I have experienced the same thing on my 2001 classic with every prop Ive put on the ole Merc. I have the luxury of a hydraulic jack plate now and I can almost guarantee you that if you raise the motor a touch it will go away. My rig will do it when I drop the plate down really low for running rough water or a really heavy load and then forget to raise it when Im ready to skin her back. So, raise it up a little and try it. Do this in 1/4 inch increments until the issue stops. If you start getting alot of Tourque on the steering wheel and loosing lift then you have gone to high. Chris CoupelPaulina, La.Chris CoupelPaulina, La.