Beings the rpm came up and the boat slowed down I would say the prop is too high out of the water. 2.75 sounds pretty high, I would set it at 3.5 below the pad and try that. After you run it you can raise it .25 at a time till the boat starts to slow down.
2015 Nitro Z8 w/250 Pro XS
PB 10 lbs, 4oz at Alan Henry, 06/23/16. 11:30am.