I would say you are just wasting your time messing with the carburetor, these things are made to be disposable, your time and aggravation are worth something, not to mention the cost of the carb kit (or worse yet, a new carb). I'm not familiar with the TB trimmers, but if it's anything like the Ryobi's I've seen, the rod is a 2 piece stamped steel POS that literally beats the engine up from the inside out! I would guess the crank seals are shot if it has any time on it at all. I see you already purchased a new trimmer, I would cut the losses now, carry the old trimmer out with the trash and never look back; chances are the sting line bump head (even if it is in any kind of shape), won't fit a decent trimmer either.