Question 1

can i pressure wash my stihl ms 250 to get all the sap and gunk off?

Accepted Answer

No. Do not use a high-pressure cleaner. The hard jet of water will force moisture into the carburetor, ignition system, bearings, and fuel tank, causing corrosion and serious damage. Correct cleaning method:Clean plastic parts with a cloth. Avoid harsh detergents. Clean dust and dirt off the machine with a brush or damp cloth. Do not use grease solvents. Clean the ventilation slots and cylinder fins with a brush or compressed air to maintain cooling. For sap, use a plastic scraper and a rag dampened with a mild solvent like mineral spirits, but keep it away from plastic parts and labels. If the machine is very dirty, disassembly for proper cleaning by a dealer is safer than risking water damage with a pressure washer. Heads up: Always clean your saw after use, especially the guide bar and air filter. Built-up debris is the main cause of overheating and premature wear. Store it clean and dry.

Question 2

how often do i need to sharpen the chain on my stihl ms 250? i'm just cutting firewood

Accepted Answer

Sharpen the chain as soon as you notice it's taking more effort to push through the wood or it's producing fine dust instead of chips. For regular firewood cutting, you might need to touch it up every couple of hours of actual cutting time. Here's the full maintenance routine for the cutting attachment: Every time you refuel: Check chain tension and sharpness. Every time you sharpen or replace the chain: Turn the guide bar over to prevent one-sided wear, especially at the nose. Regularly: Clean the bar's oil inlet hole, oilway, and bar groove. Deburr the bar if needed. If you're cutting dirty or sandy wood, you'll need to sharpen much more frequently. Dull chains are dangerous, as they increase the risk of kickback. Under normal conditions, check and sharpen the saw chain as part of your daily checks. If you use it only occasionally, you can extend the intervals, but always do a visual inspection before starting.

Question 3

stihl ms 250 making a high-pitched whining noise when i rev it, chain isn't moving

Accepted Answer

The clutch drum or chain sprocket is spinning without engaging the chain. The chain brake is likely engaged. Disengage the chain brake by pulling the hand guard toward the front handle. The chain should rotate when you press the throttle. If the chain brake is disengaged and the chain still doesn't move, inspect the drive components.Check the chain tension. An overly tight chain at operating temperature can damage the crankshaft and bearings. Check the chain sprocket for wear. A worn sprocket won't drive the chain properly. Check the guide bar groove depth. If it's less than 6.0 mm for a 3/8" chain, the drive links are scraping and the chain won't ride correctly. If that didn't work, the clutch springs may be worn or the clutch shoes are contaminated with oil. This requires inspection by a specialist dealer. Heads up: That whining is the engine spinning without a load. Don't hold it at high rpm like that for more than a few seconds. It leads to overheating.

Question 4

my stihl ms 250 is leaking bar and chain oil all over my garage floor, not just when it's running

Accepted Answer

Yeah, this one's common. First, make sure the oil tank cap is on tight and the seal is intact. If it's loose, it'll leak. The cap is labeled for the oil tank. If the cap is tight, the leak is probably from the bar oiling system. Check a few things:The oil inlet hole on the guide bar. The oilway inside the saw where the bar mounts. The bar groove itself. Clean all these areas. Sawdust and crud can clog the system, causing oil to back up and leak from the seals. Use a stiff brush or compressed air—don't use grease solvents. If that didn't work, the oil pump might be faulty or there's a bad seal. That's a job for a STIHL servicing dealer. Don't try to modify or repair the oil system yourself. Heads up: Always store the saw with empty fuel and oil tanks if it's going to be sitting for a while. Prevents leaks and fuel system issues.

Question 5

how do i clean the air filter on my stihl ms 250? it's absolutely caked in sawdust

Accepted Answer

Remove the air filter and wash it. Clean it every time you refuel and replace it after every 25 hours of operation. Wash the filter in a clean, non-flammable solution like warm soapy water. Do not use harsh detergents; they can damage the material. Let the filter dry completely before reinstalling. While it's out, clean the air intake on the fan housing. If performance is still poor after cleaning, the filter might be damaged and need replacement. Also check the cylinder fins for clogging; clean them if necessary. Heads up: Working in extremely dusty conditions means you need to clean the air filter more often. A clogged filter is the most common cause of power loss and hard starting.

