Stihl trimmer

I have an older Stihl trimmer model # FS 72 When it did run, it would not idle. I had to keep it wound up some. It did start easily though. I was using it a couple weeks ago, again keeping it wound up pretty good, and suddenly it died, and hasn't started since. I did replace spark plug, and checked spark arrestor. I have a spark tester that I put inline with spark plug and it seems to have good fire, at least to the plug anyway. That's about all I know how to do. This is a 2 cycle. I had Stihl fuel in it at the time. (that stuff aint cheap) It does have compression, and when I pull the plug, it's always wet, so I believe it is getting fuel. I hesitate to take it to the shop because of it's age. Probably not worth it. Any ideas on what to check next?