ORIGINAL: Liberator
I have had this happen twice. I go to use my starter and the spinner and prop break loose and had I not stopped them they would have spun right off the hub. Luckily, the motor didnt start. Now both times the nut was very tight, but I had to cut the spinner a bit to allow the prop blade to sit nicely in place. "Composite props both times" I assume that I simply didn't relieve enough material and that the prop must have been touching the spinner a little bit, would that be a correct assumption?
Tom
Sounds more like a flooded two stroke or a backfire in a four stroke rather than a spinner problem.