TOPIC: Impeller OOPS and why

Periodically we mention that it is important not to rotate the driveshaft (or flywheel) counter-clockwise once an impeller is installed to avoid impeller low water pressure issues.
So-o-o-o,...
I thought I would post a picture of what can result from such behavior.
I can not answer why the stupid impeller will flip its' blades the wrong way when counter-clock rotation is done - but not be able to simply flip back upon clockwise rotation, but here is proof that supports the fact that once committed, the blades will not return to their appropriate direction and lack of desired water pressure/delivery results.
doc
ps: if any of you are English grammar experts,...My last stentence probably got me an "F"

Question?
then why does merc tell you to rotate the flywheel backwards when using the timing tool on the old 4cyl motors. And what about the D-R motors that run backwards for reverse. Just want to know.

My theory is that it was hand turned at some point before long term storage and took a set just like a regular impeller would over long term storage. just a thought.
Dr if you get a chance call me 1 914 310 7086. Dave.