So I have a 2016 FX21, 250 SHO and a 25T-1 that is blue printed and balanced by Lainier Propeller. Since I bought the boat I have been running right around 9 dots on the jackplate, the boat would run around 69mph-70mph at 5800 rpm's max. Last year I started playing with engine height. So I started by raising the jack plate higher figuring I need higher rpm close 6K, got to 10 dots and only gained 50 Rpm's, holeshot suffered and gained no top end. So I started to lowering the jackplate back down, all said and done I am at 7.5 dots, 5700 rpm's and my speed is 72mph.
Load/weight was the same.
Here's what I don't understand why lowering the jack plate and lowering rpm's made my speed increase? It doesn't make sense, does it? Also I think I need to be around 6000 rpm's which I would think should gain me more speed.