---

Yamaha 70's aren't the strongest rated 70's, so 45mph might be a little optimistic. I would think it would be in the 43-44mph range with a light load.

It seems like you the right set up engine height & prop. In your picture it seems like you have a fin on the cavitation plate. Have you tried removing that? (or is even still on) Are you running with 1 person or more? Are you in fresh water or saltwater?

The trolling motor in the front is probably why isn't handling great with the motor 4 holes up. When I have 2 people in my boat it makes a difference in speed and how much I have to trim the motor with the person sitting on the front seat vs sitting on the rear seat with me. It could also trimming a slight bit of mph off the top end.

My boat definitely is faster than 34mph before trimming. It did 33mph with a 60hp motor and mounted in the bottom holes (motor all the way day) If you have the fin on the motor, that may explain the problem.