Something like that happened to me with a new Irvine 53...couldn't get it to start all that crap 2 hours later I take the head off and low and behold I had put the sleeve in the block wrong (can't remember why I removed it) so anyway' the motor wasn't getting enough air...after that it ran like the freaking wind until one day I pealed the dago red it was on like a banana through a tree on the east side of our field after looking down for just a sec to trim (find the trim) throttle I looked back up and my baby was gone...I saw it for a flash just before it came through the tree...my only crash in four years of flying...and yes I fly more than just circle's...I guess I'm just better than most of you guys...just kidding