MS 231, 251 2 - 43 Instruction Manual
English 7 8 9 28 29 30 31 32 33 34 35 36 Your Dr. Nikolas Stihl 1 Guide to Using this Manual This Instruction Manual refers to a STIHL chain saw, also called a machine in this Instruction Manual. 1.1 Pictograms Pictograms that appear on the machine are explained in this Instruction Manual. Depending on the machine and equipment ver‐ sion, the following pictograms may appear on the machine.
2 Safety Precautions 1.2 Symbols in text WARNING Warning where there is a risk of an accident or personal injury or serious damage to property. NOTICE Caution where there is a risk of damaging the machine or its individual components. 1.3 Engineering improvements STIHL's philosophy is to continually improve all of its products. For this reason we may modify the design, engineering and appearance of our products periodically.
English 2 Safety Precautions 2.6 WARNING To reduce the risk of eye injuries, wear tight-fitting safety goggles con‐ forming to standard EN 166 or a face shield. Make sure that the safety gog‐ gles and the face shield fit correctly. Wear "personal" hearing protection – for exam‐ ple, ear defenders. Wear a hard hat wherever there is any risk of falling objects. Wear sturdy protective gloves made of a resistant material (e.g. leather).
– – – – – – – – – cap, hose connections and the manual fuel pump (on machines so equipped). If there are any leaks or damage, do not start the engine – risk of fire. Have your saw repaired by a serv‐ icing 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.
English Examine the saw chain periodically at short inter‐ vals and as soon as you note any tangible changes: – Switch off the engine; wait until the saw chain is stationary – Check condition and secure fitting – Check sharpness Never touch the saw chain when the engine is running.
3 Reactive Forces 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.
English 4 Working Techniques 3.3 Quickstop chain brake: the chain pulls the saw forward – to reduce this risk, always engage the spiked bumper securely in the tree or limb. 3.6 Pushback (B) This device reduces the risk of injury in certain situations – it cannot prevent kickback. When activated, the chain brake stops the saw chain within a fraction of a second – see the section "Saw chain" in this Instruction Manual. 3.
4 Working Techniques English chain saw in the vicinity of easily combustible materials, dry plants or scrub. It is mandatory that you ask the responsible forestry office about the current fire hazard. Country-specific legislation on felling technique must be complied with during felling work. 4.1 Sawing Do not operate your saw with the starting throttle lock engaged. Engine speed cannot be control‐ led with the throttle trigger in this position.
English 4 Working Techniques erwise the cutting attachment may stick in the cut or kick back – risk of injury! Preparing for felling Make sure no-one is endangered by the falling tree – the noise of your engine may drown any warning calls. 1 ► 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).
4 Working Techniques English 001BA146 KN 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. – Carefully clear the base of the trunk (e.g., with an axe) – sand, stones and other foreign objects will blunt the saw chain – Remove largest buttresses: first the largest buttress – saw first vertically, then horizontally – only if the tree is in sound condition 4.
English 4.4 4 Working Techniques Sapwood cuts – With rotten trunks, leave a wider strip Sapwood cuts in long-fibered softwood help pre‐ vent sapwood splintering when the tree falls. Make cuts at both sides of the trunk at same height as bottom of 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. 4.
4 Working Techniques English damage the saw chain and cause dangerous kickback. Select suitable felling wedges dependent on the trunk diameter and the width of the kerf (ana‐ logue to felling cut (E)). Contact the STIHL dealer for the selection of the felling wedge (suitable length, width and height). 4.6 Selecting the appropriate felling cut Shout a warning before starting the felling cut.
English 4 Working Techniques ► Make the felling cut towards the holding strap (2) – Cut horizontally – Do not cut into the holding strap. ► Make the felling cut up to the stabilizing strap (3) – Do not cut into the stabilizing strap The felling cut must be continued on the oppo‐ site side of the trunk. 001BA266 KN Ensure that the second cut is at the same level as the first cut.
5 Cutting Attachment English 5.1 Chain Scabbard 001BA268 KN 001BA244 KN ► Tip of the guide bar must penetrate the wood before the holding strap (4) – guide the chain‐ saw absolutely horizontally and swivel as widely as possible ► Make the felling cut up to the hinge (5) – Do not cut into the hinge ► Make the felling cut up to the holding strap (6) – Do not cut into the holding strap. Shout a second warning immediately before the tree falls.
7 Mounting the Bar and Chain (quick chain tensioner) ► Turn the screw (1) counterclockwise until the tensioner slide (2) butts against the left end of the housing slot. 6.2 Disengage the chain brake. ► 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" 001BA186 KN 7 7.
7 Mounting the Bar and Chain (quick chain tensioner) 7.4 ► Remove screw (2) English Fitting the saw chain 3 2310BA016 KN 1 ► Position tensioning gear (1) and guide bar (3) relative to one another 2 ► Insert and tighten screw (2) WARNING Releasing the chain brake Put on protective gloves – risk of injury by the sharp cutters. 001BA186 KN 7.
