I have an older Stihl chainsaw that I believe is a 028 Pro. It looks similar to the MS 280 C. It is about 14 years old and for the last 4 years or so, when cutting into wood, it just seems to lose power. I have rebuilt the carb countless times and have adjusted the idle screws as much as I know to do. I have also been told that it passes the redneck compression test (pick the saw up by the sarter cord, if it does not pull out, good compression). Any other ideas of what I could try? It is my backup saw, but I really like to use it because it is lighter that the Husky's.