Hello I have a 17.5 blazer it is a 1988 model had a 150 mercury xr4 boat will run 72mph then it starts to loose control took the 150 0ff put a 1989 mercury 225 the boat will run 70mph with lots of petal left but the boat starts to loose control played with jackplate from top to bottom have a quicksilver 25p on now had a 27p chopper same results is 70mph all this boat will go even with more power? only rides smoth at 65mph.any help?
How much pos. trim? Might need to trim down a little. I have a 18prov with a 150+ yamaha, 10in. jack plate, and it gets a little scary at 65 to 70. I have to run light to get 70 so it gets up out of the water pretty high and i have to trim down a little . But from my experence short boat+big power = hard to drive on top end.The longer the easier to drive.