Brand new Stihl MS261C-M chainsaw ran without oil!!! Step by step disassembly and damage analysis

Hey everyone!!!
I'm sure a lot of you saw the original video ‪@donyboy73‬ and I did diagnosing this MS261C chainsaw. If you haven't, here is the link to get up to speed.
• Can My Apprentice Diag...
My last video showed the disappointing "new OEM" parts I received from eBay. I took your advice and shipped it back to the seller for a refund. If you haven't seen it, here is the link.
• Stihl MS261C-M repair ...
This video shows the tear down disassembly of my Stihl MS261CM chainsaw and a close up look at the damage that occurred when this brand new saw was ran without oil mixed in the fuel. What a shame!!! It's all good though, I may try and clean this scored piston and cylinder up, and I will see if ‪@donyboy73‬ has a spare piston and cylinder kicking around that will work until the pandemic is over and I can get my hands on a brand new piston and cylinder directly from the Stihl dealer!!!
Thanks for watching guys, and stay tuned for what's next!!!
Cheers,
Dave

[@hdhhc5555]

Man am I glad I found your channel on here. I have an o 26 and a Ms 261c. The new one works awesome. The older one needs the upgrade I watched on your other video. Very awesome!!! 👍👍

[@DavesSmallEngines]

Hey Darrin! That’s fantastic. I’m glad you enjoyed the video!!!

[@bunberrier]

Thanks, I found a 271 on the curb and its scored up inside. Already have a good saw but thought it would be a learning experience to get this one going too. compression very low

[@rxich]

Thanks for the tear down video Dave! I have an MS 362 C-M that I need to do a top end on also. I have been waiting for Dony to do a video on an M-tronic saw for a while now. I was worried that it was going to be much more complicated to get at the jug. Keep up the good work!

[@DavesSmallEngines]

Thanks Rich!!! Keep me posted with how it goes. Cheers!

[@carlmiller1034]

Great tear down video Dave. Hope you can get it running again.

[@DavesSmallEngines]

Thank you Carl!

[@donvoll2580]

Good day Yea new cyl. & piston. When I took small engine course, the 1 thing I could not get over was running at10,000 rpm little piston stops goes stops, all in 1 minute. Thanks

[@DavesSmallEngines]

Hey Don! Pretty cool eh?

[@bam18333333]

Ha, in a similar boat. Acquired one of these saws for free. Had a cheap ebay head on it. Was loosing compression at the spark plug.

[@Bungi81]

Hey Dave, i think I´d have a try on sanding / cleaning the cylinder... it´s broken anyway 😂😂 Perhaps you can have a try with a honing tool. I figured out, that it only cleans up the surface of the coating. Take care, Stefan

[@DavesSmallEngines]

Hey Stefan! I want this saw to be “new”... so I’m going to do something temporary until I can get new parts!!! Stay tuned!

[@Sensei948]

@@DavesSmallEngines Friend I fixed the 372 xp got a new Mahle piston. Compression after repair is only 140 psi? Will the compression increase after a few fuel tanks? what is the best way to use the saw after repair?

[@robinvermeulen4416]

With these new m tronic and auto tune carbs it is so hard to fix a broken carb yourself, because of the software that needs to be updated en link to the saw

[@DavesSmallEngines]

Yes it’s the way of the future isn’t it?

[@laurielammi3996]

I have accidentally run a virtually new saw on straight gas once while I was in a hurry to cut down a widow maker just before the grandkids came over to make it safe for them. I knew my mistake when the saw bogged down and stopped but it was too late. I knew better but in my haste, grabbed the straight gas instead of the clearly marked can of mixed gas. So even if you do know what your doing with a saw, mistakes can happen. Widow maker did get cut though.

[@tc3603]

Nice saw. That's mad that OEM parts are not available.

[@DavesSmallEngines]

$400 here from the dealer!

