ORIGINAL: Nathan King
I'm not sure what you are getting at with tightening, but I can help with your question. There is no prop position that keeps the starter from loosening the spinner, however there is a prop position that lessens the chance of breaking a prop on a deadstick and makes it easier to hand prop. When looking at the front of the airplane turn the engine crank counterclockwise until you hit compression. Now tighten your prop so that it sits horizontally.
Dang, Nathan King, you seem to know something about almost anything. That's a good tip! Problem is with a newb like me, I have no idea of when I hit compression. Would that be when you feel the beginning of resistance, a half turn after, etc. I really don't know.
Also, why would an engine stop at this point if it stopped running? I'm guessing the same reason - resistance at that point.
By the way, how long you been at this?