lots of carb built up in the muffler MS260

[teakwood]

I opened the muffler on my 3years old 260 and it has a thick layer of carb built up. does that mean that my carb setting is to rich?  I have to lean the L or H screw?  Thanks

[Al_Smith]

It would be the H .However as I recently learned the 026 and I assume the 260 had three different muffler system .One was for a more quite operation and is highly restrictive .

[PNWRusty]

I opened the muffler on my 3years old 260 and it has a thick layer of carb built up. does that mean that my carb setting is to rich?  I have to lean the L or H screw?  Thanks

Both circuits need to be adjusted separately (they might both be too rich). I assume you run a 50:1 fuel/oil mix. Do you use a quality synthetic oil?

[teakwood]

Thanks for the answers.

It's the new style muffler, they have nothing inside but just two very small sloths where the fumes can escape, i have a older 260 with the older style muffler and i have opened her up and she runs a lot better since than, less restricted. I think i will open the new muffler up as well.
I will adjust the carbsettings but i felt the saw was running normal and strong. I am not the best at carb adjusting but i hear when a saw doesn't run right.

Yes i run 50:1 mix and i use exclusively stihl oil. Although i have changed from the normal red stihl oil to the blue sintetic oil 6 month ago.   

[teakwood]

I cleaned the muffler and opened her up. The saw works alot better now, will see if the carb still build up as bad. i also adjusted the carburetor a little richer as i the engine breath a lot easier with the mod muffler.
I also opened up the new (12hours on it) 361 and of course you feel the difference immediately. The sound is deeper and she revs up alot faster. I richend the H screw a little bit.
 
There is a slight problem after opening up the mufflers:  when i walk to the next tree i carry the saw around in idle, just for 5-10 seconds, and when i try to rev up the saw again sometimes she dies and needs two pulls to get her started again. makes like a big deep sound, like a hole, like when you try to get a big deep breath, and then starves.
does anyone know how to adjust that flaw?   

[HolmenTree]

Sounds like you have a lean condition bog off idle.
Try opening (richen)the L screw out a 1/4 turn and screw in the idle screw to speed up the idle a bit .
Check the H setting screw at WOT to make sure it's not too lean.