[@tc3603]

@@DavesSmallEngines big bucks Dave. A saw in that condition would probably be worth it if it were a keeper. It's probably 900 new

[@aussiehardwood6196]

Get a Meteor piston. They are close-ish to OEM quality, caber rings. Clean up the OEM cylinder with very fine sandpaper. Remove ALL piston transfer. You scored getting that saw!

[@DavesSmallEngines]

Hey there! It is a nice saw. I don’t love fixing a cylinder I want to keep long term.

[@Gary67242]

hopefully Don will be able to fix you up * fingers crossed..thumbs up my friend !!

[@DavesSmallEngines]

Well.... we’ll see. Stay tuned!

[@jimcherry2337]

Hi Dave, Did whoever used the saw prior to you say they ran straight gas in it? The reason I ask is I have the same saw and I even bought the overpriced synthetic oil to extend the warranty.. my saw/ cylinder and piston are scored as well and have been waiting for oem parts for weeks now.... so I have been without my saw for 2 months now and still wasn't given a reason for failure... the first dealer I took it to said It was unrepairable and they could dispose of it for me and I found out they never called stihl until after I got my saw back from those clowns.. the dealer that has it now has been waiting for parts and verified it is warranteed but didn't say what happened. I've owned chainsaws all of my life and know I did nothing wrong and I'm concerned about the new electronic carb may be at fault here, running it lean and overheating it... So here I am out over $620 US with no saw to use. Oh and yes my extended warranty is also running out with no saw to use. So I'd be hesitant to call the m tronic awesome as it may be the reason for my saws failure.

[@nheng6913]

Nothing awesome to see here. Just look at the m-tronic carb. When you realize that carbs are the most common thing replaced, this saw will be expensive to keep beyond warranty. Stihl dealers just replace carbs and are not about to repair or rebuild them. If you know you used the proper fuel and oil, do not let Stihl off the hook on this. Also, talk to Stihl in CT and do not depend on useless dealers for your final resolve. What did the dealer who said it was unrepairable offer you to let them "dispose" of it? What was your final resolution? I'm keeping fingers crossed on my new, non m-tronics saw.

[@petedebo6906]

Hey Dave hopefully donyboy found something you can work with I've watched your video I was thinking there has to be an aftermarket piston out there that will fit that's if the cylinder bore isn't scored beyond spec hopefully you get that saw up and running good luck to you

[@DavesSmallEngines]

Hey Pete! Check out my latest video!!! Cheers!

[@dujeamizic3588]

I would rather buy new cylinder and piston!

[@DavesSmallEngines]

Over $400!!!

[@andybecker2693]

If autotune and mtronic can sense air temp,barometric pressure, and fuel condition (among other things), then why can’t it sense if there is not enough oil and shut down the engine. I’m sure someone would rather pay for a diagnostic than a new piston and cylinder. Make it where the dealer has to reset the system before the engine will start .

[@DavesSmallEngines]

Hmmm, that’s a good thought!

[@JohnR9965]

Because they are in business to sell parts also.

[@DavesSmallEngines]

@@JohnR9965 hey true John!

[@anders1621]

How the hell did you loosen the bolts holding the carb ? I cant find any socket that will fit in those tiny holes

[@DavesSmallEngines]

I use a special thin walled Stihl 8mm socket tool!

[@STIHLFOREVER]

Hi Dave, the correct OEM cylinder ass'y part is 11410201230. It is avaiable here in Italy, but I think if I'll ship to you in Canada it will overcost more than 300 bucks at least. You may try to hone the cylinder with appropriate brush and replace just the piston (part n° 11410302031). The Stihl cylinders are very well quality, it will be work fine, let me know.....

[@DavesSmallEngines]

Wow! What a generous offer!!! I’m actually interested in this potentially... 300USD or CAD?

[@STIHLFOREVER]

300 USD, I don't know the canadian tax system. Death and taxes, damn taxes !!!!!!!

[@DavesSmallEngines]

@@STIHLFOREVER life’s guarantees!!! I will keep you posted if I decide to go that way. That is consistent with the pricing here. Thank you!!!

