Chainsaw with scored piston. How?

[Buxus]

2013 Stihl MS 362 with 18 inch bar; Cutting a holly stump about 16 inches, did not pinch. Saw died. Brought to dealer and was told it was scored piston. Initially dealer said it must be bad gas, which it isn't. Then he said must have overheated. $500 repair on a $725 saw. I'm pissed as ****, but don't know what to do.

Saw doesn't see a ton of work because I mostly use my smaller saw as I do mostly branch clean up on my property. Don't heat with wood. The big saw is for the occasional big tree down. So the saw is not beat up at all. Doesn't get used a lot, but when I need it, I need it.

Always used premixed gas in a can, chain always oiled and sharpened. Gets about q2 yr service at dealer, but only sees a few hours of work a year. Not only don't I lean into it when cutting, but I probably can't as I weigh 135 lbs. The dealer said cutting smaller trees with it than the blade is long (in other words not having the blade buried) allows it to spin too fast and overheat. Is this true?

Thoughts? I'm unsure about buying another/getting fixed when I don't know what I did wrong in the first place.

 

[mcfarmall]

If the "cutting smaller trees than the bar length" was true, then Stihl would be making saws with 6" bars. I call BS on the dealer. Unfortunately the cost of repairs is >50% the cost of a new saw, so with that train of thought, I'd keep it for parts and buy a new one.

I mix my own fuel with ethanol free "rec gas" and run 40:1 and never had any problems.

 

[Diggin It]

It really doesn't take much to do that I don't think. I had one seize up on me ( a cheap Homelite). I'm guessing I overheated it. I was able to get it freed up and run it for quite a while before it died for good.

Don't really know what happened to yours. But this is why I don't buy high dollar items. When they fail, they cost more to fix. My first two were Homelite rebuilts I got for under $100 and when they died, I didn't worry about fixing them. The second one I was also able to bring back for little money however and am still using it to an extent. Most recent is a Blue Max with two bars and chains for $150 or so.

Have you looked into parts to try and fix it yourself? You may be able to get a short block, piston and ring kit from a third party supplier.

 

[BigBlue1]

If you're handy with mechanical things perhaps consider rebuilding it yourself. I rebuilt a McCulloch Pro Mac 800 that had a chunk of something go through the cylinder. Piston was shot with a major gash in it that chewed through the rings too. Cylinder had some scratches. I had a local cylinder head place polish the scratches out (didn't take much - I think they might have been more from aluminum transfer than actual scratches) and I bought and installed a new piston. If one can do that with a 25+ year old Mac I'm sure the parts are available for a modern Stihl. Chainsaws aren't that complicated... just lots of parts. There are probably good forums online with Stihl gurus that can give you tips on disassembly & reassembly. You'll save a ton of $$ this way.

Rob

 

[ruffdog]

What could of happened:

Maybe there was a vacuum leak that allowed the saw to run lean and hot. This can happen on new or old saws. Is/was a pressure/vacuum test done on the saw to find the cause and to prevent it from happening again?

For 2-strokes, the big danger with running ethanol E10 fuel is what happens after the fuel absorbs water. As the ethanol absorbs water, there is a point that the gas/h2o/ethanol mix will want to separate from the 2-cycle oil. If this happens, at some point the engine will be operating without oil in the fuel mix.

Being that the saw has a few years on it, most times the carburetor diaphragms can get stiff and not pump enough fuel, especially when worked.

Maybe a cracked fuel line allowing air to lean the air/fuel mix.

Was the air filter doing it's job by not allowing dirt past it?

 

[EddieWalker]

I had this happen to a Husqvarna that was less then two years old and probably had about 20 hours on it. Dealer said that it would cost more to fix then it was worth, so I decided to buy cheap saws since they didn't last very long. Cheap saws where too cheap and a total waste of time. I was taking them back after just one day of trying to get them to run, and stay running. Then I decided that Husqvarna was a cheap saw and that I had gone in the wrong direction in my thinking and bought my first Stihl. I have several of them now, but then discovered Echo, which I like even better!!!

 

[ArlyA]

Buxus, Sorry to hear of your grief. I can't tell you what happen to your Stihl but I do think they are a quality built machine, but I can tell you what happen to an Echo* we have. It was about a year old and we were in the fielding doing trail work. We stopped for a break and after that, it wouldn't run worth a hoot. It wouldn't spool or rev up which was strange, since it ran perfectly just 15 minutes earlier. We took it back to the dealer who tested it and called Echo who suggested doing this and that to find out what happened. They eventually figured out the cylinder was scorn and they gave us a new unit since it was a year + old. Point is, they didn't know and couldn't figure out what happened, but that's an answer we can sometimes get. It can happen....