Question 6

can i use my stihl ms 250 in the winter? it was like 20 degrees out and it kept stalling

Accepted Answer

Yes, but you need to switch it to winter operation mode to prevent carburetor icing. The setting is for temperatures below +10°C (50°F). Procedure:Remove the carburetor box cover. Lift out the intake air shutter (located in front of the spark plug) vertically. Turn the shutter 180 degrees. Refit the shutter and reinstall the carburetor box cover. This draws heated air from around the cylinder to warm the carburetor. If that didn't work: Ensure you're using the correct fuel mix. Also, after a long period of full-throttle operation, allow the engine to run at idle speed so heat can dissipate. This protects the ignition and carburetor from thermal overload. Critical note: At temperatures above +20°C (68°F), you must close the shutter again. Leaving it open in warm weather causes engine running problems and overheating.

Question 7

stihl ms 250 chain keeps coming loose while i'm cutting, i tighten it and five minutes later it's sagging again

Accepted Answer

The chain is stretching because it's new. A new saw chain must be retensioned more frequently. Check tension with the chain cold and the engine off. Fix: Correct tension is when the chain fits snugly against the underside of the bar but you can still pull it along the bar by hand. Use the side or quick chain tensioner to adjust. Run the saw at idle for a minute to spread oil, then recheck. You will need to do this several times during the first tank of fuel. If that didn't work: The guide bar groove may be worn out. Check the groove depth. For a 3/8" pitch chain like yours, the minimum groove depth is 6.0 mm. If it's less, replace the guide bar. Also, regularly clean the oil inlet hole, the oilway, and the bar groove to ensure proper lubrication and reduce friction. Heads up: After a long period of full-throttle operation, let the engine idle to cool down. A hot chain stretches more. And always slacken the chain when you're done if you retensioned it while it was hot.

Question 8

how tight should the chain be on my stihl ms 250? i feel like i'm always adjusting it.

Accepted Answer

It should be snug against the bar, but still pull freely by hand. Let me explain the right way to check and adjust it. First, always adjust the chain tension with the saw cold. A hot chain expands and will be too tight if you set it warm. Here's the process: Loosen the two nuts on the side cover (the bar nuts). Just crack them loose—don't remove them. Lift the tip of the bar up to take slack out of the chain. Turn the tensioning screw (located near the front of the saw, just ahead of the bar) clockwise until the chain is snug against the underside of the bar. Now, check the tension. You should be able to pull the chain away from the bar, midway between the tip and the saw body, just enough to see the bottom of the drive link. The drive link should not come completely out of the bar groove. While holding the bar tip up, tighten the two bar nuts securely, alternating between them. If you're constantly adjusting, the chain is stretching because it's new—that's normal for the first few tanks of fuel. If an older chain keeps loosening, it's worn out and needs replacement. Also, a dull chain creates more friction and heat, causing more expansion and slack. A final tip: Always check chain tension before each use, and re-tighten as needed with the saw cold.

Question 9

stihl ms 250 makes a high-pitched squealing noise when i first start it, goes away after a minute. normal?

Accepted Answer

Yeah, that's a classic sound—usually the clutch bearing. It's dry when cold. The clutch drum rides on a needle bearing. If it doesn't have enough grease, or the grease has dried out, you get that metal-on-metal squeal on startup until friction warms it up. Here's the fix: you need to grease the clutch bearing. Remove the bar and chain (loosen the nuts on the side cover). Pull off the clutch drum (the sprocket the chain rides on). You might need a special tool to hold the clutch, but sometimes you can just pull it off. Inside the center of the drum, you'll see the bearing. Pack high-temperature bearing grease into the bearing cavity. Don't glob it on the outside. Reassemble. The squeal should be gone. If that didn't work, the clutch springs might be weak or the clutch shoes could be worn, causing drag and noise. That's a parts replacement job. Heads up: Do this regularly as part of maintenance, like when you sharpen the chain. A squealing bearing is a wearing bearing. If you ignore it, it'll fail completely and lock up.

Question 10

can i use regular car motor oil for the bar oil on my stihl ms 250? i ran out of the stihl stuff.

Accepted Answer

No. Do not use car motor oil. Car oil is not formulated for chainsaw bar and chain lubrication. It lacks the tackifiers that make bar oil stick to the chain at high speed. It will sling off, causing rapid chain and bar wear, overheating, and increased risk of kickback. It can also damage the oil pump seals. Use only a dedicated chainsaw bar oil. In a genuine emergency, a biodegradable vegetable oil is a better temporary substitute than motor oil, but performance will still be poor. If you're asking because the oiler seems clogged, that's a different fix. Clean the oil outlet on the saw and the bar groove. Use only proper bar oil to prevent future clogs. Heads up: The right oil is a safety feature. A poorly lubricated chain binds, kicks back more easily, and can snap. Keep a bottle of STIHL or equivalent bar oil on hand.

