Chainsaw piston scoring When you have an old saw with an obsolete piston, do you turn the saw into a wall hanger, or do you clean up the piston, install new rings, and run it? Obviously, this is largely based on the degree of scoring and whether or not the ring grooves are You don't always need to replace a 2 stroke cylinder. Mar 27, 2024 · If the rings of the piston hit the side of the cylinder, why does it matter that the piston is scored? It never hits the side of the cylinder If the rings are scored, cant you just replace them, and keep the scored piston? How to fix a chainsaw if it has scored piston and low compression. The saw was my father-in-law’s and Sep 19, 2023 · I know there's a few wood cutters on here and plenty with engine experience soI've taken the top end off my husqvarna 181se to inspect some piston scoring I could see through the exhaust port and wondered if anyone could offer a second opinion if they're reusable?! I've cleaned them up with Jun 20, 2025 · Unlock expert tips for fixing scored pistons in your Stihl O39 chainsaw. All of this damage was caused from running straight fuel in a STIHL MS360. It is safe if used in a safe manner but can kill you if you get stupid Jan 22, 2010 · YEP, that is what the tech told me yesterday, I asked him if the P/C had scoring he said no, I asked him why it failed, he said I don't know. My fuel mix is a little more oil than Dec 7, 2023 · I can’t help myself. The piston is shot, but the cylinder looks to have aluminum deposited onto it vs actual scoring into th casting. Enhance performance and longevity with these 5 expert repair solutions! Oct 19, 2009 · You will know when it's seriously scored. Maybe you could get by running it a ratio of 40:1 and just cut wood. The piston and cylinder walls are critical components of a chainsaw engine, and any damage to these parts can lead to reduced performance, increased fuel consumption, and even engine failure. I have it all disassembled and the piston and rings are gone but the cylinder has just a couple small scratches on it. Low compression, 90 and his boss said just replace the P/C. Is my chainsaw cylinder scored?? How to remove aluminum transfer from a cylinder!! - YouTube Chainsaw piston scoring - how bad is this?Huskavarna are excellent saws. I just scored an oem jug and piston kit off chainsawr in “good used condition. There is scoring on the piston and light scoring on the exhaust side of the cylinder. May 7, 2020 · If the scoring isn't horrible, and just some piston material transfered to the cylinder wall, etch the bad stuff with a tiny bit of acid, then sand it or quick hone somehow and be able to just replace the piston, do some crank seals because why not, and have a Coke. Question is how do you tell how much is too much? Jun 20, 2025 · Discover essential chainsaw tips to prevent scored piston issues and keep your tool running smoothly. 9K A subreddit to discuss maintenance and the repair of small engines, including mowers, tillers, chain saws, grass trimmers, and other small machines that make life easier. After pulling the muffler there's definitely some carbon build up and scoring on the exhaust side of the piston. A piston can look good but have thin worn out skirts, worn out or damaged rings, or damage to the top. The oil in the mix effectively displaces the gasoline that would otherwise exist, thus LOWERING the fuel/air ratio, which is a lean condition. You probably aren't looking at new rings until ten Feb 17, 2022 · Hey y'all, I have two ms-261's that are both showing some scorch marks at the top of the piston on the exhaust side. . Just do a Google images search for "scored chainsaw piston" and you will see what I mean. I left a note saying that if there was any scoring, for him to contact me before processing the order. Most of us have owned a 2-stroke with a scored piston and cylinder - be it a sled, a dirt bike, a saw or trimmer. All the way up the rings and into the upper part of the piston. Saw died. There are a lot of different pistons finished by the manufacturers in different ways so there are lots of variables. What am I missing here? How can you have low compression with no visible signs of an issue Sep 21, 2009 · I was recently given a husky 350 with a scored cylinder. I want to address any issue before I run saw Oct 11, 2016 · Hey Studs, When you inherit a saw with a toasted piston and or scored up cylinder how do you determine what caused the damage? I know many folks say stuff like this, "loaned to Wilbur and he straight gassed it---it was running super lean, or bad air leaketc, etc. It can be freed with penetrating oil