* We have several Echo's and use them for many, many hours each year.

 

[bigsilver]

Replacing the jug and piston on a pro series chainsaw is not a very difficult job. A quick search and a jug and piston is <$100. Plenty of write ups and videos on the subject if you don't know where to start. It's up to you, but I would at least watch a video before making a decision to have the dealer work on it or buying a new saw. I agree with ruffdog about the saw leaning out is probably the reason the piston was scored in the first place.

 

[adventure bob]

Couple of questions: is it still under warranty? How many hours on it? If its still under warranty, ask the dealer to provide the results of the leak test before he tore it down. If he did not leak check it then you have a viable claim with Stihl. He has to prove something you did was the cause of the scored piston before he can deny your warranty claim. If he says it was bad gas, ask him how he knows that. If he did not have the gas tested that cannot be used as a denial basis. "it looks bad" wont hold up. I have a husky that I went round and round with the dealership and finally the husky rep acknowledged that the dealership didnt do due diligence before denying my claim. Mine turned out to be an air leak in the transfer cover gasket. However the dealerships first answer was bad gas. I said prove it. We have this thing called the Magnuson act which governs consumer protections under warranty.

 

[Citydude]

I keep hearing very good things about Echo saws. Our home depot sells them.

 

[ericm979]

The < $100 cylinder + piston are Chinese clone parts. You can get them from hlsupply or huztl. The quality can vary- some clone parts makers do a better job than others. There's also non Stihl aftermarket parts like Metor. They're more expensive than the Chinese clone parts but less than Stihl.

Often after a seizure the cylinder coating is not damaged and you can clean the deposited aluminium off with acid. Dealers don't do that. The dealer's quoting replacing the cylinder which is the most expensive part.

Lack of oil can cause scoring and seizure as can poor oil. So can running the saw too lean. If you adjusted the carb to run correctly when the ambient temp was high and then cut when it's cold without richening the carb setting it'll be lean. The marks on the piston will be different for an oil related seizure/scoring than a lean seizure but you need to remove the cylinder to see.

 

[Oldpath05]

$500.00 to fix, forget it. I'd take it apart my self and order parts off ebay, or take it to another saw dealer and trade it in.

 

[bigsilver]

The < $100 cylinder + piston are Chinese clone parts. You can get them from hlsupply or huztl. The quality can vary- some clone parts makers do a better job than others. There's also non Stihl aftermarket parts like Metor. They're more expensive than the Chinese clone parts but less than Stihl.

Often after a seizure the cylinder coating is not damaged and you can clean the deposited aluminium off with acid. Dealers don't do that. The dealer's quoting replacing the cylinder which is the most expensive part.

Lack of oil can cause scoring and seizure as can poor oil. So can running the saw too lean. If you adjusted the carb to run correctly when the ambient temp was high and then cut when it's cold without richening the carb setting it'll be lean. The marks on the piston will be different for an oil related seizure/scoring than a lean seizure but you need to remove the cylinder to see.

You are correct about the Chinese clone parts. I only use Stihl OEM parts now unless I am putting in a big bore kit. But my first chainsaw rebuild was with clone parts (it lasted a couple of years before I put OEM parts back in it). A OEM piston should run about ~$75, a cylinder will be another ~$250. I agree the cylinder may be salvageable but I would have to see it before making that call. Unless the chainsaw is ran fat, a saw really should be adjusted at least every time it is ran at different conditions. Shoot I know guys that adjust multiple times a day.

 

[Coyote machine]

Try arborist.com and or several other sites where professional sawyers hang out. They'll talk about saws until the cows come home, and then some more.

I have 7 running Stihl saws, and one parts saw waiting to be used to fix one of my favorite Stihls that decided to take a swim in my pond, then I saved it, until it eventually wanted a rebuild.

All the things said about lean mix and the possible causes of it are accurate, including the need to shake the fuel oil mix every time one fills the saw's mix tank. Shake both the mix container AND the saw to make sure the mix is mixed.

The dealer is blowing smoke up your ... about having to bury the bar into an 18" tree in order to keep the saw from burning up. I take it your saw is off warranty? Were you using Stihl's ultra oil- which I believe doubles the warranty time if bought and used since purchase.
Maybe try a different dealer and see what they diagnosis as the cause/effect.
Do you run out the mix in the saw when not in use/off season? If not do so, and add some stabilizer to the fuel you are running through the saw to coat the parts that can be affected by moisture, etc.

I've had cracked fuel line(s), impulse lines and diaphragm issues over the years on various saws; it's not a brand thing, more a use and failure of the cheap azzed components used on today's equipment, regardless of brand. And of course the ***** fuel available these days. I use non-E-10 fuel only and don't store it over 30 days tops.

