my trimmer is just not running as efficiently as it has in the past. It feels as if it is at 75% power. I plan on checking the compression this week. My question is this: if I have to replace the piston and rings, how complicated of the job is that? I believe that I am better than average at mechanical understanding and have an average accessibility to tools. Will I need special tools and should I take this to a repair shop instead of attempting it myself?