I have a 1754 Triton aluminum boat with a Mercury 40 4S tiller……first time on the water with this boat today and I was getting 28-29mph on gps at wot....does this sound about right? I assumed I would be around 35…..the boat was completely empty except for me (230 lbs), 1 battery, and approx 3 gallons in the fuel tank. I plan on installing a tach to ensure im getting max rpm