I was trying to get my old echo srm210 string trimmer running.This trimmer has two issues. One is it will run great for about 15 minutes, but once it gets good and warm it won't want to restart. The other is that it doesn't make any power. I bought a new trimmer and stopped using it. So far I've replaced the carburetor and fuel lines/fuel filter and cleaned the clogged spark arrestor clean. If I remember right, I couldn't get the muffler off to check the exhaust port on the engine block. That was a while back. I want to say the no restart when hot started after it sat unused for about 2 years.