Well, I did it. I ruined brand new MS260

[ciscoguy01]

Yip

As I sit here with that hang-dog look on my face, wondering how I'm gonna keep my girlfriend from finding out I just fried my new saw...Insult to injury, I can see it coming! Like a freight-train.

Nah...you guys are great. What a community of of nice people this is.

I think I'm gonna go pour myself a glass of bourbon and think nice thoughts for the holidays...

still shakin' my head-

james

As the greatest man on earth once said... "BEH!!! Fu|< it dude, lets go bowlin..." Live by those words ma brotha.

 

[RaisedByWolves]

Yeah man, no blame falls on you EK.



I like your choice of mix ratio.

 

[Sprig]

So am curious, what in the world would cause that bad of scoring, yikes!, if it was not a hunk of plug metal what else could it have been, like are there any wee carb parts that could have fallen in there? Could a ring have hooked the edge of the port? From the look of the grooves whatever it was took a few rides up 'n' down, just plain nasty and I feel for da man. Surely a bad mix wouldn't do that!?! Am wonderin' in wonderland.

 

[ol'homey]

James,
You put the oil in and then the gas right? Did you shake the can afterword? It really does look like straight gas to me. Question for the experts: How do you lean out a saw enough to cause this damage with the limiter caps still in place and him trying to turn the screws CCW to richen the mix?
Our choices are straight gas or lean seize right? I don't see how putting a bar on the saw is going to fix either one of those problems. IOW if it's lean turning 14k without a bar isn't it going to be lean at 13.5 with a bar?

 

[drmiller100]

he leaned it out. that is really classic lean seize.

melted aluminum down the exhaust side fo the piston, covering the rings. when you pull it apart, the exhaust issues will have jammed the intake side, but the exhaust side will be the worst.

lakeside's offer was way cool. this isn't a big deal. teh crank is fine, case is fine, all the plastic is great.
like they said, 100 bucks, down the road better then new.

 

[drmiller100]

From this thread

http://www.arboristsite.com/showthread.php?p=537786#post537786

Here is what I posted.

so that's fine for jetting it wot with no load.

How do you jet it for cutting wood?????

 

[Patrick62]

everybody Scre3s up once in awhile

I drilled out the muffler of my 260 with less than 2 tanks thru it.
It just seemed the right thing to do.

The low setting isn't changed, but the H needs just a touch more. I believe I am right up against the limiting cap on that one. Saw runs fine, 30 or so tanks thru it so far. The air filter is my biggest gripe.

I prefer to try and adjust the H with the saw in WOOD! You get it close in the shop, but then put a load on it.

Oh, not to :deadhorse: but I run 40:1 for some reason. Put a new cylinder and piston on it, clean the snot out of the lower end. It will be good to go!

-Pat

 

[sawinredneck]

I think what happened is he took off the bar after the muffler mod (which raised the RPM) ran it without the bar and chain WOT, which raised the RPM more) while trying to get the screwdriver lined up with the carb adjusters, which took too long. So with all of the increases in RPM, and being held there too long, eithe a cir-clip came loose, or it just got too hot, either way, I believe it was all due to over-reving.
Andy

 

[ozarkjeep]

The pics look like a 4 corner seize to me.

this happens sometimes when you dont warm the saw up, the piston and cylinder expand at slightly different rates.
more common with forged pistons than cast. ( in other applications at least)

New to saws, but Ive messed with alot of 2 strokes.

I would not be surprised to see some signs of Detonation, and errosion of the top of the piston at the exhuast port as well, IF it is a lean seize.

 

[Lakeside53]

so that's fine for jetting it wot with no load.

How do you jet it for cutting wood?????

The WOT method (with a chain load) is JUST a reasonable approximation of the correct mixture and to make sure you don't exceed the max rpm. If you're "4-stroking", you're conservative mixture-wise. If you want "a bit more" then either guess or tune in the wood (under load). For in-the-wood - either do timed cuts or take the two person-approach.. . For most guys, just set it to "4-stroke", make sure the max rpm isn't exceeded, and leave it alone.

In this case, the limiter cap (only one on this carb) was not removed. It's shipped from the factory set pretty much to the max rich allowed, and it's not possible to make it richer without removing the cap. I suspect the carb got tuned leaner, not richer...


For those of you that haven't picked up on it yet, this saw has a 44.7mm bore.. not the commonly available 44mm.

 

[litefoot]

so that's fine for jetting it wot with no load.

How do you jet it for cutting wood?????

I don't race my saws, I only cut firewood, so I personally don't need to be on the extreme lean edge of a carb tune. I like the added margin of safety of a no load tune, especially when I'm in and out of the wood a lot while limbing for example.

