Stihl Ms 250 C Manual
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MS 250 English 29 STIHL MotoMix uses STIHL HP Ultra two-stroke engine oil suited for high performance engines. For further details, see www.STIHLusa.com/ethanol If not using MotoMix, use only STIHL two-stroke engine oil or equivalent high- quality two-stroke engine oils that are designed for use in air cooled two-cycle engines. The use of non-seasonal gasoline blends may increase the potential for pressure to build in the fuel tank during operation. For example, using a winder blend during the summer will increase pressure in the fuel tank. Always use gasoline blends appropriate to the season, altitude and other environmental factors. Do not use BIA or TCW rated (two- stroke water cooled) mix oils or other mix oils that state they are for use in both water cooled and air cooled engines (e.g., outboard motors, snowmobiles, chain saws, mopeds, etc.). WARNING Take care when handling gasoline. Avoid direct contact with the skin and avoid inhaling fuel vapor. When filling at the pump, first remove the container from your vehicle and place the container on the ground before filling. To reduce the risk of sparks from static discharge and resulting fire and/or explosion, do not fill fuel containers that are sitting in or on a vehicle or trailer. The container should be kept tightly closed in order to limit the amount of moisture that gets into the mixture.The machine‘s fuel tank should be cleaned as necessary. Fuel mix ages If not using MotoMix, only mix sufficient fuel for a few days of work, not to exceed 30 days of storage. Store in approved fuel-containers only. When mixing, pour oil into the container first, and then add gasoline. Close the container and shake it vigorously by hand to ensure proper mix of oil and gasoline. Dispose of empty mixing-oil containers only at authorized disposal locations. Preparations NBefore fueling, clean the filler cap and the area around it to ensure that no dirt falls into the tank. Always thoroughly shake the mixture in the canister before fueling your machine. NPosition the machine so that the filler cap is facing up. WARNING In order to reduce the risk of fire and other personal injury from escaping gas vapor and fumes, remove the fuel filler cap carefully so as to allow any pressure build-up in the tank to release slowly Gaso- lineOil (STIHL 50:1 or equiva- lent high-quality oils) US gal. US fl.oz. 12.6 2 1/2 6.4 5 12.8 Fueling 001BA229 KN
MS 250 English 30 Opening NRaise handle. NTwist filler cap counterclockwise (approx. 1/4 turn). Markings on filler cap and housing must align.NRemove the filler cap. Refueling Take care not to spill fuel while fueling and do not overfill the tank – leave approx. 1/2" (13 mm) air space. Closing Handle is in an upright position: NPosition filler cap – markings on filler cap and housing must align. NPush the filler cap down as far as it will go.NPush the filler cap down and twist it clockwise until it engages. Then the markings on filler cap and housing will align. NFlip the handle down. 001BA236 KN 001BA232 KN 001BA234 KN 001BA237 KN 001BA234 KN 001BA233 KN 001BA231 KN 001BA235 KN
MS 250 English 31 Filler cap is now closed. If the filler cap will not engage into the tank housing The base of the filler cap is rotated in relation to the upper part. NLook at the black alignment marks on the top of the filler cap.NWith the filler cap in the filling neck, twist it counterclockwise until it drops into its seat. NContinue to twist the filler cap counterclockwise (approx. 1/4 turn) – this will twist the base of the cap into the correct position. NWhile pushing down on the cap, twist the filler cap clockwise and close it – see section "Closing."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. NOTICE 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. WARNING Do not use waste oil. Renewed contact with waste oil can cause skin cancer. Moreover, waste oil is environmentally harmful. NOTICE Waste oil does not have the necessary lubricating properties and is unsuitable for chain lubrication. Left: Base of filler cap is rotated – interior marking (1) is aligned with the exterior marking. Right: Base of filler cap is in the cor- rect position – interior marking is below the clip. It does not align with the exte- rior marking. 001BA241 KN 1 001BA238 KN 001BA239 KN &KDLQ/XEULFDQW
MS 250 English 32 Preparations NThoroughly clean the oil filler cap and the area around it to ensure that no dirt falls into the tank. NPosition the machine so that the filler cap is facing up. NOpen the filler cap. Filling chain oil tank NRefill the chain oil tank every time you refuel. Take care not to spill chain oil while refilling and do not overfill the tank. NClose the filler cap. There must still be a small amount of oil in the oil tank when the fuel tank is empty. 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. The saw chain must always throw off a small amount of oil. NOTICE 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 check 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". Filling Chain Oil Tank 001BA158 KN &KHFNLQJ&KDLQ/XEULFDWLRQ 143BA024 KN
MS 250 English 33 Locking chain with chain brake –in an emergency –when starting –at idling speed The chain is stopped and locked when the hand guard is pushed toward the bar nose by the left hand – or when brake is activated by inertia in certain kickback situations. Releasing the chain brake NPull the hand guard back toward the front handle. NOTICE Always disengage chain brake before accelerating engine and before starting cutting work. The only exception to this rule is when you check operation of the chain brake. High revs with the chain brake engaged (chain locked) will quickly damage the powerhead and chain drive (clutch, chain brake). The chain brake is designed to be activated also by the inertia of the front hand guard if the forces are sufficiently high. The hand guard is accelerated toward the bar nose - even if your left hand is not behind the hand guard, e.g. during a felling cut. The chain brake will operate only if it has been properly maintained and the hand guard has not been modified in any way. Check operation of chain brake Before starting work: Run engine at idle speed, engage the chain brake (push hand guard toward bar nose). Accelerate up to full throttle 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, such as your STIHL servicing dealer, at the following intervals: Chain Brake 143BA011 KN 143BA012 KN )XOOWLPHXVDJH HYHU\ PRQWKV 3DUWWLPHXVDJH HYHU\ PRQWKV 2FFDVLRQDOXVDJH HYHU\ PRQWKV
