Hi, new here and in-between boats right now, but if I can offer a little advice, I owned a HEAVY TRI, 18' with the 898 (198 HP) Merc in it and found out at the time , the only difference between the 198HP and the 228HP was a 4 brl carb and different intake. Switched mine over and performed better but the RPM rose a little high. Talked to an old prop guy (Rebuilding service) and instead of increasing pitch, he rolled a little more cup into the trailing edge of the blades. I picked up about 3 mph with only a 150 drop in RPM. Worked great. Something you might try.
