I have a Echo Trimmer that I bought last year that has been giving me problems. It wouldn't start so I have done and checked everything that I know. I rebuilt the carb and I can get it started at full throttle but I can't get it to idle at all. Anything below full throttle dies. Pretty much as soon as I let go of the throttle it dies. I have tried playing with the screw a little bit but no luck. Any ideas? Thanks!