I have a recently new to me Hydrasports 185E with a 175 Johnson faststrike. Over the boat is great. Idles good on the water, planes out fine and overall runs great. The problem is I am only getting 49 to 50 mph at WOT. Rpms are roughly 4800 to 4900. I checked the prop and it has a 25 pitch Renegade. Is this the right size? I do not have a jack plate by the way. And the motor/pad distance is 2 1/2 below pad.