in the cylinder. BTW 40-50 tanks isn't much use at all. Feb 9, 2008 · The fuel coming into the intake side cools that side of the piston and rarely does it score unless the fuel has no oil in it. In this article, we will discuss what causes chainsaw piston scoring, the signs that it is occurring, how to prevent it, the types of lubrication for piston scoring, the benefits of regular maintenance, and how to diagnose piston scoring. Aug 27, 2025 · Extend your chainsaw’s life! Discover 5 expert tips for scored pistons repair and keep your chainsaw running smoothly and efficiently. Jan 28, 2016 · I need some help please. Those vertical lines you are seeing is very likely normal (can't confirm 100% without a pic). Compression was @ 100psi and it had good spark. From reading on here, they seem to be well trusted, so I took a chance sight unseen. Scratches across the rings Jun 23, 2025 · Discover essential tips for fixing piston scoring in pro chainsaws. If these are present its a good sign also. If this is an XP model on Mon 1 Mike Homann Bad enough not enough oil in gas order a new one 5 hrs Mike Brewer Smooth thew pistons and rinis, fill in cylender grooves with jbweld , smooth out cylenerder mix gas oil a little heavy on Wed OilsOf Asgard Ring is fried Crank bearing likely gone too causing piston Jun 8, 2006 · This isn't a joke, but a serious question. Nov 20, 2012 · 2013 Stihl MS 362 with 18 inch bar; Cutting a holly stump about 16 inches, did not pinch. Most times only the exhaust side scores because it doesn't get the luxury of the intake side being cooled by the fuel mix. Jan 7, 2014 · What causes scoring on the intake side of the piston and cylinder? Does this effect the cylinder and piston as much as scoring on the exhaust side? Thanks But judging by the piston scoring I would say you probably need a new cylinder as well. A quick glance at ebay looks like you can get a aftermarket cylinder, piston, and rings for under $30. One of the most common issues is chainsaw piston scoring, and it can be difficult to diagnose and repair. 8K subscribers 1. I ordered and OEM piston and a few bits for the handle that were broken Feb 7, 2009 · Well I know one of the quickest ways to ruin one is to run without an air cleaner that will score a cylinder and piston super quick and you are correct not the right oil gas ratio can do it too. In either situation, a professional chainsaw mechanic or manufacturer should be consulted for thorough diagnosis and repair. Often what appears to be scoring is actually aluminum from the piston. It runs fine for 4 Do you have a blown, scored, seized or damaged piston or cylinder bore? Chainsaw or petrol / gasoline powered garden tool not starting or working? In this vi Nov 19, 2008 · That looks like pretty bad scoring to me. What's the best way to clean the aluminum off so I can tell whether the cylinder is scored. Hello R/Chainsaw, I heat with wood sometimes and am usually the go to guy in my friend group when someone needs a tree cut or if a storm knocks one over and im usually happy to help just for the free firewood. Mar 4, 2006 · Zero dollar “fix” for scored piston/cylinder Hi guys. In my shop I see this all the time and most of the time if it is just a scored piston you my able to Jun 15, 2009 · My question is: Is it typical for the piston to wear out but still have a decent cylinder wall? or do they go hand in hand, if one is gone, the other is too. I had it running hard making knife plate rips on rough sawn 8×8, which had no issues. Jan 28, 2014 · Scored cylinder - please advice Started by Coach, January 28, 2014, 05:40:11 PM Previous topic - Next topic 0 Members and 1 Guest are viewing this topic. I looked through the muffler and the cylinder and piston looked good, but rings seemed stuck (hard to tell). The piston above has severe scouring on the exhaust skirt with the heaviest damage on the clutch side of the piston. Pistons are not that expensive and many engines can be fitted with aftermarket versions quite inexpensively. Problem: saw all the sudden died when trying to warm up and died again when I actually put it in a log. In your quoted passage above, I May 2, 2013 · Picked up an 028 Super with a scored piston and cylinder on the exhaust side. Would a worn ring be the culprid of the 029? What would be the first easiest thing to check as to why low compression before teardown because there is no damage to cylinder/piston? This Post relates to piston failure in Chainsaws. I used a small screw driver to see if I could feel the Jun 21, 2025 · Discover essential tips for fixing piston scoring in pro chainsaws. What would cause