I was having low power from my saw as I tried to figure out what was wrong. My saw is the same model as this one. I spent the day cleaning the carburetor and not cutting wood. I saw your video and checked the screen on the exhaust and found it to be plugged just like the one you showed in video. At first soap and water, that didn't work, tried alcohol, didn't work. I used Lucus injector cleaner, it worked well. Thanks for sharing the tip, it saved downtime and didn't need to take it in for repair at shop.
Of all the videos I have watched on chainsaw tuneups not a single one of them has mentioned this filter on the exhaust. Thank you for getting this information out there.
Instant results on my Stihl MS 180! I had changed the fuel filter, air filter, mixed fresh fuel, installed a new spark plug and then stripped and cleaned the carb but to no avail. Checked the spark arrestor screen after watching your video and found it to be plugged solid, just as in your video. Cleaned up the screen with some carb cleaner and now the saw runs like a charm. Certainly appreciate you sharing this tip for trouble shooting. Cheers.
Great advice on something I never thought to check. I have a similar model mine is the MS 250 and it is starting to bog a little occasionally so I'm going to check to see if mine has this screen as well. Thank you
My MS170 was only two years old and started bogging down at higher speed settings. Didn't think your fix would apply to such a new saw but it was the solution! Thanks for the great video!
Straight to the point! Well done, no music you didn't introduce us to your dog or your kids, though I am sure they are great but I just wanted to know how to tune my saw up and that's exactly what I got.
Thank you ! I'm a handyman guy and occasionally I've done some backyard mechanic stuff for over a half century. I've worked on all kinds of motors, but never had I come across a motor that uses some little screen over the exhaust. I had looked all over the internet to try to figure out why my small chainsaw was bogging down. Who would think there would be a little screen completely clogged with carbon. I cleaned it off and it's running great now, especially because I put a new spark plug in it. It's just a little Stihl ms150c that I use for cutting branches. Using my larger Stihl for that wears me out. Thanks again.
It’s also good to keep in mind never to run the saw too long or at all without that bar and chain on and tensioned properly. Not only could you over heat and over rev the engine but it can cause very expensive irreparable damage in the long run. Cheers!!
Speaking of the bar - flip the bar over everytime the chain gets removed. Helps keep the wearing of it distributed to both sides. When re-attaching the bar, put a slight upward pressure on the bottom of the tip of the bar while tightening the it.
What ‘very expensive irreparable damage’ would it cause? Why do you think the engine would overheat? You also can’t over rev the engine, short of just holding it wide open for a long time. Chainsaws are designed to rev, and newer ones all have limiters in the ignition. It’s a 2 stroke engine, not 4 stroke.
Over revving a cold saw especially without a bar and chain installed can cause a "cold seizure"as the piston will expand faster at the exhaust port.Always allow the saw to warm up first.
Hey good job on finding the problem! Carb, ignition, and plugged fire screen all yield the same issues with these engines. I'm a mechanic on saws as well and carb or plugged fire screens are the most common problem. And the plugged fire screen is normally caused from the customer not running the saw full throttle, or like you mentioned running to much pre-mix. Have fun!
Gonna check my exhaust next. Rebuilt a Walbro carb on a $5 yardsale Mac 3200 today. Got it started (amd smiled) and seems to run real well (till ya try to start cutting wood). Bogs bad. Step 2... Learn proper jet settings. Step 3... Maybe go back and adjust the needle valve lever thingy properly. I think it may be a little off still. Walbro 247 = .65 - .70. But first... exhaust. Finger crosses and the wood is ready.
This is fantastic advice! I have the same model chainsaw and after I cleaned the screen and the deflector, it ran like a charm. Thank you for this valuable knowledge.
Nice,got them work immediately. I have Stihl 170 and 290, both of them had no power and hard to keep them running idle. I opened the front screens , both of them clogged. I did not have new screens and they are hard to clean, so I just got rid of them, when I get new, I put them on.
It's a "spark arrestor". I cut logs for 22 years and they tend to clog up on you. It was something that you can do without. The reason we had it was because the worker's insurance demanded we have it . They would check it randomly . But if you take care not to cut wood with the muffler too close , you can just take it off. It is meant to prevent sparks from the muffler to which to this day I have never seen happen.
I thought the spark arrestor was to prevent forest fires, not to appeal to some arbitrary insurance issue. There's a reason the insurer wants it there, for liability. Just because one person never started a forest fire, doesn't mean it can't happen.
Good information.... also remember to check the fuel line in the gas tank. If regular gas is used, then it might have ethanol and that breaks down the rubber in the gas line over time.(94 contains no ethanol.)Then at high demand, full throttle, the line can collapse inside the tank and the saw bogs. Easy fix by simply replacing the line with new one. (I had to wait to have my new gas line delivered so in the meantime I used a steel spring from a pen as a stent in the line and it worked perfectly.) Stihl is a great little saw.
Great advice. My Stihl MS193T chainsaw would run great at idle, but bog down when trying to rev. I cleaned the screen on the exhaust and the problem is fixed! Thank You!
My Stihl MS 290 started bogging down when giving it gas & with no load (not cutting). I tried all the basic stuff,.. fuel, carb setting, air filter, spark plug,... nothing. I pulled the muffler filter and it was basically 100% clogged. I cleaned with carb cleaner and a wire brush, put it back in.... & the saw runs like it was new. I would have never thought of this simple fix if I did not watch this video. Thanks!
Great video - Thanks for your help. I have a Makita DCS520 that kept bogging. Was skeptical at first as I am in New Zealand and didn't think I would have the screen. Sure enough it was clogged up. Pulled it out fired it up and ran like a dream. Very thankful for everyone taking the time to post videos like yours to help others.
Thank you for the info. I’m having an issue with a new saw. Starts fine. Used it for 30 minutes, shut it off to refuel, restarted fine. But now it won’t take any throttle at all. I’m assuming it is a carb adjustment issue and I’ll have to either attempt adjusting the saw, or take it back to the seller for adjustment?
Your tips headed me in the right direction for a bad bog problem. Had some gas in the saw that was ??? despite having a date on it with stabil fuel additive in it. Replaced the fuel with fresh fuel and it eliminated the bog completely.
Wow! Wide open throttle on the initial start???? Obviously you forgot that it's air-cooled and the only lubrication for that tny piston comes from the fuel mix. Brilliant!
Thank you !!!! This video did the trick for my Husqvarna 51L. Took off the muffler, cleaned it and the screen and it runs like a champ! Thank you again!
Great Video. Since its Spring, I went to check on my chainsaws. 2 out of 3 are having trouble staying running. Fresh gas and oil mix. Fresh spark plugs. Now, thanks to this video, I'll be looking at that mesh screen. And periodically clean it after x amount of uses.
Great tip! I was ready to junk mine over this little issue. Went over everything and couldn't find the problem until I watched this video. Thanks for the help! Runs great again.
Thank you very much! Was cutting with my husky and it didn't want to cut it was bogging. Did everything even considered buying tool to adjust L and H settings. Then I found your video and first thing I did was took this wire mesh off and cleaned it. Now its going like a beast and no problems.. Very helpful! Thank you. You get a like from me :)
Thank you... Just went through the carb, New cleaner, spark plug.. Still holding an idle, but bogging and both low/high adjustments doing nothing. Never would've thought to check the exhaust, she's happy now.
