possible spun or loose prop

went out and warmed up throttled up then it revd up some and caught again, I've been adjusting the tilt to get it the best spot it is manual and thought i had it according to my last 2 trips buddy with me said it was cavitation so I stopped and dropped it 1 hole and seemed all good got to spot fished and went to leave and started to do it again i found myself going slower without the spin so I was going to put my new prop on this morn and when i went to loosen the prop nut it really wasn't that tight so i broke out the book and torqued to 90lb should i try it or just go ahead and put the new one on and get the new hub.
Thanks Robert


also where can I get a new rubber hub it's stamped 10 3/8X13 MWI

p.s. info on signature