this scoring? I presume an air leak would cause a lean seizure on the intake side. I was able to clean up the cylinder but will need to replace the piston. Just wondering what you all think Apr 20, 2002 · On the pisotn I was reffering to score marks caused by seizure or dirt ingestion. Read more! Feb 24, 2016 · The ms 260 i picked up few weeks back had a bad fuel line which must have been the cause of the lean condition. I know scoring is not good on any piston but am wonderig can you try to litley How to analyze the failed piston to determine the cause. But my question is can you save a scored piston. Recently looked at my chainsaw piston and noticed some scoring… has good compression and runs great. If the piston on your saw is scored and you have low to no compression, is the problem the scored piston or the rings? Is it always necessary to replace the piston and rings - what about the cylinder, or can you hone it out? Doesn't the compression come from Jun 16, 2017 · What are the symptoms of a scored chainsaw cylinder and piston? Hard starting and unable to properly adjust fuel mixture? What is Piston Scoring? Piston scoring refers to the damage caused to the piston and cylinder walls of a chainsaw engine due to excessive friction, heat, or improper lubrication. It has been having some trouble with glulams with epoxy, ripping down the middle about 8" for steel knife plate notching. It's like new cosmetically, even 95% of the paint is still on the bar, however the piston is scored. When new piston rings wont help. Myself, it would get a new piston. So I looked at the piston and it is scored pretty severely (pictures below), I Customer: Hello,I just want to know how can i detect if the chainsaw or strimmer cylinder or piston is worn and needs to be replaced with the new one even if theres no scoring it's visually clean and looks good condition. I was thinking about porting this saw one day but I was May 1, 2012 · While you at it, and since you have gone to this trouble, why not spend the $40 and put a new piston in? Rings are going to cost you $15 and you still have scoring on the piston. I've been making some cuts and rips in commercial framing. If your post gets flagged or not posted, send a message to the mods, and we'll review it. Won't start. I want to address any issue before I run saw Jun 8, 2006 · Time for some more cheap tricks. When i bought my 036 it had both the original hone marks on the cylinder and the cam grind marks on the piston. With some effort I can get the saw to start, and once I do I can rev it up all the way, but when I let off the throttle, it will May 19, 2013 · Lack of lubrication in the oil will typically score the piston all the way around and a lean running condition (not enough fuel or too much air) will typically score the piston just on the exhaust side. I will pressure and vac test befor i am done fixing it. Learn how to maintain performance and extend lifes Aug 8, 2024 · If the damage is severe, such as a broken piston skirt or extensive scoring, the piston may need to be replaced. Feb 29, 2008 · OK, I have a dumb question. What should I do? Dec 4, 2006 · Judge pistons by how well they function. Jan 25, 2020 · So I got this beautiful 181se for free from a friend, it has great compression and after a carb kit it's running like a top. Learn prevention tips and maintenance tricks to keep your chainsaw running smoothly and efficiently. The piston may have circular marks running around the piston left over from when they cam ground it. This kind of piston May 2, 2013 · Picked up an 028 Super with a scored piston and cylinder on the exhaust side. Hey r/chainsaw is this scoring worrisome? I got this Stihl MS311 about 18 months ago used. Discover 5 proven repair techniques to enhance performance and extend lifespan. Is there any measuring tools which can help to detect that? I've started to work with the chainsaws and still have things that i don't know Piston/Cylinder replacement: After you have determined you need to replace your piston and cylinder (generally by doing a compression test or seeing visible scoring marks through the exhaust port of your cylinder) here are the simple steps to do the repair yourself (this is a general guide and won’t apply to all models of chainsaws). Before using muriatic acid, look up some hazard info on it so you know what you are dealing with. I took it apart and this is the view. What's the compression? How's it cut in the field. Especially. Why is my piston scored on my chainsaw? Applies to 2 stroke, 2 cycle lawn and garden equipment, including weedeaters, trimmers, leaf I know this is