Next time your saw starts to loose power check the spark arrestor. If there is a lot of soot on it take it off and put a torch to it. Propane torch is fine. Don't ruin it just burn the crap off. If that is the problem it should run fine. 10+ years on my husky and sthil and thats all I have really done to them except for a plug once in a while. Harbor Saw in Hoquiam taught me that little trick several years ago. I was looking at a new one and they told me to take it home and try this. If did not work they would look at it. Well I never had to take back.