Not to be critical but u should let it warm up a bit b4 u run it wide open like that. Give that piston bore a chance to expand a bit. Outher than that thanks for the vid.
contacted stihl about the arrestor screen for a Stihl 171 and had a reply back The MS 171 supplied in the UK does not have an arrester screen as they were only available in the product version MS171-Z which were supplied in Australia, USA and Canada.
Great video on the importance of checking the spark arrestor screen. An often overlooked piece on a chainsaw by many. It was nails on a chalkboard for me to hear you peg and even briefly hold that throttle just after starting. If this becomes a users habit it will lead to cold seizure scoring of your piston & cylinder. Newbies & construction guys (infrequent users that just wanna get to cutting once started) are notorious for cold seize scoring a chainsaw. Let your chainsaw warm up before pegging that throttle, ladies & gentlemen. It will keep its power we & last much longer if you do. That holds true for any motorized device including your vehicle.
I run a bunch of Stihl power tools daily in a commercial setting. We always take the spark arresters out. The eventually clog up irrespective of a correct mix or not. We absolutely mix the correct ratio. My guess is, they only put those on for liability reasons. Maybe so Stihl dealers can make minimum 30min- one-hour labour charges and diagnosis fees for a two minute job, for something very obvious to those who know.
Just typed in stihl chainsaw loosing power and this came up. Funny enough I have the exact same saw. Watched the video and that was my problem. 10 min later I'm up and running again so thank you.
My ms170 was bogging down. I was afraid it was a carb or compression problem. Searched the TH-cam and watched this video to diagnose. Turns out the spark arrester was filthy. I didnt even know chainsaws had spark arrestors until I watched this video. Cleaned it and it runs like a top now. Thanks!
I had similar problem with my leaf blower (also a Stihl in my case). It started but ran roughly and had low power. Such an easy thing to check and fix - it simply unscrews. Cleaned by soaking in gas and gentle fine wire brush. Now a part of my annual clean/maintenance.
I needed this video about 4 years ago.. lol.. I bought a Remington back in 2013 used it for wood cutting, then skipped a year, using just my electric heat.. 2015, I got the Remington out and it wouldn't start very well, finally got it to start then by holding the choke open a little it would idle but if I tried to throttle it. It would die. I just went out and bought a Kobalt 80volt electric. No more gas/oil mix or yanking on ropes.. Anyway good video.. BTW, I sold that other saw for $1.. The guy later said that he couldn't get it to run either.. If I see him, I'll pass this info on to him to check this.. or I might try to buy it back for 50 cents.. lol (he was my cousin or it wouldn't have been $1)
You are the man! I have an almost new Stihl MS171 and it totally bogged out on me today just about half way through an atv trailer load of wood. I had to leave and come home because the saw just would not power through a cut but would idle all day if left alone. I have only burned 5 L of fuel in it so far and it's mixed 50:1 with Stihl oil that the dealer sold me with the saw to get the 2 year warranty. That's two 100ml bottles in a 10L can of gas. It was on its way to the dealer tomorrow until I watched your video. Thanks a bunch! Is there a better oil? That screen plugged up quickly.
Scott F. Stihl oil is pretty good.. Double check mix ratio.. If it continues to clog up and After the warranty is up.. Pull the screen out and run without it.
@@Foxboss9It's pretty bad about leaving carbon behind though. I also have a 171 with bogging issues, but it's only when the saw has been sitting for a few minutes or with a cold start. It seems like it doesn't want to properly draw fuel at first. On one hand, it helps avoid a cold seizure. On the other, I still have to slowly introduce the throttle after the saw has been sitting.
If you only use chainsaw once in a while; only use ready mix gas and oil sold at Canadian Tire or at your local chainsaw dealer. It has high octane and has a shelf life of 2 years, no more problems with your chainsaw gumming up after that.
In Ontario Canada, Premium fuel at Shell Stations does not contain Ethanol. Best choice for 2 strokes and show cars that are not used in Winter. Excellent video.
Great tip! I always go a tad heavier on oil. Only because very seldom does the saw idle more than 45 seconds. Other than warm up. It. Its wide open. I'm not a climber. Can understand that. From what I understand they have leaned everything out too. For epa junk. Spark arrestors a good idea. Never a fan of Sthil . Started with Mchulloch only because only descent service guy. 1010,610, and 710. All by age 16. East coast. Prefer Husky or jonsered. Lighter faster. Got a husky 40 brothers I bought my dad decades ago. Dad and one brother gone. Saw still here. 372xp. Saw does the work. Have to be on your toes. .what's your choice and why?
You did an excellent trouble shoot from A to Z or really from A to X. You still have to put the bar and chain on and cut a moderate sized piece of wood to be certain of high speed mixture. I bought a barely used bigger brother to that saw, the ms250, and it's a beautiful thing to run.
+Foxboss9 I have to ask you what gunked up that arrester screen like that? I run echo 2 stroke oil by the gallon and I really never clean a screen at all. heck it looked like someone was old school running a 16 to one mixture?
+Burt Hulbert could be.. Even ISO LEG-D stuff like Echo oil will clog up if it sits in the tank for a year to a year and a half.. The gas may evaporate but the oil remains.. Just Normal customer abuse..
@@burtvhulberthyhbn7583It shouldn't gunk up if it's regularly run at full throttle. If it spends a lot of time idling or just sits with gas in the tank, then you'll start having issues.
Hi Foxboss9, I just replaced the rotted off clunk/fuel line. Thought that would make her run. Nope, runs, but the top end dies out. I run 32:1 gas/oil mix, so your idea of the exhaust screen may be the problem, I will try that next. Gas is two weeks old. I run 2 stroke "Chain saw engines" on my large radio control warbird aircraft, so have a fair amount of experience with these engines. I have run 32:1 to great success, for over 5 years. So, this poulan engine ran great 2 months ago. A couple of weeks ago, I tried it, and blah, hardly ran. Could be a combination of errors such as dirty fuel screen in the carb. Engine is 7 years old and has run great up till now.
lbjlbj1 all stihl products run 50:1 period, youll end up frying the piston and cylinder and it will not take long. first sign is your gonna start loosing compression
curtis kitchens that is what Stihl recommends using their oil... Better mix oil such as Echo's ISO-LEG-D rated oil can be used at a lesser ratio. These guys aren't worried about warranties on their old saws. MFG recommendations are just that. For every saw that has burned up there are 20 doing fine. Just like no load full Rev.. Fuel limitation based on carb design will not allow a well tuned engine to scatter if it's wound up to it's upper limits.. For every one that has come apart there are 70 that don't experience I'll effects. Theoretical operation standards are rarely the actual abilities. I listened to all the Mfg's during all my training over the years and found that they all are teaching what is in the best for the MFG and never, ever what you can get away with. With the exception of Echo's advanced failure analysis class in which they have shown that you can run their cheapest string trimmer on straight gas, at full throttle for over an hour (refill on the fly) and will continue to run. It will be damaged but can be done. Showing that with a very minor amount or oil in the mix it will do the same thing without damage. But obviously they don't recommend it.
