Still trying to determine what parameter to change on a F150 Yamaha 25" shaft mounted on a '93 201 Mako. While up on plane at 4300 RPM and 30 mph the anti cavitation plate is under water. The water level while on plane is at the bottom fin of the lower unit extension which is about 2 inches above the anti-cavitation plate. I'm turning 5500 rpm and just under 40 mph at WOT with one person on board and it drops to 4300 rpm with 2 people. Should the anti-cavitation plate be that far under water on plane? The engine is mounted in the #2 of 4 holes from the top hole. The engine is about 6 weeks old and has 16 hours on it. I'm about to take it in for the post break in service and I believe my dealer would entertain the idea of raising the motor at no cost if I can come up with a convincing argument. I'm trying to avoid buying a $450 prop 15" pitch if it is not necessary. Some of the feedback I've received is that the 15" pitch is not recommended for the F150. Where I live in the Florida Keys I don't have the option of trying out a 15" prop as a loaner. I would be forced to buy it and live with the results. What is the consensus?
