Ya'll may already know this, but thought i'd share anyhow. Bought an Echo chainsaw about 6-8 months back, CS 355 as I recall. Really happy with it till recently. Started fine, but just didn't have the punkin it used to. Stopped in at Kubota where I bought it for some lawn mower parts, and asked if they worked on them. Yes, but you needed to be careful you didn't spend more than it was worth. Told him what it was doing, He said look on your muffler. Should be a couple screws or bolts holding the vent on. Take them loose and under there is a screen used as a spark arrestor. They can get clogged with carbon and keep it from exhausting correctly, causing problems. Sure enough, all clogged up. Some carb cleaner, and it's back to running like a top. Thought maybe that's the problem with a Stihl doing the same thing. Sure enough. Cleaned it, now I'm chainsaw rich. Just in case anyone else has a similar problem.

Nice! I'll keep that in mind for my equipment

yep ... same thing happened to me.

Good info. Thanks for sharing with the OB.

That's why you TexAg, thanks!

I thought, damn, this sounds familiar. Walked out to the barn and performed an autopsy on my Stihl to find the man is right. Cleaned the screen, fired right up and runs great. Many thanks for the tip!

Glad it helped. Went through the whole owners manual after I discovered this. Nothing. Guess a person could probably toss it if he wanted. Sure it's EPA BS.

Seen videos where a feller has to burn it off with a bottle and wire brush it. Makes sense carb cleaner could work.

I've personally never had a problem with spark arrestors but they are a maintenance item, as you see. On my Stihls, I have removed all of the spark arrestors so as to tick one more thing off my box of "things that can be a pain in my ass at the wrong time". If you are into tuning your saws, you can port your exhaust a tad too while you're in there.

If you do take it off, keep it. They are required if you are working on federal land or in some cities.