air filter Unfavorable running conditions Z x ito e gt lt ao i A warnine If the spark plug comes with a detachable adapter nut 1 screw the adapter onto the thread and tighten it down firmly to reduce the risk of arcing and fire MS 231 MS 231 C MS 251 MS 251 C Installing the spark plug e Fit spark plug by hand

STIHL MS 231, 251

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