Great video. Have the same saw it bogs down when I full throttle sometimes. If you do another it would be nice to see and hear how it fails before fixing.
Foxboss9 is right about fuel. Not only should it be keept fresh, but at the right ratio. I had problems with my 42cc Poulan saw bogging after running wide open for 20-30 sec. I fashioned a tool to adjust the carb (I'm pretty expert at tuning). It ran much stronger, but still bogged after running wide open for 20-30 sec. I made a batch of fresh fuel at 35:1, though the engine calls for 40:1. That did the trick. It now smokes a bit (no smoke is not healthy), runs super strong, and never bogs. Man, that saw cuts like it's angry now. When you have 3 or 4 2 stroke tools calling for 30:1 through 50:1, you have to be careful. Label your fuel cans!
I have a decent 044 and it started bogging down after cutting a few cords of wood. Took it into a local saw shop. He said he was going to. Retune the carb real fast. He used an allen wrench. First off its a flat head screw on the carb. He said i needed a new carb. Would cost me $100. Went home and retuned the carb right. Runs great.
I was also having the issue of short idle and no rev. My saw has less than 2 hours of use. I checked everything like has been mentioned on several youtube videos and forums and all was fine, as it should be. It appears the in tank fuel filter keeps the tube off the bottom of the tank too high. I still had, what I thought was, plenty of fuel (about 1/4 to 1/3 full) but was having the run issues. I topped the tank back off and after it idled long enough to purge any air, it ran as it should. Hopes this helps.
I had another cause of bogging out that I’ve fixed. I accidently used chain oil in the fuel instead of T2 engine oil. The engine run at idle but bogged out at high revs. When I put the right fuel in it was OK. I went through all of the cleaning and adjusting processes it was only when I tried a new mix of fuel that I realised the fuel in the tank was yellow, the only T2 oil that I have is pink but both bottles are black and look the same. All the best . . . Andy
I hope you see this.....Trying to fix a friends Stihl mini boss. Starts fine but there is a "sweet spot" in the trigger that allows it to go to full speed and it seems to be halfway of the trigger pull, if you pull trigger all the way, its slows and runs rough. I feel it is a throttle linkage, what do you think? Its looks like relatively new saw, he has always used Stihl fuel mix. Starts with no problem. Thanks............Brock
Stihl MS170 and 180's are notorious for this problem. The carbs are non-adjustable and often run a little too rich. This results in blocking of the spark arrestor with the oil in the exhaust. I remove my arrestor and only reinstall it for summer use, when fire is a worry.
I've been searching for hours to learn something simple: How to set the timing on a two stroke engine. It is a Weedeater 698 with a Kioritz K-3W engine. I pulled the plug so I could see the piston reach TDC then backed off a bit a bit then adjusted the points until they opened. What I don't know is how exactly how much a bit should be. It seems to work OK but is slow to get up to speed. I want to learn a more accurate way of setting the timing. Thanks.
Posting this around because I couldn't find anybody else online talking about it: After having a world of trouble with my Stihl MS-250 not starting, I decided to check the coil. It had spark, but I guess it wasn't strong enough to fire the plug. Forums have people that tell you to replace the coil in a case such as this, but a few say the coil seldom goes bad in a Stihl. My saw is not that old. Even so, I decided to pull the coil and replace it with one out of another older ms-250 I have. Then I noticed the gap between the old saw's coil and flywheel. It was not the same as the one on the problem saw. The non-starting unit had a wider gap. I got back online and found the correct gap setting should be 25 thousandth (can use a business card to set the gap). I decided to only remove the coil and clean it up, then reset the gap. I put everything back together and used a business card to set the gap. Then pulled the spark plug and made sure it was gaped at 25 thousandths too. The saw fired up and runs like new! It's hard to understand how that gap changed. It was never torn down till now, and it used to run very well for the longest time. Maybe buildup from the dust and oil lodged between the two components and caused it? But the torque screws holding it in place were very tight, and I can't see any reason for the coil to have slipped. But now happy... got my toy to working again.
mine would start cold no problem but if it would if it ran for a minute it wouldn't start for a couple hours was the coil. how does Chinese one minute so I spent nine bucks & stuck another one in it again
good video but these saws have very poor carbs on them i remove them and put a fully adjustable carb on and the saw runs so much better more power and no bog but after installing the new carb you need to set the rpms on it to factory settings the old junk carb you just throw it away. the new carb is a Stihl carb costs $28 and it fits the 025 saw but will fit the 170-180 I have done hundreds of these swaps it turns the saw into a real saw
Stihl dealer is where you get the carb the part number is 1123-120-0605 and there is a couple things you need to do to it but its very easy first the pulse hole in this carb has 2 holes one is plugged you need to remove the small brass plug best way drill it then use a pick to pick it out next you will need to slot the butterfly rod out i use a cut off tool takes 10 seconds and your done the new carb just has a hole in it grind the slot in for the throttle rod then install carb just like the old one then you will need to put a litte rtv in the filter housing where the little round vent on the old carb went into air cleaner then put it together there are jet adjustment holes in air cleaner box already then you will need to drill a new hole in the handle for idle speed screw i just eye ball it then you will need to put a small slot in the housing so you can adjust the jets when the top cover is on very simple use a drill or cut off wheel then your done fire it up set the high and low speed jets now take it out and cut with it way more power and no more bogging down its very easy it takes me 5 min to do the whole job
Why I like buying the premix out of the can good for 2 years. How often does a home owner cut wood . Shut off leave it until who knows when . 20.00 Gal it is worth it . Keeps it nice clean. I just picked up 2 Echo CS340 and 440 at a recycle center just need to clean carb out.
the spark arrestor screen can clog from user error as well, not always too rich. users at work have been able to clog screens, usually only after 2-3 seasons. the fuel they run is ethanol free, stihl ultra 50:1. once you run an engine with plugged screen you never forget the characteristics. probably not the best idea to free rev that cold engine at initial start up.
your video on the stihl chainsaw "replacing the studs" was very informative. Do you have a video of replacing the chainbar tightening stud on a stihl ms251? It's the small stud that moves the chainbar forward to tighten and backwards to loosen.
I guess I just fixed mine by removing the muffler and cleaning the screen. I had tried the low/high speed adjustment and only when I did this did it start to work. Thanks.
@Foxboss9 thankyou very much ! You just saved me a lot of money and 2 days sending my chainsaw to a service company. I guess you do learn something new everyday! Thankyou again.
I'm having the bogging problem, and then it stalls. Checked the spark arrester and it's fine. Took most of the parts out of the carb - seem to be okay. I bought this MS 310 in 2004 after Hurricane Charley, and it did a great job, used it for a few more jobs and it did fine. One day, a few years ago, it started doing this. Now I'm recovering from Hurricane Matthew, and I need it to work. There is a huge oak tree out front being held up by a 10,000lbs strap. I have a little Poulan, which might be good to go after the small branches, and that can fix the immediate problems. The Poulan had bad fuel lines from running ethanol - replaced those and it works fine. I ran this Stihl for about ten minutes before it started doing this, a repeat of what it did several years ago. I drained the fuel and put in new. Spark plug looks good. ???
