About 6 months ago, I asked for advice on my Stihl trimmer that has been running like crap. Most of you suggested just replacing the carb and I pretty much agreed. Then I got lazy because summer came and I didn’t need it. Today, I noticed that it wouldn’t prime with the gas cap on and ran OK with the cap off. So I replaced the gas cap for $8 and now it is running like new. Vent lines must have gotten clogged up. I still plan to do a full carb/air filter/spark plug replacement before next summer, but I also needed to replace the worn out trimmer head today so we’ll see how it runs through fall and spring.