Why does my weedeater run balls-to-the-walls wide open but will not idle or run at other speeds?

stop changing your mix you'll burn the motor running it to lean on of the side of the carb cover theres a black rubber grommet it will have two small holes one has a H one has a L these are your high/low adjustment screws they are set with your machine running sounds like the H is fine so( in) is faster (out) is slower your high should be adjusted by a pro as it takes a few back and forth turns to achieve rev, torque and duration while the low is for icle purposes only go back to your original mix tho that is critical your welcome (in advance)

When I read your question, I laughed. Your weed-eater reminds me of my Siberian Husky when SHE takes ME for a walk.

BUT, I have never had a gas trimmer. I have a WORKS battery trimmer which works great for me.

Throttle stuck? Linkage? Dirt someplace? You'll figure it out.