I have a Stihl FC75 stick edger that is 6-7 years old. It has a fair amount of usage, but it has always performed flawlessly. I noticed that it did not seem to have as much power the last couple of times I used it. This power loss is from start to finish, not just when it gets hot. Well, I put a new blade on it and the lack of power became readily apparent. I got out the tach and checked the carb settings. It was running rich, so I reset it to 10,000 rpm unloaded. After trying it again, it was a little better, but still lacking power. So, I checked the compression. With my Snap On gauge, it read 105-110lbs. This seemed low. For comparison, I checked the compression of my Husqvarna 326LS and Tanaka pole saw. They were 135-150lbs. Then, I pulled the plug and muffler and looked at the piston/cylinder. They look pristine. No scratches or anything. I cleaned the spark plug and threads and the plug seats fine. I also checked the muffler screen and it is clean. So, I am at a loss. 1. What do you guys think is going on? Is this compression too low? 2. I can get a new piston and rings for it, but I don't see how the cylinder comes off. It does not appear to unbolt from the top, like on a chainsaw. It looks like the bolts thread from the bottom, but I can't see the heads.