OT. As to the piston itself, yours doesn't look too bad and could probably be cleaned up with fine sandpaper and steel wool. I have a Jonsered 2083 that I am getting ready to sell and while taking pictures of the piston and cylinder, it looks like scoring on the intake side of the cylinder. Same goes for the third listed cause, Lean----> score & seize. May 26, 2005 · The way I understand it, too much oil LEANS the mix. Scored chainsaw cylinders and pistons, can they be reused? The TOP 3 Secrets to Fixing Your Plastic Briggs Carburetor Don't throw that cylinder away!! Try and clean it!!! A Costly Mistake! Nov 30, 2023 · Rev up your chainsaw, and don’t let its scored piston hold you back! Learn how to hone a chainsaw cylinder in this expert guide. They still seem to be running well and have good compression (by feel not with a gauge), and I can't see any scoring in the cylinder or on the piston. Jul 27, 2013 · Bought this here on AS, to rebuild as a testbed for 441 top ends. I have an old Stihl 090 chainsaw and the saw seizes up after running 5 mins. I imagine a hone will be needed Aug 13, 2025 · Uncover the top 3 causes for a chainsaw piston hole. I thought I would show you a little experiment I did on an 036. Compression testing and peeking through ports will give you information but not always a complete picture. ” Piston looked good, but no pics inside cylinder. However some saws run just fine with scored pistons. My question is, now that Jan 1, 2012 · A piston that transferred metal onto a cylinder is usually ruined. Enhance performance and longevity with these 5 expert repair solutions! Mar 15, 2009 · I recently purchased an excellent condition Stihl 310 for $80. It doesn't make a lot of sense to rebuild a 25 year old saw with scoring unless the scoring causes performance issues. Is there a chance the saw will have good compression with replacement of the piston and rings? the cylinder walls do not look nearly as warn as the piston. The cylinder has very little little scoring at about the 1-2 oclock area, but the rest of the cylinder looks fine. Brought to dealer and was told it was scored piston Mar 14, 2004 · What causes pistons to score? Homelite XL123, looks like a beaten up rental saw, on exhaust side can see the scoring through the port, in general does it continue to progress or stay as it is, if taken care of, good fuel mix, not ran too hard? john Scored chainsaw cylinders and pistons, can they be reused? Tinman's saws 63. Sthil's ms250, ms290, ms440, 028, 064, 066 Couple tractors and old wood hauling grain truck lol May 23, 2021 · There is a lot of information on how to fix scored piston and cylinder on the forum, that is not my question. What you will need: Allen or Torx wrenches, flat and Oct 8, 2010 · I am getting a ms660 rebuilt and was wondering what caused this damage to the piston, as i don't know the history of the saw before i got it. The damage you see was caused in the moments before the piston "stuck," which seized the engine. Everything has passed on the Stihl engine check sheet and when hooked up to the MDG 1 it shows both at idle and full throttle running on Jul 24, 2025 · Chainsaw piston scoring - how bad is this?3 wks 2 Neil McDougall what did it digest? a sandbox 3 wks 1 Chris Cagle Bet you can use the cylinder with a lil work, I've seen worse 3 wks 1 Doug Wise Someone put in the wrong gas 3 wks 1 Mark Williams Stick a fork in it 3 wks Top fan Harold Caves New piston new head or junk it 1 mo 2 Driver Dalton Harold Caves Run that Bitch until It's Is your chainsaw running poorly or won't start at all? In this video I show you how to check for a scored piston and rings on your 2 cycle equipment like chainsaws and grass trimmers. " Yet, if you have no such I have a brand new saw that was started and run with straight gas. The piston looks great on the exhaust side. Whether you seized it personally and felt that sinking feeling in your gut, or bought it as a fixer-upper, there is hope to save your cylinder and Oct 14, 2023 · Other than improperly mix fuel/oil or straight gas, have any of you had a 500i end up with a scored piston and cylinder after only a couple hours of running. how to clean a cylinderthanks fo Mar 3, 2008 · Looking through the exhaust port cylinder looks like new and piston just the same even has those thin wear lines still visible on exhaust side, no scoring anywhere. The lack of lubrication on the piston has caused it to seize to the cylinder wall. The piston will look like someone went vertical on it with 24 grit sand paper. ucbyarn uwtg xxw ntnrg lyh moewe pgrkwlvc gvmhu rmq xphfq cjyqe podypd viy fyn chpyv