8 Tensioning the Saw Chain (side chain tensioner) 8 Tensioning the Saw Chain (side chain tensioner) 142BA063 KN English 135BA011 KN 1 ► Guide the drive link into the bar groove (see arrow) and turn the tensioning gear to the left as far as possible ► Fit chain sprocket cover, sliding the guide lugs into the engine housing openings Tensioning the Saw Chain (quick chain tensioner) 1 2 001BA112 KN When fitting the chain sprocket cover, the teeth of the adjusting wheel and the tensioning gear must mes
10 Checking Chain Tension English 11.2 ► Check chain tension frequently – see chapter on "Operating Instructions". 10 NOTICE Checking Chain Tension Unsuitable fuels or a mixing ratio that deviates from the specification can lead to severe engine damage. The engine, seals, fuel lines and fuel tank may be damaged if low-quality gasoline or engine oil is used. 142BA064 KN 11.2.1 ► Shut off the engine. ► Wear work gloves to protect your hands.
English 12 Fueling Fuel mixture deteriorates with age – mix only as much as needed for a few weeks. Do not store fuel mixture for longer than 30 days. The fuel mixture can become unusable more quickly if exposed to light, sunlight or low or high tempera‐ tures. 12.2 Opening WARNING 001BA236 KN STIHL MotoMix however can be stored for up to 5 years without any problems. ► Shake the canister containing the fuel mixture thoroughly before refueling ► Raise grip to vertical position.
12 Fueling 12.3 English Filling Up with Fuel Take care not to spill fuel while fueling and do not overfill the tank. 12.4 001BA235 KN STIHL recommends you use the STIHL filler noz‐ zle for fuel (special accessory). ► Fill the fuel tank. Closing 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. 001BA241 KN 001BA234 KN ► Fold the grip down. Tank cap is locked. 12.
English 13 Chain Lubricant WARNING 001BA239 KN Do not use waste oil. Renewed contact with waste oil can cause skin cancer. Moreover, waste oil is environmentally harmful. ► Place the cap on the opening and rotate it counterclockwise until it engages the filler neck. ► Continue rotating the cap counterclockwise (about a quarter turn) – this causes the bottom of the cap to be turned to the correct position. ► Turn the cap clockwise and lock it in position – see section on "Closing".
15 Checking Chain Lubrication Checking Chain Lubrica‐ tion due to kickback: Saw chain is blocked - and stops running. 16.2 Disengage the chain brake. The saw chain must always spin off a small amount of oil. ► Pull the hand guard back towards the front handle. NOTICE Never operate your machine without chain lubri‐ cation. If the saw chain runs dry, the cutting attachment may very quickly be damaged beyond repair. Before starting work, always check the chain lubrication and oil level in the tank.
English 17 Winter Operation Part-time use: occasional use: 17 17.1 every six months annually In case of erratic idling behavior or poor acceler‐ ation ► Turn the low speed screw (L) 1/4 turn counter‐ clockwise Winter Operation 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". Pre-heating carburetor ► Remove the shroud – see "Shroud" 17.1.1 17.
18 Starting / Stopping the Engine 18.2 Setting the Master Control Lever English 18.4.1 On the ground To move the Master Control lever from the nor‐ mal run position (F) to choke closed (l), press down the throttle trigger lockout and squeeze the throttle trigger at the same time and hold them in that position – now set the Master Control lever. To select the starting throttle position (n), move the Master Control lever to choke closed (l) first, then push it into the starting throttle posi‐ tion (n).
English 18.4.2 18 Starting / Stopping the Engine Between knees or thighs ► Pull the starter grip slowly with your right hand until you feel it engage – and then give it a brisk strong pull and push down the front han‐ dle at the same time. Do not pull out the starter rope to full length – it might otherwise break. Do not let the starter grip snap back. Guide it slowly back into the housing so that the starter rope can rewind properly.
18 Starting / Stopping the Engine 18.6.1 English 18.7 Versions with manual fuel pump When engine begins to fire STOP 0 2310BA003 KN 2310BA021 KN 4 ► Press the manual fuel pump bulb at least five times – even if the bulb is already filled with fuel. ► Set the Master Control lever (4) to the starting throttle position (n). ► Hold and start your saw as described. 18.6.2 18.
English 19 Operating Instructions NOTICE Always disengage chain brake before accelerat‐ ing the engine. High revs with the chain brake engaged (chain locked) will quickly damage the clutch and chain brake. 18.9 At very low outside tempera‐ tures ► Allow engine to warm up at part throttle. ► Change over to winter operation if necessary – see “Winter Operation”. 18.10 Stopping the engine ► Move the Master Control lever to the stop position (0). 18.
20 Taking Care of the Guide Bar English 21 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. 19.3.1 21.1 Shroud Remove shroud ► Move the Master Control Lever to the stop position 0 ► Push the front hand guard forwards – the saw chain is blocked Short-term storage 1 Wait for engine to cool down.