I may be wrong, but it seems to me that tuning a saw in the wood would tend to create more situations like the one that started this thread. Peak RPM in the cut, but overspinning out of the wood.

 

[SawTroll]

I think what happened is he took off the bar after the muffler mod (which raised the RPM) ran it without the bar and chain WOT, which raised the RPM more) while trying to get the screwdriver lined up with the carb adjusters, which took too long. So with all of the increases in RPM, and being held there too long, eithe a cir-clip came loose, or it just got too hot, either way, I believe it was all due to over-reving.
Andy

Just a thought; Could steel shavings from the muffler mod have been sucked in???

 

[deezulsmoke]

Sorry to hear about your new saw. It looks like no pre-mix from the pic.

 

[JamesJems]

The pics look like a 4 corner seize to me.

this happens sometimes when you dont warm the saw up, the piston and cylinder expand at slightly different rates.
more common with forged pistons than cast. ( in other applications at least)

New to saws, but Ive messed with alot of 2 strokes.

I would not be surprised to see some signs of Detonation, and errosion of the top of the piston at the exhuast port as well, IF it is a lean seize.

Well everyone, I'm going to take up Lake on his most generous offer to help me out in this case. And I'll learn quite a lot in the process. Tell you what. I'll take pics as we tear it down. We'll be able to see exactly how one destroys a saw in one easy step.

By the way, there is 50:1 mixed gas still in the saw. I'll drain it down at Lake's place in a couple of weeks. You can take his word for it. Stay tuned....and thanks for all your support.

Oh, and I told my girlfriend. Had to. She'll be coming down to Seattle with me when I take my say down to Lake's place. (Although I imagine I'll have to drop her off at the mall or she'll elect to sit in the car while we take this thing apart.) I sat her in front of the computer and told her to read the thread. And then gave her one of my looks when she wanted to say something after. NOT NEEDED.

But, I woke up in a better mood.

james

 

[ASEMASTER]

I've been there

that picture reminds me of my 3cyl. ultra when it started to break down on the other side of the lake and I made it go another mile to the parking lot. last day of good warm riding, ha I had to clean the aluminum out of the muffler . three new pistons and rings , seals and we were off again only to have no snow last year. good luck it's an easy fix.

 

[timberwolf]

Thanks for sharing, always lots to be learned when things don't go right.

I am sure Lake will fix it up well for you, Something maybe to put some thought to is going with a bit more oil in the future 50:1 IMHO is just a little too close to the edge, great to get the polution numbers down, but leaves little safety margin.

40:1

I run 32:1 but am pushing the saws above stock RPM or for milling.

 

[MikeInParadise]

Just a thought; Could steel shavings from the muffler mod have been sucked in???

I admit that this was my first thought too. Was the muffler off the saw when the holes where drilled?

It is a bummer! Not that I have ever screwed up a brand new tool the first time I used, well not not more than twice anyways, ok would you believe 3 times?

Life is a learning experience and if you aren't making mistakes you just aren't learning!

I learn lots and lots every day!

 

[stihlatit]

Hey James

Lift that head high and know that you tried. I know how you feel as I remember well when I blew a piston in my 066 last August. I am attaching the thread of that escapade. There were two of us that did the same that week as you will see. The other member was Adrpk. He started the thread. I posted in it as well. There are pics there from both of us.

http://www.arboristsite.com/showthread.php?t=34925&highlight=066+lean

Also know that you are hanging out with some of the classiest guys that you will ever want to be associated with but I think you have allready noticed that. This community helped us both in various ways as you see in the thread. Lakeside is a special person that continually gives of himself as he is to you. He did the same for me. I through him and the help of this community was able to rebuild my 066. Although I am mechanically inclined without this community I would never have attempted the rebuild. It was very successful and the saw runs like a champ. I thank this community for that and especally Lakeside. He will not do you wrong.

Chalk it up to experience and do not it knock you off the horse for good. Read more as to what happened to you and how it could have been prevented. Build your confidence back and stay with it. Read lots and ask lots of questions before you attempt something. Use the search and the knowlege of this community. If it does not feel right ask before you comit yourself is a good rule of thumb. Better luck in the future.

Kind regards.

 

[Kneejerk Bombas]

For those of you that haven't picked up on it yet, this saw has a 44.7mm bore.. not the commonly available 44mm.

OK, I'll bite. How can you tell?

 

[timberrat]

burnt pistons happen

i know what it feels like to burn up a new saw . last year burnt up a husky 55
last year. it was a cold seizure. so learned a lesson and moved on to better saws.