Stihl is a great brand, but for occasional use homeowner saw(s), an Echo might better serve your needs of price point and ease of use. Echo makes great equipment, which is reasonably priced, especially when an annual saw sale happens. They're generally easier to start than a lot of Stihls, and are very popular among those who don't use their saw to make a living, i.e. occasional use, like your use pattern.

If it were mine, I'd probably consider a self rebuild, vs. the dealer, and chalk it up to experience, for future reference, AFTER having a different dealer give you their opinion of cause/effect on the saw's future.

If you get the same diagnosis, either keep it on a shelf and buy a new saw like the Echo, and forget the damaged saw, or invest the time/money to rebuild it, knowing it may not be as good as it once was. Plus, if you don't find the cause of why it failed it's doomed to fail again...

The money you spend and time to rebuild the Stihl, you could buy a new saw and start fresh. If you have the cash to buy new, that's what I would likely do.

Oh, you don't have to weigh 180-250 to bury the saw chain; a properly maintained bar/chain will pull the chain into the wood and cut like crazy just holding onto the handles. Let the saw do the work, forcing it into a tree is not the way it's done.

 

[EddieWalker]

I keep hearing very good things about Echo saws. Our home depot sells them.

The dealer that I bought mine from is also a Stihl dealer, along with a few brands of lawn mowers. On the wall to the right is all Stihl, and the wall to the left, it's all Echo. He really likes the Echo, but will sell you what you want. He is the one that talked me into trying Echo, and I'm really happy that he did. I don't know about the Home Depot models, the price difference wasn't big enough to take a chance on what they have in their store over the dealer that services them for me.

 

[Stubee]

Man, that sucks. My MS260 has had exactly one problem in 15 or so years, when I jumped the chain trying to clear enough limbs outta swamp balsam to get my saw in to cut the trees. That’s it. It’s never been to the dealer since I bought it except when I need a new oil or gas cap (to make sure I get the right one). I ran it most of that time in regular pump gas with Stihl oil, just switched to rec gas this year. I do shake the can before adding it, but that saw rides in my half ton most of the year and always runs fine, even after sitting for months. I love it.

It sounds like the problem wouldn’t be fixed with the rebuild kit like others have said; something else may have caused it to fail. With the advice on the need to bury the bar fully I’d take it to another dealer and get a 2nd opinion.

 

[ruffdog]

The local BIG tractor dealer needed a Stihl mechanic so one of the Parts dept underlings said they would do it. Not all small engine mech's are "experienced".

 

[blacklion66]

If the "cutting smaller trees than the bar length" was true, then Stihl would be making saws with 6" bars. I call BS on the dealer. Unfortunately the cost of repairs is >50% the cost of a new saw, so with that train of thought, I'd keep it for parts and buy a new one.

I mix my own fuel with ethanol free "rec gas" and run 40:1 and never had any problems.

Darn good advice!
I suspect the scoured piston wall was a result of ethanol gas mixed with the correct oil but the gas had been setting in the gas can for several days. I'm kinda old school from back in the days when chainsaw oil would separate if it had been mixed just a few days. "shake the can every day"☺

 

[Citydude]

The dealer that I bought mine from is also a Stihl dealer, along with a few brands of lawn mowers. On the wall to the right is all Stihl, and the wall to the left, it's all Echo. He really likes the Echo, but will sell you what you want. He is the one that talked me into trying Echo, and I'm really happy that he did. I don't know about the Home Depot models, the price difference wasn't big enough to take a chance on what they have in their store over the dealer that services them for me.

I agree with dealer sales over the big box stores. My other saws I bought at dealers.

 

[DieselBound]

I know the pain. I cooked a Husky 562xp*. Totally my fault: worked it WAY too hard when ambient temps were in the 90s. The earlier saws were more susceptible to the damage that I encountered. However, often times there's an engineering defect (manufacturers won't own up to them though) that is quietly addressed through later models. Some of this can be seen by newer revision numbers on parts. I know that Husky was aware of heat problems in the earlier 562xps as they subsequently made changes directly addressing this issue. I liked the saw too much to not get another one: I bought a newer one, and this time I had it mildly ported to mitigate any heat issues due to running too lean. I've also gone to 40:1 mixes and running ethanol-free fuel.

I've thought about rebuilding my dead saw but am still on the fence. I'd have to, in likely addition to a new cylinder and piston/rings, replace the carburetor (one of the changes made to deal with overheating issues). I'm slowing down, in which case my existing saw isn't likely going to be exposed to my previous run-you-into-the-ground paces.

Cooked that first 562xp on this trunk (was running 50:1 at that time- not sure if I was running ethanol-free, but now am):