[@Anonyymsus]

out of intrest I checked that part nr 11410201230 is here in Estonia available for 192€. no shortage for stihl parts here.

[@DavesSmallEngines]

@@Anonyymsus that’s awesome. Thanks for checking!

[@joserivas4132]

Nice video!! Thanks for sharing your knowledge just like i said before we keep learning alot every time we see a video like this one!!

[@DavesSmallEngines]

Thanks for watching Jose!!!

[@larasea741]

Nice Video. Enjoy watching you and donyboy73. More please!!

[@DavesSmallEngines]

Yes sir! We will!

[@mattshaw6828]

Another great video, thanks Dave. Looking forward to seeing how it goes. I’m doing a similar project on my 461 I messaged you about and a TJ27 Kawasaki strimmer. Fun times!

[@DavesSmallEngines]

Right on Matt! Cheers!

[@rogermcdonald1607]

Hi Dave! That piston and rings definitely looks beyond saving. Cylinder maybe. Is that a home owner version or pro saw. Sad to see that happen but some people buy 2 stroke equipment and never get educated on how to care for them. Goodluck with your parts search sir! 👍🇨🇦🇺🇸Roger

[@DavesSmallEngines]

Hey Roger! It’s a pro saw. Totally worth saving. I’m not going to try and save it - I have a temporary option from Don that will hold me over until I can get my hands on some new parts. Cheers!

[@lovestihlquality1369]

Because I had extra bars and chains, my regular dealer let me buy 261c powerhead only w discount $500 out the door.. That was before all the shortages and price hikes.

[@ebfromwyoming4118]

wow Great video dave thks for sharing your knowledge sir hope donny boy can help u with parts

[@DavesSmallEngines]

He gave me something to try - stay tuned Roger!

[@420bodean]

I'm curious as to how the saw is coming along now after top end replacement. All that metal went to the bottom end & probably stuck to bearings on crank. Most time I would do a total rebuild if this were the case,, but like you said. Saw is to new & availability on parts is very limited. I'm in the process of the same thing with a customer's saw now. Still having a time finding crank & bearings. But cylinder big bore kits are available to now. I just hate to see a new top end go to waist over not being able to m as Ke it all brand new again. Thanks for the video though bud. Keep up the great work. :)

[@DavesSmallEngines]

Hey Jeffrey! I’m more of a fixer than a user so truthfully I haven’t put a lot of time on the saw. For what I have though, so far, so good!

[@420bodean]

I meant no disrespect to you bud by any means.. I was just curious how it was making out for the customer. I finished up the one I was going threw & my customer is very pleased. But he was thinking he was gonna have to buy a brand new saw as well. But for 300 bucks he is very happy. 😀 thanks again for the video & the reply back.

[@DavesSmallEngines]

@@420bodean hey Jeff! This is my own personal saw and I haven’t had much time on it. Lots going on!!! Cheers and take care!

[@josephponder195]

What did you use to get the 8mm out of the carb filter housing? My sockets won't fit, they're too fat

[@jimwesselman]

Dave, will you have to update the software when you put it back together? It would be interesting to see how that is done, guess there is some port that you plug into?

[@DavesSmallEngines]

Hey Jim! I’ll do an mtronic reset - I’ll make a video of it!!!

[@davidcoates3442]

Excellent video, thanks.

[@rpavlik1]

I've heard a similar thing is happening even with dryers. Whirlpool has been using the same basic motor for years, but there are no spares available because they're using the fewer that are being made now all for new equipment. You mentioned sanding out the cylinder, but not the piston: is it because the damage amount, or because the piston is softer?

[@mmholling87]

The cylinder is much harder than the piston. The material from the piston transfers onto the side of the cylinder because it's much softer. I've heard stories of people use maratic acid to remove the aluminum piston material from the cylinder walls.

[@DavesSmallEngines]

I’ve done that too - check out some of the vids I made on it!