Question 11

the chain on my stihl ms 250 won't stop spinning when the engine is at idle, even with the chain brake off. is that dangerous?

Accepted Answer

Yes. This is dangerous and indicates an incorrect idle speed adjustment. The chain must be stationary at idle. Cause: Engine idle speed is set too high. Fix: Adjust the idle speed screw (marked 'LA' on the carburetor). Start the engine and let it warm up for several minutes. With the chain brake OFF, check if the chain is moving. If it is, proceed. Locate the idle speed screw (LA). Using a small screwdriver, turn it counterclockwise in small increments (1/8 turn at a time). Wait a few seconds after each adjustment. Stop when the chain stops moving. The engine should now idle steadily without stalling. If that didn't work, the clutch may be worn or gummed up with sawdust, causing it to drag. This requires disassembly and cleaning by a qualified technician. Heads up: Never operate the saw with a rotating chain at idle. It violates basic safety protocol. If you are not confident making this adjustment, take the saw to a STIHL servicing dealer.

Question 12

my stihl ms 250 is leaking bar oil all over my garage floor, even when it's just sitting. common problem?

Accepted Answer

Yeah, this one's common. It's usually not a catastrophic failure, just how the oiler system works when the saw is stored wrong. The bar oil tank is vented. If you store the saw flat on its side, or with the bar nose lower than the tank, oil can siphon out through the oiling hole in the bar. First fix: always store the saw with the bar pointing up, or lay it on its side with the bar and oil tank facing up. If it's still leaking while stored correctly, check the oil cap seal. Make sure the cap is on tight and the rubber gasket isn't cracked or missing. If that didn't work, the oil pump itself might be faulty, but that's less likely. A more probable cause is a clog in the oil passage from the tank to the bar. You can try cleaning the oil outlet hole on the saw body and the matching hole on the bar with a thin wire. Heads up: Use the right bar oil, not motor oil. Thinner oils leak more easily. And that pool of oil on the floor? It's a fire hazard and a slipping hazard. Clean it up.

Question 13

how do i sharpen the chain on my stihl ms 250? feels like it's just rubbing now instead of cutting.

Accepted Answer

Your cutters are dull. You need to file them. Here's the fastest way. Secure the saw: Engage the chain brake. Clamp the bar in a vise. Match the file: Use a round file that matches your chain's pitch. For the MS 250, that is a 5/32" or 13/64" file. Set the guide: Use a filing guide that sets the correct filing angle, which is usually 30 degrees, and ensures the correct depth gauge setting. Now, file each cutter: Place the guide over the cutter. File with smooth, forward strokes, applying even pressure. File from the inside of the cutter toward the outside. Give each cutter the same number of strokes, typically 2-3. After sharpening all cutters on one side, rotate the saw and repeat for the other side. If that didn't work, your depth gauges are too high. They need to be filed down with a flat file and a depth gauge tool. If the chain is badly worn or damaged, just replace it. Heads up: Always wear gloves. A sharp chain cuts faster and is safer than a dull one that forces you to push.

Question 14

stihl ms 250 keeps dying as soon as i give it gas, runs fine at idle. anyone else have this?

Accepted Answer

This usually means the engine isn't getting enough fuel when you open the throttle. Let's walk through it step-by-step. First, you'll want to check the air filter. A dirty filter chokes the engine. Remove it, tap it clean, or wash it if it's the felt type. Let it dry completely before putting it back. If the filter is clean, the issue is likely in the fuel system. Here's what to do: Drain the fuel tank completely. Old fuel goes bad and gums things up. Refill with fresh, properly mixed fuel. Use the exact oil-to-gas ratio specified for your saw. Check the fuel filter inside the tank. If it's dark or clogged, it needs to be replaced. If that didn't work, the carburetor's high-speed circuit might be clogged or out of adjustment. This requires a special tool and some know-how. If you're not comfortable, this is the point to take it to a STIHL dealer for service. A quick tip: Always use fresh fuel mix, and run the saw dry if you're storing it for more than a month to prevent this.

Question 15

my stihl ms 250 chainsaw won't start, pulled the cord like 20 times and nothing. what's wrong?

Accepted Answer

The engine is flooded or the ignition system is blocked. Check three things, in this order. Set the master control lever to the STOP position. Pull the starter rope 5-6 times with the throttle trigger locked. This clears a flooded engine. Move the master control lever to the cold start position (choke). Engage the chain brake for safety. Pull the starter rope until the engine fires, then immediately move the master control lever to the warm start/half-throttle position. Pull again to start. If it still won't start, the spark plug is likely fouled. Remove it, clean the electrode, check the gap, and try again. If that didn't work, the fuel in the tank is old or the fuel filter in the tank is clogged. Drain and replace with fresh, properly mixed fuel. A clogged air filter will also prevent starting—clean it. Heads up: Always use the chain brake when starting. Never drop-start the saw. If you've gone through these steps and it still won't fire, the carburetor may need service.