English 22.2 23 Cleaning the Air Filter HD2 Filter 23.1.1 Removing the Air Filter (round filter) NOTICE 5902BA008 KN To avoid damaging the filter, do not use tools for removing and installing the air filter. – HD2 filter (black filter frame, pleated filter material) for extreme wintry conditions (e.g. powder or drifting snow) or very dusty work areas. 2. Synthetic Fiber/Fleece Filter ► Rotate the air filter a 1/4 turn counterclockwise and lift it away in the direction of the rear han‐ dle.
24 Adjusting the Carburetor English ► Reinstall the air filter. 23.1.4 ► Turn the low speed adjusting screw (L) clock‐ wise until it is firmly in its seat – then back off 1/4 turn Installing the Air Filter (round filter) 24.3 Setting the idle speed 1. ► Place the air filter in position. ► Push the air filter in the direction of the filter housing and turn it clockwise at the same time until it engages – the "STIHL" name must be horizontal. ► Install the shroud – see "Shroud". 23.1.
English 25 Spark Plug ► Turn the high speed adjusting screw (H) slightly clockwise (leaner) – max. up to the stop Possible causes are: – Too much oil in fuel mix. – Dirty air filter. – Unfavorable running conditions. NOTICE After descending from a high altitude, restore the carburetor setting to the standard setting. 1 25 Spark Plug ► If the engine is down on power, difficult to start or runs poorly at idle speed, first check the spark plug.
27 Checking and Replacing the Chain Sprocket English ► Remove saw chain and guide bar; clean and spray with protective oil ► Thoroughly clean the machine - pay special attention to the cylinder fins and air filter ► When using biological chain oil (e.g.
English 28.1 Maintaining and Sharpen‐ ing the Saw Chain The diameter of file to be used depends on the chain pitch – see table "Sharpening tools". Sawing effortlessly with a prop‐ erly 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.
28 Maintaining and Sharpening the Saw Chain File holder 689BA025 KN 90° 689BA018 KN 28.4 English ► 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. To check the angles 001BA203 KN 28.
English 28.7 28 Maintaining and Sharpening the Saw Chain Depth gauge setting mark) is lowered at the same time as the depth gauge of the cutter. WARNING a 689BA023 KN 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 The depth gauge determines the depth to which the cutter penetrates the wood and thus the chip thickness.
29 Maintenance and Care English ► Lay the file gauge on the saw chain – the high‐ est point of the depth gauge must be flush with the file gauge ► After sharpening, clean the saw chain thor‐ oughly, 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 condi‐ tion Sharpening tools (special accessories) Chain pitch Round file Round file File holder File gauge Taper square Sharpening file ^ set1) Inches
Manual fuel pump (if present) check Have repaired by a specialist dealer1) Fuel pick-up body / filter in fuel check tank Clean, replace filter insert replace Fuel tank Clean Lubricating oil tank Clean Chain lubrication check Saw chain Check, pay attention to sharpness Checking the chain tension sharpen Guide bar Check (wear, damage) Clean and turn over Deburr replace Chain sprocket check Air filter Clean replace Anti-vibration elements check Have replaced by servicing dealer1) Air intake on fan housing Cle
Accessible screws and nuts (except adjusting screws) Chain catcher Safety information label 30 check replace replace Minimize Wear and Avoid Damage 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, oper‐ ating and maintenance instructions in this man‐ ual.
English 31 Main Parts – Starter mechanism – Spark plug – Components of antivibration system 31 18 Front handle (handlebar) 19 Spark plug boot 20 Starter grip Main Parts 21 Fuel filler cap 22 Master Control lever 23 Throttle trigger 13 7 24 Throttle trigger lockout 14 25 Rear handle 3 2 1 26 Rear hand guard # 4 5 6 11 9 7 32 12 8 18 17 # Serial number 10 32.1 Specifications Engine STIHL single cylinder two-stroke engine 20 19 1 21 15 22 32.1.1 24 25 23 26 Idle speed:1) 32.
33 Ordering Spare Parts Oil tank capacity: 32.5 English Weight dry, without bar and chain MS 231: MS 231 C with ErgoStart and quick chain tensioner: MS 251: MS 251 C with ErgoStart and quick chain tensioner: 32.6 32.7.2 200 cc (0.2 l) 4.8 kg 5.1 kg Actual cutting length may be less than the speci‐ fied length 32.6.1 .325" Rollomatic E guide bars Cutting lengths: Pitch: Groove width: Nose sprocket: 32.6.2 32.6.3 35, 40, 45 cm .325" (8.25 mm) 1.
English 34 Maintenance and Repairs Model Contact your STIHL servicing dealer for the lat‐ est information on waste disposal. Serial number 36 Guide bar part number ANDREAS STIHL AG & Co. KG Badstr. 115 D-71336 Waiblingen Chain part number 34 Germany Maintenance and Repairs declare in exclusive responsibility that the prod‐ uct 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.
36 EC Declaration of Conformity English ANDREAS STIHL AG & Co. KG Produktzulassung (Product Licensing) The year of manufacture and serial number are applied to the product. Done at Waiblingen, 03.02.2020 ANDREAS STIHL AG & Co. KG p p. Dr.
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