I think you need to go to a PowerTech 4 blade stern lifting prop and also raise the motor a notch or 2. I would want the cavitation plate about and an inch or 1 1/2 inche above the "V" on the stern. With the sharp "V", it kind of rules out rule of being even with the cavitation plate. I had a similiar problem with my 23WA and w/FrFrank's advice made the switch and it made all the difference in the world. I have a Merc 4 blade sitting on the shelf for a right hand twist w/Honda hub kit, but Mercury says it is a bow lifiting prop, so that would not be the answer, just the opposite effect. I went from a 14X17 3 blade to a 15 1/4 X 16, 4 blade. check at
www.ptprop.com