I recently had
I recently had a brand new, maybe 10 hours on it, Yanmar impeller spin the center hub. It looked perfect the first time I checked it. If this is the case, replace it with a Johnson brand impeller. Easy to spot, as the Johnson has a screw which goes all the way through the impeller, not just the pin. Apparently this is not a real unusual happening, so from now on I will only have the Johnson impellers on my boat.
Dream like you will live forever. Live like you will die tomorrow. ( James Dean )