There is a small screen inside the carburetor that may be clogged.. A complete cleaning of the carb or rebuild may be needed.. Just to get it going I would try to spray carb cleaner through all the passages it may clear it up.. Of course check the fuel filter at the bottom of of the tank on the fuel line.. And the duck bill air intake on the fuel cap too..
Everything on this machine looks to be in nearly perfect condition. One guy I talked to at his repair shop suggested that the diaphragm might be too stiff and needs replacing. I ordered a new diaphragm and the screen on the bottom, which looks like a screen, buy really appears to be a reinforced rubber valve sheet (they called it "the pump" and they called the upper diaphragm something else, but I think the upper diaphragm is really the fuel pump). It's a 12-year-old machine, so replacing these two pieces for $10 seems an obvious step. The fuel filter, from the outside, looks to be in immaculate condition. Having the carb completely apart, I can't tell what is to be cleaned with carb cleaner. It's spotless, inside and out. I'll let you know how it turns out, Friday, when the parts come in. Thanks for your informative video - it was helpful. Next week, if this comes out okay, I'll post a video on taking down a huge Laurel Oak tree.
Robert Mertens something I learned a long time ago working on small engines because everything is so tiny, don't assume a passage is open because it looks like it is. Make sure that you can run a small wire through all the passages. The other thing that happens whenever residue of fuel is left inside of a small engine, is that the Rings could get gummed up and stuck in the ringland and not being pressed fully against the cylinder walls. Good luck!
I noticed the carb needs a little adjustment. Mine was running the same way. While engine running, I would take low idle and turn in a 1/4 turn, if run worse, I would now run it out get back the 1/4, and add another 1/4 turn, if this didnt change, then I went to high screw and used the same principle. Now mine is running fine. I did this on both of my saws Stihl 021, and ms250. One more note. I poured the gas out and started with fresh. When I got done running saw, I poured my gas back into my gas can using funnel. I started my chainsaws and ran every drop out of fuel line and remainder of carb. Now it should be good to store till next use. I dont have to worry about diaphragm, etc
Very true! However, one thing you could try would be to remove the spark arrestor for testing purposes only. Your test period may be 5 minutes, or may be an indefinite test period. Some places (national forest, etc.) will require them (and check for them.) Not just on a chainsaw, but a dirtbike, etc. etc. etc.
Depends on saw, exhaust screen, spark plug, good clean fuel, air filter clean, been sitting carb cleaning, inspection. Runs bit funky carb possibly, then adjusting like here...
Great list of things to check. What I would like to see is how to test each of those things. Checking the air filter is easy to do visually. But how do I know whether it's the spark? Is there an easy way to test that? How do I know if it's the carb? Can I inject some gas in the air intake and see if it starts but then dies? Would that indicate the carb?
When I'm done using my saw and I'm not going to use it for a while I always pour out the fuel and run it til it runs out of gas that way when I get ready to use it next time I can put in fresh fuel. Saves a lot of headaches later.
When I was a teen my dad had a monster Lombard Comango which we would cut cords and cords of wood every year in Maine with, he never ever got a chance to show me how to tune it, just sharpen it!
Over time that screen (spark arrestor) can rust apart and pieces could find their way into the cylinder. I blew a saw that way a few years ago. Chuck it. Thumbs up for the vid.
Fantastic insights and a great video, Now my interpretation: gGet rid of the screen, put it in the garbage and reassemble and never worry about that again.
Thank you so much for sharing this. I’ve pretty much done everything EXCEPT check the exhaust. I bet anything that’s the problem. Only been an operator for two years so I’m still wet behind the ears when it comes to this tormenting wretch. But I’m going out there now and fix it... thanks to YOUR HELP. Stay warm!!! I know I can now!!!
I was having low power from my saw as I tried to figure out what was wrong. My saw is the same model as this one. I spent the day cleaning the carburetor and not cutting wood. I saw your video and checked the screen on the exhaust and found it to be plugged just like the one you showed in video. At first soap and water, that didn't work, tried alcohol, didn't work. I used Lucus injector cleaner, it worked well. Thanks for sharing the tip, it saved downtime and didn't need to take it in for repair at shop.
Cole B yu spent the day cleaning a carb.. don't quit yur day job
Next time try to use carb cleaner and it should be OK
How to start a chain saw?
"big ass puss" People like you dont quit their day Or night jobs.. They get fired!
next time it clogs up chuck it in the trash that’s where they belong.
Of all the videos I have watched on chainsaw tuneups not a single one of them has mentioned this filter on the exhaust. Thank you for getting this information out there.
Instant results on my Stihl MS 180! I had changed the fuel filter, air filter, mixed fresh fuel, installed a new spark plug and then stripped and cleaned the carb but to no avail. Checked the spark arrestor screen after watching your video and found it to be plugged solid, just as in your video. Cleaned up the screen with some carb cleaner and now the saw runs like a charm. Certainly appreciate you sharing this tip for trouble shooting. Cheers.
Great advice on something I never thought to check. I have a similar model mine is the MS 250 and it is starting to bog a little occasionally so I'm going to check to see if mine has this screen as well. Thank you
My MS170 was only two years old and started bogging down at higher speed settings. Didn't think your fix would apply to such a new saw but it was the solution! Thanks for the great video!
Straight to the point! Well done, no music you didn't introduce us to your dog or your kids, though I am sure they are great but I just wanted to know how to tune my saw up and that's exactly what I got.
Thank you ! I'm a handyman guy and occasionally I've done some backyard mechanic stuff for over a half century. I've worked on all kinds of motors, but never had I come across a motor that uses some little screen over the exhaust. I had looked all over the internet to try to figure out why my small chainsaw was bogging down. Who would think there would be a little screen completely clogged with carbon. I cleaned it off and it's running great now, especially because I put a new spark plug in it. It's just a little Stihl ms150c that I use for cutting branches. Using my larger Stihl for that wears me out. Thanks again.
It’s also good to keep in mind never to run the saw too long or at all without that bar and chain on and tensioned properly. Not only could you over heat and over rev the engine but it can cause very expensive irreparable damage in the long run. Cheers!!
Speaking of the bar - flip the bar over everytime the chain gets removed. Helps keep the wearing of it distributed to both sides. When re-attaching the bar, put a slight upward pressure on the bottom of the tip of the bar while tightening the it.
What ‘very expensive irreparable damage’ would it cause? Why do you think the engine would overheat? You also can’t over rev the engine, short of just holding it wide open for a long time. Chainsaws are designed to rev, and newer ones all have limiters in the ignition. It’s a 2 stroke engine, not 4 stroke.
Over revving a cold saw especially without a bar and chain installed can cause a "cold seizure"as the piston will expand faster at the exhaust port.Always allow the saw to warm up first.
Thank You!! My 15 year old son watched your video, and now the chain saw is working great!
That is great!
+Paul L: A 15 year old boy is too young to be handling a chain-saw.
All depends on how he grew up...IMO
Lol did you grow up in a bubble? Or just i Citydiot @@johnd942
Hey good job on finding the problem! Carb, ignition, and plugged fire screen all yield the same issues with these engines. I'm a mechanic on saws as well and carb or plugged fire screens are the most common problem. And the plugged fire screen is normally caused from the customer not running the saw full throttle, or like you mentioned running to much pre-mix. Have fun!
