Too much string there. The string should wind up less than halfway up the top. If there is more string than that, it will not flip over the full 180°. If the string is too short, the top will flip over more than 180°. String length can affect the throw greatly.
Try just a few wraps less, and try an over-hand throw - by that I mean hold the top up by your head, palm away from you, tip pointing left (assuming you are right handed) and just push it out away from you and let the string do the work.
Lemme know if that does not work. I wish i could get my hands on it, I could size the perfect string for it in seven minutes.