Hey Guys, I have a 24 foot Bentley pontoon and I just put on a 2004 Direct Injection 115 hp Evinrude and I am getting blow outs or slippage of some kind when I reach 3500 to 4000 rpms, I have a new prop which is 13.5 X 15, which was recommended and the old prop was the same, The motor height is...