Stihl MS261 finally on my bench

[MEATSAW]

Some may recall a thread I put on here a couple weeks ago questioning whether I should get a 261 with 155psi compression or not. Well I did it. For $300 bucks I think I got a helluva deal. Sure its definitely not a shelf queen, but it oozes quality. There are a lot of naysayers on here regarding the 346 vs 261, but one thing usually forgotten in the discussion is build quality, ease of use, and resale value. I've never owned a 346 (one of these days!) but I am very impressed with the 261. The only negative comment I have about it is the carb limiters. I hate being limited -- and apparently these are a real PIA to remove. Oh well. I have it wearing a 16" bar and 3/8" LGX chain.

I checked the piston out and there was some very subtle scoring on the piston on the exhaust side. It didn't affect the rings. Perhaps this is the reason for the compression reading to be a tad lower than some reported values on here for a NIB one. I plan on running it till it drops to 140-145psi and then replace the piston.

I got this to replace an 028 Super that I sold about a month ago. Definitely a step forward!

 

[H 2 H]

Good Job :msp_biggrin:

 

[0zarks2]

Grats on the saw. I've got a 261 and a 346. It's 6 of one and a half dozen of the other IMO. I think they're both bad ass in their own right. I know I don't plan on getting rid of either one of mine. Enjoy your new saw.


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[MEATSAW]

Oh and I don't understand why they used the mini-spline clutch drum. Not that its an issue, but it seems odd. And of course Oregon doesn't have a PowerMate system for it yet. Thankfully I got a handful of 3/8-7 mini spline rims.

 

[deye223]

pull the limiters before you run it , thats probably the reason for the slight scoring
cheers congrats and good luck:byebye:

 

[SawTroll]

Oh and I don't understand why they used the mini-spline clutch drum. Not that its an issue, but it seems odd. And of course Oregon doesn't have a PowerMate system for it yet. Thankfully I got a handful of 3/8-7 mini spline rims.

Likely to sell more of their expensive mini-spline rims - but as a bonus you can put a picco rim on it.

I assume there is a Powermate system in regular small 7-spline for it?

 

[H 2 H]

Heck put a 3/8" 7 rim on it

 

[MEATSAW]

Yeah thats what I am going to do. I got the carb properly set up and I worked over the muffler. After playing with the carb I am fairly certain that the low side was set too lean. It might have came that way from the factory (I'm the 2nd owner), but who knows. It was tightened all the way in, which even according the manual is not right. I had to back it out several turns. I also had to back out the high needle a bit richer than the limiter allowed. Now its all tuned up and ready to go.

Just for future reference, is there a good aftermarket piston kit? Or should I stick to OEM?

The cylinder has a "B" marking on it, does that mean anything in particular?

 

[H 2 H]

Meatsaw did you get my pm and did you try it

 

[MEATSAW]

Meatsaw did you get my pm and did you try it

Yea I did, it wasn't as bad as I thought it would be. If I hadn't of opened up the muffler it probably would have been okay, but I had to richen it up a bit more than the limiter would allow. I really appreciate it!

 

[nmurph]

Scuffing means there has been some transfer onto the cylinder walls. Best to pull it and clean it up good. You can probably smooth the piston and re-ring it.

Are you sure your seeing transfer or are you seeing witness marks?

 

[Rudolf73]

Thats a good deal you got there.

Regarding the carb limiters - do a search as there are a few thread on it. And they can simply be adjusted (as the stihl dealers do)... there is no cutting/modifying required.

 

[blsnelling]

Scuffing means there has been some transfer onto the cylinder walls. Best to pull it and clean it up good. You can probably smooth the piston and re-ring it.

Are you sure your seeing transfer or are you seeing witness marks?

I STRONGLY agree. You're WAY better off to just pull it off and make sure it's right.

 

[MEATSAW]

So the scuffing is indicative that material from the piston transfered to the cylinder?

How would I smooth the piston?

What rings should I get?

Thanks for the help. This is new territory for me.

 

[David (saltas)]

there are about three different ways easiest is a 2mm Allen key

http://www.arboristsite.com/chainsaw/173328.htm

 

[nmurph]

So the scuffing is indicative that material from the piston transfered to the cylinder?...

If it is scuffing, then yes. It is also why the compression is a little low from where it should be for such a new saw.

How would I smooth the piston?...

I would lightly work with a 400 grit sand paper, then a little steel wool.

What rings should I get?...

Take them out and measure. You may be stuck with OEM. If you can find Caber rings in the correct dimension they will be fine.

Thanks for the help. This is new territory for me.

My pleasure.

You may also need to read up on cleaning tranfer from cylinders.

 

[MEATSAW]

Looks like I am going to bust out my folding table so I can do it in my A/C and get this thing pulled apart. I hope my Stihl dealer can hook me up with some OEM parts for not ridiculous $$

I will keep you guys abreast of everything, since I will surely have more questions as I go about this.

Thanks again to the helpers and enablers on this site.

 

[SawTroll]

....
Take them out and measure. You may be stuck with OEM. If you can find Caber rings in the correct dimension they will be fine.

..... .

I believe it is better to only install the upper one?

 

[MEATSAW]

So today I was able to pull the piston and cylinder and I am glad that I did. Everything was a lot worse than I first thought. Here are some pictures of them. What do you think?

I am probably going to replace the piston and rings, but I definitely think the cylinder is just fine. Unfortunately all I can find for a piston kit is a Golf on eBay, and they have dubious reputations on here. I will put in a call to Stihl tomorrow and get a price for OEM :help:

 

[Raganr]

Unless coming from a reputable builder, I think I will pretty much assume any used saw has a scored piston and cylinder from now on. That looks a lot better than the saw I recently purchased.