Just bought a '93 Nitro 170 with a 115 Merc. Came with jack plate and
with small porpoise fins or whatever they are called. The boat pulls
very hard right coming out of the hole; trimmed under. Flat out
running about 50 at 5200rpm it pulls slightly left. I know I can
adjust the trim tab but feel it would have a bigger impact at full
speed. Would be scared to get too much pull at top speed as it feels
like it is skimming a little bit as is. Should I lose the porpoise
fins? Does it sound like the jack plate needs adjusting up? or down?