What did I break ?

[ilpufxit]

Sounds like what happened to me when I bought my 8ight. It had been overheated. I could smell the hot electronics smell on the esc, the motor did the same things you're describing. I sent the motor out for service and I was told that it had become de-magnetized from the heat. It was cheaper to buy a new motor. Problem is, the esc may also be damaged. If you have access to another BL motor, I would plug it in and try the esc that way. At least if you have to send it out, you can do it right away. I've had really good experience with S&T (Quark) service.

No one said it would be cheap to play.