So...I am having a very similar issue. She hasn't run in a while and was running very rich when shut down. I wonder if it is one of the above issues. I need to investigate some. I am going to try the oil 1st. As long as you are careful and don't really push on a bind...I can feel my way.
How do I do I set it all back up in the end...after rotating crank and cams. It is just ...line up all the timing marks again? Or is it more in depth. I usually just swap belts out...I have never broken one or had any issue like this.