[@rubengil3729]

Hola qué medida es la tuerca carburador de 8mm porque no me entra la boca

[@MrBaptiste003]

hello do you know the part number for a mtronic 3.0 ignition module on a ms 261 because on mine I have a 2.0 and I want to upgrade it to 3.0?

[@donyboy73]

I think I found something for you!

[@DavesSmallEngines]

Right on, Don!!!

[@jamesbainton]

@@DavesSmallEngines don't be fooled - he probably found something which comes with strings attached / another test. :)

[@stellarproductions8888]

@@jamesbainton And as Dave drives up to retrieve it, and Don sees him driving up on the security camera, Don twiddles his fingers like emporer Palpatine, and he says, "GOOOOOOD GOOOOOOOOOD" "Soon my plan shall be complete, and I will rules the world when I have rid it of ethenal forever!" HAHAHAHAHA

[@stellarproductions8888]

It sure looks like somebody smoked a piston and cylinder real good. What it needs is a new piston and cylinder. But I have seen you have good success by doing the sanding and acid trick. But that piston, I don't thinking sanding is going to fix that, especially with the frozen rings. Poor saw, id didn't even have a chance.

[@DavesSmallEngines]

It’s too bad eh stellar???? Sheesh. Don may have something for me though!

[@stevendamiani1447]

David nice job young man

[@DavesSmallEngines]

Thank you Sir!

[@adnacraigo6590]

Thanks for another good video.

[@DavesSmallEngines]

Thanks for watching!

[@ryanbruner8928]

If I remember right,Stihl says that their saws need at least 100 psi to function enough to be used? It could have been way worse.

[@DavesSmallEngines]

Oh yeah. Most I get are under 100 and no chance are they firing up!

[@sethhaun4440]

Dave they have a 500 i,,,at my co op 3 blocks away

[@DavesSmallEngines]

How much?!

[@sethhaun4440]

I m buying the 462 ..it's 1100 but getting some other bars .will be few weeks.though .im in peak Season and do taxes tommorow.

[@sethhaun4440]

It's a good price they might do it little cheaper if your just wanting the saw itself.and no bars exctra..god bless going to mow ..

[@sethhaun4440]

@@DavesSmallEngines my email sometimes has problems.so don't think I'm ignoreing it.if you do try it ..if not it's ok just wanted to help .can't stand the way theze corperations do us small guys.

[@sethhaun4440]

I beleive it was 1250.00 or 13oo

[@MCEdziits]

Compression test with no exhaust muffer? Interesting

[@nathenzuber4021]

In the future, there will be no gas saws. Lol

[@gtb7138]

I have a 036 ran on straight gas. Have new genuine barrel and piston. Would you recommend or is it normal practice to remove crankshaft to replace bearings? And connecting rod bearing?

[@DavesSmallEngines]

Nope - I wouldn’t worry about that. Change the piston and cylinder and slap it back together!!!! Just make sure the bad gas is purged out of the carb.

[@gtb7138]

@@DavesSmallEngines Thank you!

[@DavesSmallEngines]

Cheers! Keep me posted with how it goes

[@gtb7138]

@@DavesSmallEngines ok will do. I appreciate your advice thank you. Thinking maybe I should replace crankshaft seals and bearings. Big end bearing may be challenging. I have a 026 ex rental purchased rebuilt is there any way of knowing if it’s china parts?

[@1u5t1n]

500i is available pretty much everywhere in Europe.

[@DavesSmallEngines]

They seem to have fixed their supply chain issues!

[@gasperajdnik5627]

Good work 👍

[@DavesSmallEngines]

Thanks!

[@chuckuu9294]

Hi Dave good diagnostic. Well done. Keep up the good stuff.

[@DavesSmallEngines]

Thanks Chuck!!!

[@pwleppa]

Hello! Did you connect the MS261 to a computer to read the data? How many minutes was it run before it was ruined? Do you have the Stihl software?