MS 250 English 34 At temperatures below +50°F (+10°C): NSqueeze the throttle trigger lockout and move the Master Control lever to l (cold start). NTurn the knob above the rear handle 90° counterclockwise. NLift off the carburetor box cover vertically.NLift out the shutter (in front of spark plug) vertically. NTurn the shutter 180°. NRefit the shutter. NRefit the carburetor box cover and secure it with the knob. Heated air is now drawn in from around the cylinder to warm the carburetor – this helps prevent carburetor icing. NOTICE At temperatures above +70 °F (+ 20°C), always close the shutter again. This is necessary to avoid engine running problems and overheating. Positions of Master Control Lever Stop 0 – engine off – the ignition is switched off Normal run position(F) – engine runs or can fire. Starting throttle(n) – this position is used to start a warm engine. The Master Control lever moves to the normal run position as soon as the throttle trigger is squeezed. Choke shutter closed(l) – this position is used to start a cold engine. Winter Operation 208BA005 KN135BA029 LÄ 6WDUWLQJ6WRSSLQJWKH (QJLQH STOP 0 001BA140 KN
MS 250 English 35 Setting the Master Control Lever To move the Master Control lever from the normal 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 position (n). The Master Control lever must be in the choke closed position (l) for the changeover to the starting throttle position (n). The Master Control lever moves from the starting throttle position (n) to the run position (F) when you press down the throttle trigger lockout and blip the throttle trigger at the same time. To switch off the engine, move the Master Control lever to Stop (0). Choke shutter closed (l) –if the engine is cold –if the engine stalls when you open the throttle after starting. –if the fuel tank was run until empty (engine stopped). Starting throttle position (n) –if the engine is warm, i.e. if it has been running for about one minute. –after engine begins to fire, –after clearing a flooded combustion chamber.Manual fuel pump Press the manual fuel pump bulb several times – even if the bulb is already filled with fuel: –When starting for the first time. –if the fuel tank was run until empty (engine stopped). Holding the Saw There are two ways of holding the saw when starting.On the ground NPlace your saw on the ground. Make sure you have a firm footing – check that the chain is not touching any object or the ground. NHold the saw firmly on the ground with your left hand on the front handle – your thumb should be under the handle. NPut your right foot into the rear handle and press down. 143BA018 KN
MS 250 English 36 Between knees or thighs NHold the rear handle tightly between your legs, just above the knees. NHold the front handle firmly with your left hand – your thumb should be under the handle. Cranking NPull 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 handle 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. Machines without additional manual fuel pump: If the engine is new or after a long out-of-service period, it may be necessary to pull the starter rope several times to prime the fuel system.Starting the Saw WARNING Bystanders must be well clear of the general work area of the saw. NObserve safety precautions. Versions with manual fuel pump NPress the manual fuel pump bulb at least five times – even if the bulb is already filled with fuel. 143BA019 KN 143BA020 KN 135BA027 KN
MS 250 English 37 Versions with decompression valve NPress in the button to open the decompression valve. The decompression valve closes as soon as the engine fires. NFor this reason you must press in the button before each starting attempt.All models NPush the hand guard (1) forward – the chain is locked. NPress down the trigger lockout (2) and pull the throttle trigger at the same time. Set Master Control lever (3) to: Choke shutter closed (l) –if the engine is cold (also use this position if the engine stopped when you opened the throttle after starting) Starting throttle position (n) –if the engine is warm, i.e. if it has been running for about one minute. NHold and start your saw as described. When engine begins to fire NSet the Master Control lever to the starting throttle position (n ). NHold and start your saw as described. As soon as the engine runs NPress down trigger lockout and the blip the throttle trigger (4) – the Master Control lever (3) moves to the run position (F) and the engine settles down to idling speed. NOTICE As the chain brake is still engaged, the engine must be returned to idling speed immediately – or the engine housing and chain brake might otherwise be damaged. 135BA015 KN 2 1 208BA000 KN 0 3 3 45 0 208BA001 KN
MS 250 English 38 NPull the hand guard back toward the front handle. The chain brake is now disengaged – your saw is ready for operation. NOTICE Always disengage chain brake before accelerating the engine. High revs with the chain brake engaged (chain locked) will quickly damage the clutch and chain brake. At very low outside temperatures NAllow engine to warm up at part throttle. Stopping the Engine NMove the Master Control lever to the stop position (0). If engine does not start If you did not move the Master Control lever from the choke closed position (l) to the starting throttle position (n) quickly enough after the engine began to fire, the combustion chamber may be flooded. NMove the Master Control lever to the stop position (0). NRemove the spark plug – see "Spark Plug". NDry the spark plug. NCrank the engine several times with the starter to clear the combustion chamber. NRefit the spark plug – see "Spark Plug". NSet Master Control lever to the starting throttle position (n) – even if the engine is cold. NNow start the engine. During the break-in period A factory new machine should not be run at high revs (full throttle off load) for the first three tank fillings. This avoids 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 NOTICE Do not make the mixture leaner to achieve an apparent increase in power – this could damage the engine – see "Adjusting the Carburetor". NOTICE 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. 143BA012 KN 2SHUDWLQJ,QVWUXFWLRQV