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Originally Posted by taseal  always good to do a mag check! I can't believe how some people actually don't even know what that is! 
and also irritates me when they move the prop in the wrong direction! that poor vacuum pump! |
The reason that people move the prop in the wrong direction, is so that the engine won't start if there is a broken p-lead on one of the mags. It is the only safe way to move a prop.
I woulden't worry about the vacuum pumps. It is true that you will kill a pump very quickly if you mount the incorrect pump for the engines direction of rotation, but rotating the prop by hand won't hurt anything. When I was at FSI the props on everything with a two bladed prop was moved everytime the airplane was fueled and there were never any problems with vacuum pump failure. Many other flight schools do the same thing. You can bet that no one would do this if it led to premature pump failure as this would cost them quite a bit of money.