Military Chevy or running CHEAP MIX OIL. run full synthetic it wont plug up
Gonna check my exhaust next. Rebuilt a Walbro carb on a $5 yardsale Mac 3200 today. Got it started (amd smiled) and seems to run real well (till ya try to start cutting wood). Bogs bad.
Step 2... Learn proper jet settings.
Step 3... Maybe go back and adjust the needle valve lever thingy properly. I think it may be a little off still. Walbro 247 = .65 - .70.
But first... exhaust.
Finger crosses and the wood is ready.
The mesh screen is a "Spark Arrest" preventing sparks from flying out the exhaust in a dry environment ;)
This is fantastic advice! I have the same model chainsaw and after I cleaned the screen and the deflector, it ran like a charm. Thank you for this valuable knowledge.
I had crap old fuel. As an amateur I never had realised this could have such a profound effect. New fuel, works a dream, thank you!
Well explained Basic Maintenance Thank you for sharing The mesh is a spark arrestor for use in high risk Fire areas Dry forestry, Sawmills Etc
Nice,got them work immediately. I have Stihl 170 and 290, both of them had no power and hard to keep them running idle. I opened the front screens , both of them clogged. I did not have new screens and they are hard to clean, so I just got rid of them, when I get new, I put them on.
It's a "spark arrestor". I cut logs for 22 years and they tend to clog up on you. It was something that you can do without. The reason we had it was because the worker's insurance demanded we have it . They would check it randomly . But if you take care not to cut wood with the muffler too close , you can just take it off. It is meant to prevent sparks from the muffler to which to this day I have never seen happen.
Antonio Arellano run full synthetic mix oil it wont plug up. run the cheap stuff it will plug up because it has crude oil in it
i would think if it was throwing sparks it would be a good sigh of the saws engine starting to die.
The sparks are carbon, not metal.
Good info! Thanks for your input. Experience will always win.
I thought the spark arrestor was to prevent forest fires, not to appeal to some arbitrary insurance issue. There's a reason the insurer wants it there, for liability. Just because one person never started a forest fire, doesn't mean it can't happen.
Thanks for getting and keeping it to the point without wasting time showing me where the dog sleeps.
Good information.... also remember to check the fuel line in the gas tank. If regular gas is used, then it might have ethanol and that breaks down the rubber in the gas line over time.(94 contains no ethanol.)Then at high demand, full throttle, the line can collapse inside the tank and the saw bogs. Easy fix by simply replacing the line with new one. (I had to wait to have my new gas line delivered so in the meantime I used a steel spring from a pen as a stent in the line and it worked perfectly.) Stihl is a great little saw.
Thanks..good points for sure..
If you're spark arrestor is clogged like that, your mix is too oily, and exhaust port needs cleaning 🧐
Great advice. My Stihl MS193T chainsaw would run great at idle, but bog down when trying to rev. I cleaned the screen on the exhaust and the problem is fixed! Thank You!
My Stihl MS 290 started bogging down when giving it gas & with no load (not cutting). I tried all the basic stuff,.. fuel, carb setting, air filter, spark plug,... nothing. I pulled the muffler filter and it was basically 100% clogged. I cleaned with carb cleaner and a wire brush, put it back in.... & the saw runs like it was new. I would have never thought of this simple fix if I did not watch this video. Thanks!
Brother you saved me $45 and taught me a new skill. Thank you 10 time over.
Great video - Thanks for your help. I have a Makita DCS520 that kept bogging. Was skeptical at first as I am in New Zealand and didn't think I would have the screen. Sure enough it was clogged up. Pulled it out fired it up and ran like a dream. Very thankful for everyone taking the time to post videos like yours to help others.
Thank you for the info. I’m having an issue with a new saw. Starts fine. Used it for 30 minutes, shut it off to refuel, restarted fine. But now it won’t take any throttle at all. I’m assuming it is a carb adjustment issue and I’ll have to either attempt adjusting the saw, or take it back to the seller for adjustment?
Your tips headed me in the right direction for a bad bog problem. Had some gas in the saw that was ??? despite having a date on it with stabil fuel additive in it. Replaced the fuel with fresh fuel and it eliminated the bog completely.
Dave V Great! 😊👍
Wow! Wide open throttle on the initial start???? Obviously you forgot that it's air-cooled and the only lubrication for that tny piston comes from the fuel mix. Brilliant!
Nice job. Had same issue. Chased other issues for hours before finding this cause. Thanks for sharing. Well done.
Thank you !!!! This video did the trick for my Husqvarna 51L. Took off the muffler, cleaned it and the screen and it runs like a champ! Thank you again!
Thanks heaps, great video, straight to the point! Clogged screen is now clean and MS170 is going great again.
Great Video. Since its Spring, I went to check on my chainsaws. 2 out of 3 are having trouble staying running. Fresh gas and oil mix. Fresh spark plugs. Now, thanks to this video, I'll be looking at that mesh screen. And periodically clean it after x amount of uses.
✅😁
My teenage years of cleaning my pipe and bong screens have prepared me for this exact task.
+Robert King And there it is..Best comment!!
Robert King LMFAO
So, how much does it help ?
Robert King hahahahaaa!!! IK-R?
like a boss
Great tip! I was ready to junk mine over this little issue. Went over everything and couldn't find the problem until I watched this video. Thanks for the help! Runs great again.
I love it when the first easiest thing to check is all that is wrong. Just checked mine and it was clogged bad, thanks for the video!!
Thank you very much! Was cutting with my husky and it didn't want to cut it was bogging. Did everything even considered buying tool to adjust L and H settings. Then I found your video and first thing I did was took this wire mesh off and cleaned it. Now its going like a beast and no problems.. Very helpful! Thank you. You get a like from me :)
Cool!
Thank you... Just went through the carb, New cleaner, spark plug.. Still holding an idle, but bogging and both low/high adjustments doing nothing. Never would've thought to check the exhaust, she's happy now.
tampabayrider Great News 👍
You're a star, mate! Thanks. Exhaust was the problem. Shared knowledge is what makes the world go round. Thanks again.
great news! thanks for watching😀
You should have run the saw with the bogging problem to show what it sounds like with the screen plugged.
Listen to the song "Lumberjack ". Forget who sings it....Jackle ?
@@anthonythorp7291 I havent jacked my lumber babaayyyy, since my chain saw youuuuuuuuuuuuu. lol yes Jackal.
Not to be critical but u should let it warm up a bit b4 u run it wide open like that.
Give that piston bore a chance to expand a bit.
Outher than that thanks for the vid.
contacted stihl about the arrestor screen for a Stihl 171 and had a reply back The MS 171 supplied in the UK does not have an arrester screen as they were only available in the product version MS171-Z which were supplied in Australia, USA and Canada.
