Im just guessing, but is it possible that since the engine is new and hasnt been broken in, it just needs more time. This season I started running an 55AX. The first 10 flights I kept getting dead sticks(I would keep the plane close and high expecting it to quit just in case). I didnt change anything, got some fuel through it , and now the thing just wont quit.

Again Im just guessing. If whats been stated above checks out ok....What I personally would do is run say 4 or 5 tanks on the ground to break it in more then make sure your tuning is right. Try again and see what happens. Thats just what I would probably do. I would also use a tach to make sure your tuning it correctly. For some reason I cant tune my 55ax perfectly by ear. I use a tach every time and havent had a problem since the first week.