[@DavesSmallEngines]

Hey there! No o didn’t. I don’t have the hardware or software.... yet

[@bennyhaha43]

Can that be done?

[@sethhaun4440]

If you want one there here.

[@DavesSmallEngines]

Yes sir!

[@shermankearns200]

Good compression but needs an upper fix

[@DavesSmallEngines]

Sure does!

[@MrBaptiste003]

Hello Dave how Many psi this sawchain Must have When she is new ?

[@DavesSmallEngines]

Hey Baptiste, over 180psi for sure!

[@MrBaptiste003]

@@DavesSmallEngines hello y have 190 psi on my 261 but my 462 have 150 psi it’s problème or normal ?

[@98fishingfool]

Can I have that cylinder ? Willing to buy and pay shipping?

[@DavesSmallEngines]

Send me an email at [e-mail]

[@nashguy207]

Maybe you can find some after market parts

[@DavesSmallEngines]

No aftermarket for the slant fin 261cm yet!

[@dujeamizic3588]

You need new cylinder and piston!

[@stellarproductions8888]

Yes he does, but Lex Luther looks at his watch, and then shakes his head no. Its gonna take months, I am going to fall asleep before those parts get here. Oh man, what a world, what a world. :D

[@DavesSmallEngines]

Yes I do!

[@seanmcgillicuddy956]

Hmm another HOT saw... do these come from the same person ... Good luck getting the right parts...

[@stellarproductions8888]

Ya, I say it was so dam hot, it burst into flames, it was that hot I'm telling ya. Crispy fried by stupafied. :D

[@DavesSmallEngines]

Crispy spicy!!!

[@DavesSmallEngines]

I’ll try!

[@steveartese9014]

They gave the parts in Ottawa but it's 390$ 😳

[@DavesSmallEngines]

That sounds right!

[@steveartese9014]

Why didn't the person read the owners manual before use, asking for a friend. 😂

[@DavesSmallEngines]

No kidding!

[@nheng6913]

I call pure BS on the lack of availability of parts for a pro level machine. Why do you think we paid top dollar for the pro level? The magnesium crankcase doesn't do diddly if any critical component can't be found. I asked my dealer (a good dealer) about this and yes, if it's not in stock, you will be without a tool until Stihl gets parts. This is unacceptable from Stihl or any others in the same boat. And my theory on the C, C-M as a design engineer, is that the firmware runs too close or beyond the edge of lean for some set of parameters that it is looking at. Maybe you pulled it out of a freezing vehicle or one whose interior is at 150F. The thermal mass of the engine, block and carb body will tell the sensors that the thing is either freezing or burning ... and will do this until air flow normalizes the temperature. Likewise for whatever else it looks at (altitude? barometric pressure?, etc.). I'm very happy with my new MS261 ... without any stinkin electronics or processors or sensors :-) :-) :-) Running Saber 50:1, Ultra is on the shelf for now. One last theory ... is it possible that in addition to running straight gas it was run with the air filter still on the bench, perhaps under a towel? This would suck in all particulates in the area. I clean my saws with compressed air and what has concerned me lately is that pressure of the air could blow stuff into the exhaust side. Depending on piston position, this could either coat the piston with abrasive or fill up the crankcase well with it for continued distribution. Sorry for the long post, this stuff gets me going.

[@geoffeves3517]

There is no way you fit that regular diameter 8mm into the face of the carb filter housing😂

[@josephponder195]

I'm having the same problem!! Help. I can't find any thin walls in my town. Any other ways to get em out? Or just a special kind of socket

[@williamevans6554]

@@josephponder195 snap on deep 1/4 drive fits

[@shermankearns200]

t27 yikes LOLOLOL Meteor piston for sure

[@DavesSmallEngines]

I’d like to go OEM!

[@theDunn05]

It’s not OEM, but they’re rock solid parts for sure. lilredbarn.net

[@DavesSmallEngines]

I’ve been there - good stuff. Just nothing for the slant fin 261cm!