Great video on the importance of checking the spark arrestor screen. An often overlooked piece on a chainsaw by many. It was nails on a chalkboard for me to hear you peg and even briefly hold that throttle just after starting. If this becomes a users habit it will lead to cold seizure scoring of your piston & cylinder. Newbies & construction guys (infrequent users that just wanna get to cutting once started) are notorious for cold seize scoring a chainsaw. Let your chainsaw warm up before pegging that throttle, ladies & gentlemen. It will keep its power we & last much longer if you do. That holds true for any motorized device including your vehicle.
He did that to a customer's saw.
Unbelievable.
You have to at least do a throttle squeeze on Stihl if it is on the half-choke.
And always full throttle immediately! Especially when it's super cold out !!!
You must be a chainsaw salesman..i was waiting for the saw to cold seizure..always let the saw warm up, before beating on it..lol
sarcasm... tee hee.
Great way of seizing up the piston in the saw !!
A great video have run saws for 40 years with Hydro and personal business. Thank you.
I run a bunch of Stihl power tools daily in a commercial setting. We always take the spark arresters out. The eventually clog up irrespective of a correct mix or not. We absolutely mix the correct ratio. My guess is, they only put those on for liability reasons. Maybe so Stihl dealers can make minimum 30min- one-hour labour charges and diagnosis fees for a two minute job, for something very obvious to those who know.
This is the best and most informative video I've seen in some time! Excellent work!
Just typed in stihl chainsaw loosing power and this came up. Funny enough I have the exact same saw. Watched the video and that was my problem. 10 min later I'm up and running again so thank you.
+cartelli50 great news!
My ms170 was bogging down. I was afraid it was a carb or compression problem. Searched the TH-cam and watched this video to diagnose. Turns out the spark arrester was filthy. I didnt even know chainsaws had spark arrestors until I watched this video. Cleaned it and it runs like a top now. Thanks!
Otto 81494 Great! Glad it helped out!
I had similar problem with my leaf blower (also a Stihl in my case). It started but ran roughly and had low power. Such an easy thing to check and fix - it simply unscrews. Cleaned by soaking in gas and gentle fine wire brush. Now a part of my annual clean/maintenance.
;-)
Thanks for the video. I just inherited my dads chainsaw and now I know a lot more about it.
Arian Smith 😊
I needed this video about 4 years ago.. lol.. I bought a Remington back in 2013 used it for wood cutting, then skipped a year, using just my electric heat.. 2015, I got the Remington out and it wouldn't start very well, finally got it to start then by holding the choke open a little it would idle but if I tried to throttle it. It would die. I just went out and bought a Kobalt 80volt electric. No more gas/oil mix or yanking on ropes.. Anyway good video.. BTW, I sold that other saw for $1.. The guy later said that he couldn't get it to run either.. If I see him, I'll pass this info on to him to check this.. or I might try to buy it back for 50 cents.. lol (he was my cousin or it wouldn't have been $1)
That was so helpful. Thank you. My local saw repair shop was going to charge me £70 UK. For what took me 20 minutes. Regards M
Thanks for the concise video. I fixed my saw in minutes!
You are the man! I have an almost new Stihl MS171 and it totally bogged out on me today just about half way through an atv trailer load of wood. I had to leave and come home because the saw just would not power through a cut but would idle all day if left alone. I have only burned 5 L of fuel in it so far and it's mixed 50:1 with Stihl oil that the dealer sold me with the saw to get the 2 year warranty. That's two 100ml bottles in a 10L can of gas. It was on its way to the dealer tomorrow until I watched your video. Thanks a bunch! Is there a better oil? That screen plugged up quickly.
Scott F. Stihl oil is pretty good.. Double check mix ratio.. If it continues to clog up and After the warranty is up.. Pull the screen out and run without it.
@@Foxboss9It's pretty bad about leaving carbon behind though. I also have a 171 with bogging issues, but it's only when the saw has been sitting for a few minutes or with a cold start. It seems like it doesn't want to properly draw fuel at first. On one hand, it helps avoid a cold seizure. On the other, I still have to slowly introduce the throttle after the saw has been sitting.
If you only use chainsaw once in a while; only use ready mix gas and oil sold at Canadian Tire or at your local chainsaw dealer. It has high octane and has a shelf life of 2 years, no more problems with your chainsaw gumming up after that.
+kodiak we don't have Canadian Tire in lower 48, especially in Alabama
davel8n I figured that much which is why I also mentioned your local chainsaw dealer ;)
kodiak could not agree more with you so many insist on 87 octane pump gas & don't understand that it's strictly an auto fuel
I use that canned fuel for all my 2 strokes. it's quite a bit more expensive but saves you a lot more money and time in the long run.
In Ontario Canada, Premium fuel at Shell Stations does not contain Ethanol. Best choice for 2 strokes and show cars that are not used in Winter. Excellent video.
Might also check the impulse line for cracks. Replace it if cracked or it won't idle/spool up right.
Great tip! I always go a tad heavier on oil. Only because very seldom does the saw idle more than 45 seconds. Other than warm up.
It. Its wide open. I'm not a climber. Can understand that.
From what I understand they have leaned everything out too. For epa junk.
Spark arrestors a good idea.
Never a fan of Sthil . Started with Mchulloch only because only descent service guy. 1010,610, and 710. All by age 16.
East coast. Prefer Husky or jonsered. Lighter faster.
Got a husky 40 brothers I bought my dad decades ago. Dad and one brother gone. Saw still here.
372xp. Saw does the work.
Have to be on your toes. .what's your choice and why?
You did an excellent trouble shoot from A to Z or really from A to X. You still have to put the bar and chain on and cut a moderate sized piece of wood to be certain of high speed mixture. I bought a barely used bigger brother to that saw, the ms250, and it's a beautiful thing to run.
👍😊
+Foxboss9 I have to ask you what gunked up that arrester screen like that? I run echo 2 stroke oil by the gallon and I really never clean a screen at all. heck it looked like someone was old school running a 16 to one mixture?
+Burt Hulbert could be.. Even ISO LEG-D stuff like Echo oil will clog up if it sits in the tank for a year to a year and a half.. The gas may evaporate but the oil remains.. Just Normal customer abuse..
@@burtvhulberthyhbn7583It shouldn't gunk up if it's regularly run at full throttle. If it spends a lot of time idling or just sits with gas in the tank, then you'll start having issues.
Hi Foxboss9, I just replaced the rotted off clunk/fuel line. Thought that would make her run. Nope, runs, but the top end dies out. I run 32:1 gas/oil mix, so your idea of the exhaust screen may be the problem, I will try that next. Gas is two weeks old.
I run 2 stroke "Chain saw engines" on my large radio control warbird aircraft, so have a fair amount of experience with these engines. I have run 32:1 to great success, for over 5 years. So, this poulan engine ran great 2 months ago. A couple of weeks ago, I tried it, and blah, hardly ran. Could be a combination of errors such as dirty fuel screen in the carb. Engine is 7 years old and has run great up till now.