Question 16

stihl ms 250 runs fine then suddenly bogs down and dies in cold weather, like below freezing.

Accepted Answer

This is carburetor icing. Moisture in the intake air freezes on the carburetor throttle plate, blocking fuel flow. The MS 250 has a winter operation mode to prevent this. For temperatures below +10°C (50°F), you need to open the intake air shutter.Remove the carburetor box cover (the plastic shroud near the spark plug). Lift out the shutter vertically. It's a small metal or plastic plate in front of the spark plug. Turn the shutter 180 degrees. Refit the shutter and reinstall the carburetor box cover, securing it with the knob. This allows the engine to draw in heated air from around the cylinder to warm the carburetor. If that didn't work: Ensure you are using fresh fuel mix. Old gas absorbs water, which exacerbates icing. Also, check that the air filter is clean and dry. A saturated filter can introduce more moisture. Heads up: This setting is for cold weather only. At temperatures above +20°C (68°F), you must close the shutter again. Running with the winter shutter open in warm weather causes engine running problems and overheating.

Question 17

my stihl ms 250 guide bar is wearing out really fast on one side, what gives?

Accepted Answer

One-sided wear is caused by not rotating the bar and improper chain sharpening. The fix is simple and preventative. Every time you sharpen the chain, and every time you replace the chain, you must turn the guide bar over. Flip it so the top side becomes the bottom. This ensures even wear on both bar rails and the nose. Most bars have a direction arrow stamped on them; just make sure the arrow still points in the direction of chain rotation after you flip it. Also, check your sharpening technique. If you're consistently filing the cutters at an uneven angle or taking more material off one side of the chain, it will pull the bar and cause uneven wear. Use a filing guide to maintain consistent angles. If that didn't work: Measure the bar groove depth. With the filing gauge, check the depth in the area you use most for cutting. For a 3/8" pitch bar, the minimum groove depth is 6.0 mm. If it's less than that, the drive links are bottoming out. The cutters aren't riding on the bar rails correctly, causing rapid wear and poor cutting. At that point, you need to replace the guide bar. Heads up: Regular maintenance includes cleaning and turning over the bar, and deburring the rails. A worn bar will destroy a new chain quickly.

Question 18

stihl ms 250 chain oil tank is leaking, seems like it's coming from the cap. how do i seal it?

Accepted Answer

Leaks from the oil tank cap are usually due to a dirty seal, a cross-threaded cap, or a damaged O-ring. First, clean the area thoroughly. Wipe down the cap and the filler neck with a cloth to remove any sawdust or dirt. The sealing surfaces need to be clean. Check the inside of the cap for its rubber O-ring or gasket. Make sure it's present, flexible, and not cracked or deformed. Now, reseat the cap. Align it carefully with the threads on the tank. Turn it clockwise by hand until you feel it seat, then tighten it firmly but don't over-tighten, as that can damage the threads or the seal. Checking the fuel cap regularly for tightness is good practice for the oil cap too. If that didn't work: The leak might not be from the cap. Check the tank itself for cracks, especially if the saw was dropped. Also, check the oil outlet hole on the saw body where the bar mounts. Debris can clog the oilway, causing pressure to build and force oil past seals. Cleaning the oil inlet hole, oilway, and bar groove regularly is part of standard maintenance. Heads up: Use only proper chain oil or a recommended substitute. Using motor oil or other lubricants can damage the oil pump seals and cause leaks. If the cap seal is damaged, you'll need to get a replacement cap or O-ring from a STIHL dealer.

Question 19

can i use my stihl ms 250 to cut up an old pressure-treated fence post?

Accepted Answer

No. The machine is designed only to saw wood and wooden objects. Using it on pressure-treated lumber, which contains metals and chemicals, violates that intended use. Here's why it's a problem: Rapid Dulling: The chemicals and grit in treated wood will destroy your chain's cutting edges almost immediately. Contamination: Sawdust from treated wood is hazardous to breathe and can clog the air filter and cooling system with toxic dust. Accelerated Wear: The residue is highly abrasive and will prematurely wear out the guide bar groove, sprocket, and clutch. Voided Warranty: Using the saw for any other purpose increases the risk of accidents and voids your warranty coverage. If you need to cut treated wood: Use a dedicated demolition blade in a circular saw or reciprocating saw. They are designed for nail-embedded and abrasive materials. Heads up: Stick to clean, natural wood. If you've been cutting resinous lumber or under very dusty conditions, you need to shorten all your maintenance intervals—clean the air filter and cooling fins much more often.