Good luck
lbjlbj1 all stihl products run 50:1 period, youll end up frying the piston and cylinder and it will not take long. first sign is your gonna start loosing compression
curtis kitchens that is what Stihl recommends using their oil... Better mix oil such as Echo's ISO-LEG-D rated oil can be used at a lesser ratio. These guys aren't worried about warranties on their old saws. MFG recommendations are just that. For every saw that has burned up there are 20 doing fine. Just like no load full Rev.. Fuel limitation based on carb design will not allow a well tuned engine to scatter if it's wound up to it's upper limits.. For every one that has come apart there are 70 that don't experience I'll effects. Theoretical operation standards are rarely the actual abilities. I listened to all the Mfg's during all my training over the years and found that they all are teaching what is in the best for the MFG and never, ever what you can get away with. With the exception of Echo's advanced failure analysis class in which they have shown that you can run their cheapest string trimmer on straight gas, at full throttle for over an hour (refill on the fly) and will continue to run. It will be damaged but can be done. Showing that with a very minor amount or oil in the mix it will do the same thing without damage. But obviously they don't recommend it.
Amsoil synthetic two stroke oil at 100/1 mix ratio and high test fuel is your best way to go on these saws ! Never had a screen clog problem!
Great video. Have the same saw it bogs down when I full throttle sometimes. If you do another it would be nice to see and hear how it fails before fixing.
Foxboss9 is right about fuel. Not only should it be keept fresh, but at the right ratio.
I had problems with my 42cc Poulan saw bogging after running wide open for 20-30 sec. I fashioned a tool to adjust the carb (I'm pretty expert at tuning). It ran much stronger, but still bogged after running wide open for 20-30 sec. I made a batch of fresh fuel at 35:1, though the engine calls for 40:1. That did the trick. It now smokes a bit (no smoke is not healthy), runs super strong, and never bogs. Man, that saw cuts like it's angry now.
When you have 3 or 4 2 stroke tools calling for 30:1 through 50:1, you have to be careful. Label your fuel cans!
Great info... Dad always said it's the big three -air, fuel and spark ... Most fail to realize breathing = inhale AND exhale.
I have a decent 044 and it started bogging down after cutting a few cords of wood. Took it into a local saw shop. He said he was going to. Retune the carb real fast. He used an allen wrench. First off its a flat head screw on the carb. He said i needed a new carb. Would cost me $100. Went home and retuned the carb right. Runs great.
👍😁
Thanks for this information, quite helpful. One comment, though, the crud on the screen is really not corrosion.
I was also having the issue of short idle and no rev. My saw has less than 2 hours of use. I checked everything like has been mentioned on several youtube videos and forums and all was fine, as it should be. It appears the in tank fuel filter keeps the tube off the bottom of the tank too high. I still had, what I thought was, plenty of fuel (about 1/4 to 1/3 full) but was having the run issues. I topped the tank back off and after it idled long enough to purge any air, it ran as it should. Hopes this helps.
Thank you! I have spent way too many hours checking/cleaning the wrong spots!
jiminmontana 👍😁
I had another cause of bogging out that I’ve fixed. I accidently
used chain oil in the fuel instead of T2 engine oil. The engine run at idle but
bogged out at high revs. When I put the right fuel in it was OK. I went through
all of the cleaning and adjusting processes it was only when I tried a new mix
of fuel that I realised the fuel in the tank was yellow, the only T2 oil that I
have is pink but both bottles are black and look the same. All the best . . . Andy
I hope you see this.....Trying to fix a friends Stihl mini boss. Starts fine but there is a "sweet spot" in the trigger that allows it to go to full speed and it seems to be halfway of the trigger pull, if you pull trigger all the way, its slows and runs rough. I feel it is a throttle linkage, what do you think? Its looks like relatively new saw, he has always used Stihl fuel mix. Starts with no problem. Thanks............Brock
I like how within 2 seconds of starting it, you pegged the throttle and screamed her wide open. That's always good for a cold saw.
Old wives tale.. That's a 4 stroke issue
Stihl MS170 and 180's are notorious for this problem. The carbs are non-adjustable and often run a little too rich. This results in blocking of the spark arrestor with the oil in the exhaust. I remove my arrestor and only reinstall it for summer use, when fire is a worry.
That's a really organized workspace👌 definitly fits in a 5S program
Damm commies bringing in their organization techniques
I've been searching for hours to learn something simple: How to set the
timing on a two stroke engine. It is a Weedeater 698 with a Kioritz K-3W
engine. I pulled the plug so I could see the piston reach TDC then
backed off a bit a bit then adjusted the points until they opened. What I
don't know is how exactly how much a bit should be. It seems to work OK
but is slow to get up to speed.
I want to learn a more accurate way of setting the timing. Thanks.
Great video. Great info. Straight to the point and easy to follow. Great flow.
Posting this around because I couldn't find anybody else online talking
about it:
After having a world of trouble with my Stihl MS-250 not starting, I
decided to check the coil. It had spark, but I guess it wasn't strong
enough to fire the plug. Forums have people that tell you to replace the
coil in a case such as this, but a few say the coil seldom goes bad in a
Stihl.
My saw is not that old. Even so, I decided to pull the coil and replace
it with one out of another older ms-250 I have. Then I noticed the gap
between the old saw's coil and flywheel. It was not the same as the one
on the problem saw. The non-starting unit had a wider gap.
I got back online and found the correct gap setting should be 25
thousandth (can use a business card to set the gap). I decided to only
remove the coil and clean it up, then reset the gap.
I put everything back together and used a business card to set the gap.
Then pulled the spark plug and made sure it was gaped at 25 thousandths
too.
The saw fired up and runs like new!
It's hard to understand how that gap changed. It was never torn down
till now, and it used to run very well for the longest time. Maybe
buildup from the dust and oil lodged between the two components and
caused it? But the torque screws holding it in place were very tight,
and I can't see any reason for the coil to have slipped.
But now happy... got my toy to working again.
mine would start cold no problem but if it would if it ran for a minute it wouldn't start for a couple hours was the coil. how does Chinese one minute so I spent nine bucks & stuck another one in it again
good video but these saws have very poor carbs on them i remove them and put a fully adjustable carb on and the saw runs so much better more power and no bog but after installing the new carb you need to set the rpms on it to factory settings the old junk carb you just throw it away. the new carb is a Stihl carb costs $28 and it fits the 025 saw but will fit the 170-180 I have done hundreds of these swaps it turns the saw into a real saw
Stihl dealer is where you get the carb the part number is 1123-120-0605 and there is a couple things you need to do to it but its very easy first the pulse hole in this carb has 2 holes one is plugged you need to remove the small brass plug best way drill it then use a pick to pick it out next you will need to slot the butterfly rod out i use a cut off tool takes 10 seconds and your done the new carb just has a hole in it grind the slot in for the throttle rod then install carb just like the old one then you will need to put a litte rtv in the filter housing where the little round vent on the old carb went into air cleaner then put it together there are jet adjustment holes in air cleaner box already then you will need to drill a new hole in the handle for idle speed screw i just eye ball it then you will need to put a small slot in the housing so you can adjust the jets when the top cover is on very simple use a drill or cut off wheel then your done fire it up set the high and low speed jets now take it out and cut with it way more power and no more bogging down its very easy it takes me 5 min to do the whole job
+Sandy Wanous damn didnt they teach you in school to use a period at the end of a sentence?
+Sandy Wanous You should do a step by step video on that.. I think it's something that needs to be shown.. thanks for the comment!!
Sandy Wanous please send me the carb.number. in order to bye one for my stilh
You got some good tips and info...but I gotta say, your ability to construct sentences and use punctuation is more than archaic.