Question 20

stihl ms 250 chain won't stop spinning when the engine is at idle, is this dangerous?

Accepted Answer

Yes. This indicates an incorrectly set idle speed. The chain must not rotate at idle. The cause is a carburetor idle adjustment that is set too high. This needs to be corrected immediately for safety. Fix:Ensure the saw is on a level surface and the chain brake is not engaged. Start the engine and let it warm up. With the throttle fully released, observe the chain. If it is moving, the idle speed is too high. The carburetor adjustment requires a special tool. Do not attempt to adjust it without the correct screwdriver. This is not a user-serviceable adjustment on this model. You must take it to a STIHL servicing dealer to have the idle speed set correctly. If that didn't work: A persistently high idle could also be caused by an air leak or a faulty throttle trigger mechanism. These also require inspection by a specialist dealer. Heads up: This is a critical safety issue. Do not use the saw until the idle is adjusted so the chain is stationary. A rotating chain at idle can cause loss of control and injury.

Question 21

my stihl ms 250 is smoking a lot and seems to run hot, is this normal?

Accepted Answer

No, that is not normal. A Stihl MS 250 smoking excessively and running hot typically indicates an airflow or cooling problem. The first and most likely culprit is a clogged air filter. A dirty filter chokes the engine, causing a rich fuel mixture, more smoke, and poor performance, which makes it work harder and overheat. Pull the filter cover off and inspect the foam filter. Clean it in warm soapy water, let it dry completely, and re-oil it if it's the oiled type. These filters should be replaced after every 25 hours of operation. Next, check the cylinder fins and the air intake on the fan housing. If they're packed with sawdust and debris, the engine can't cool itself. Clean them off with a brush or cloth. Never use a high-pressure washer, as the jet can force water into seals and bearings. If that didn't work: You might have the winter operation shutter in the wrong position. If it's above 20°C (68°F), that shutter in front of the spark plug should be closed for summer operation. If it's open, it draws in hot air from around the cylinder and can cause overheating and running problems. Heads up: After a long period of full-throttle cutting, always let the engine idle for a minute before shutting it off. This lets the cooling air flow dissipate the heat and protects engine components.

Question 22

stihl ms 250 chain keeps coming loose while i'm cutting, how do i fix this?

Accepted Answer

The chain is stretching as it heats up. You're not maintaining proper tension at operating temperature. Chain tension must be checked and adjusted frequently, especially on a new chain. Here's the procedure:Stop the engine and engage the chain brake. Check tension on the underside of the guide bar. The chain should fit snugly against the bar but you should still be able to pull it along by hand. If it sags, use the chain tensioner (side or quick, depending on your model) to tighten it. The drive links must not come out of the bar groove. If that didn't work: The guide bar groove may be worn out. Check the groove depth with a filing gauge. For a 3/8" pitch chain like yours, the minimum depth is 6.0 mm. If it's less, the drive link tangs are scraping the bottom and the chain can't seat properly. You need a new bar. Heads up: After a long session of cutting, if you tensioned the chain while it was hot, you must slacken it off before storing the saw. As the chain cools and contracts, excessive tension can damage the crankshaft and bearings.

Question 23

my stihl ms 250 chainsaw won't start when it's cold, what am i doing wrong?

Accepted Answer

This is almost always a fuel delivery or starting procedure issue. Let's walk through the cold start steps. First, make sure the chain brake is engaged. This locks the chain and is a safety requirement for starting. Locate the master control lever on the engine. Move it to the choke position (the snowflake symbol). If your model has a manual fuel pump, press the primer bulb at least five times, even if it looks full. This ensures fuel is in the carburetor. Now, place the saw on a firm, flat surface. Hold the front handle down with your left hand. With your right foot in the rear handle, pull the starter rope briskly until the engine attempts to fire (you'll hear a cough). At that point, immediately move the master control lever from the choke position to the half-throttle or fast idle position (the rabbit symbol). Pull the starter rope again. It should start. If it doesn't, go back to the choke position and repeat the priming and pulling process. If that didn't work: Check your fuel. It must be a fresh mix of gasoline and the correct 2-stroke engine oil. Old gas won't ignite properly. Also, check the spark plug. The electrode gap needs to be 0.5 mm. A fouled or damaged plug won't spark. Heads up: Once the engine is running, let it warm up at idle for a bit before you start cutting. This helps protect the ignition and carburetor from thermal overload.

STIHL MS 250 18-Inch Gas Chainsaw

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