Why I like buying the premix out of the can good for 2 years. How often does a home owner cut wood . Shut off leave it until who knows when . 20.00 Gal it is worth it . Keeps it nice clean.
I just picked up 2 Echo CS340 and 440 at a recycle center just need to clean carb out.
great vid! thx! but what is your advice when the same model isnt cutting as strong?
Thankyou. Similar problem on strimmer. Didnt know there was a gauze on muffler. Sorted my liw power, it is like a new one now. 👍
brian riding 👍😁
the spark arrestor screen can clog from user error as well, not always too rich. users at work have been able to clog screens, usually only after 2-3 seasons. the fuel they run is ethanol free, stihl ultra 50:1. once you run an engine with plugged screen you never forget the characteristics. probably not the best idea to free rev that cold engine at initial start up.
your video on the stihl chainsaw "replacing the studs" was very informative. Do you have a video of replacing the chainbar tightening stud on a stihl ms251? It's the small stud that moves the chainbar forward to tighten and backwards to loosen.
Sorry I don't. This saw was for the most part in very good shape so no other fixes were needed.
I guess I just fixed mine by removing the muffler and cleaning the screen. I had tried the low/high speed adjustment and only when I did this did it start to work. Thanks.
@Foxboss9 thankyou very much ! You just saved me a lot of money and 2 days sending my chainsaw to a service company. I guess you do learn something new everyday! Thankyou again.
I'm having the bogging problem, and then it stalls. Checked the spark arrester and it's fine. Took most of the parts out of the carb - seem to be okay. I bought this MS 310 in 2004 after Hurricane Charley, and it did a great job, used it for a few more jobs and it did fine. One day, a few years ago, it started doing this. Now I'm recovering from Hurricane Matthew, and I need it to work. There is a huge oak tree out front being held up by a 10,000lbs strap. I have a little Poulan, which might be good to go after the small branches, and that can fix the immediate problems. The Poulan had bad fuel lines from running ethanol - replaced those and it works fine. I ran this Stihl for about ten minutes before it started doing this, a repeat of what it did several years ago. I drained the fuel and put in new. Spark plug looks good. ???
There is a small screen inside the carburetor that may be clogged.. A complete cleaning of the carb or rebuild may be needed.. Just to get it going I would try to spray carb cleaner through all the passages it may clear it up.. Of course check the fuel filter at the bottom of of the tank on the fuel line.. And the duck bill air intake on the fuel cap too..
Everything on this machine looks to be in nearly perfect condition. One guy I talked to at his repair shop suggested that the diaphragm might be too stiff and needs replacing. I ordered a new diaphragm and the screen on the bottom, which looks like a screen, buy really appears to be a reinforced rubber valve sheet (they called it "the pump" and they called the upper diaphragm something else, but I think the upper diaphragm is really the fuel pump). It's a 12-year-old machine, so replacing these two pieces for $10 seems an obvious step. The fuel filter, from the outside, looks to be in immaculate condition. Having the carb completely apart, I can't tell what is to be cleaned with carb cleaner. It's spotless, inside and out. I'll let you know how it turns out, Friday, when the parts come in. Thanks for your informative video - it was helpful. Next week, if this comes out okay, I'll post a video on taking down a huge Laurel Oak tree.
Robert Mertens something I learned a long time ago working on small engines because everything is so tiny, don't assume a passage is open because it looks like it is. Make sure that you can run a small wire through all the passages. The other thing that happens whenever residue of fuel is left inside of a small engine, is that the Rings could get gummed up and stuck in the ringland and not being pressed fully against the cylinder walls. Good luck!
I noticed the carb needs a little adjustment. Mine was running the same way. While engine running, I would take low idle and turn in a 1/4 turn, if run worse, I would now run it out get back the 1/4, and add another 1/4 turn, if this didnt change, then I went to high screw and used the same principle. Now mine is running fine. I did this on both of my saws Stihl 021, and ms250. One more note. I poured the gas out and started with fresh. When I got done running saw, I poured my gas back into my gas can using funnel. I started my chainsaws and ran every drop out of fuel line and remainder of carb. Now it should be good to store till next use. I dont have to worry about diaphragm, etc
+davel8n saw was cold, that was first start in 2 years.
Screen is a spark arrestor.....and can be the primary reason it bogs. Nice Video!!
Had to do the same thing with my stihl leaf blower. Ended up just cutting the screen off altogether. It's ran great for 16 years now.
In case anyone is interested that "screen" is the "spark arrester" and is required by federal law.
Very true! However, one thing you could try would be to remove the spark arrestor for testing purposes only. Your test period may be 5 minutes, or may be an indefinite test period. Some places (national forest, etc.) will require them (and check for them.) Not just on a chainsaw, but a dirtbike, etc. etc. etc.
Thanks for sharing this tip. I would never have thought to check that screen.
n124lp 👍😁
Depends on saw, exhaust screen, spark plug, good clean fuel, air filter clean, been sitting carb cleaning, inspection. Runs bit funky carb possibly, then adjusting like here...
Great list of things to check. What I would like to see is how to test each of those things. Checking the air filter is easy to do visually. But how do I know whether it's the spark? Is there an easy way to test that? How do I know if it's the carb? Can I inject some gas in the air intake and see if it starts but then dies? Would that indicate the carb?
Yes... Check my other videos for starting troubleshooting.. I think I covered that on a snowblower video..
thanks, I'll check it out
@@Foxboss9 when it's not the spark arrester what else would cause bog down
Some say weak spark in coil is this correct
I've never heard of checking the exhaust screen and muffler. Hmm. Good info. Thank you.
Thanks Pal, this makes a lot of sense. Will check my saw for same problem.
When I'm done using my saw and I'm not going to use it for a while I always pour out the fuel and run it til it runs out of gas that way when I get ready to use it next time I can put in fresh fuel. Saves a lot of headaches later.
If the screen is carboned up (is that a word?), can you clean it with mineral spirits and a wire brush?
Good video! Thanks
Good and useful advice, well presented, thanks.
When I was a teen my dad had a monster Lombard Comango which we would cut cords and cords of wood every year in Maine with, he never ever got a chance to show me how to tune it, just sharpen it!
Over time that screen (spark arrestor) can rust apart and pieces could find their way into the cylinder. I blew a saw that way a few years ago. Chuck it. Thumbs up for the vid.
slofr8dan thank s for watching and sharing👍👍
Great explanation. You’re a wonderful teacher.
👍🙂
FOXBOSS9 you did a fantastic job on the video here. most videos drag out too long and gets boring.
👍😁
Fantastic insights and a great video, Now my interpretation: gGet rid of the screen, put it in the garbage and reassemble and never worry about that again.
Bad idea, that screen stops sparks from exiting the saw. Clean and replace or just replace.
Thank you so much for sharing this. I’ve pretty much done everything EXCEPT check the exhaust. I bet anything that’s the problem. Only been an operator for two years so I’m still wet behind the ears when it comes to this tormenting wretch. But I’m going out there now and fix it... thanks to YOUR HELP. Stay warm!!! I know I can now!!!
ZJhontu1 👍😁