I have a 2015 Margay with a 2015 Mercury 150 Pro XS on it and I am having the same issue, but mine is more when I have a partner with me that I have to trim the motor higher in order to get any type of speed (Yes, it kicks off a large rooster tail). But I am still only getting at most 41 mphs. I have had the boat for 3 years now and I tried to go with a prop with a higher pitch 26 fury, but the motor did not like that with more weight of my partner in the boat. When it was just me, the high pitch prop got me into the 60’s and the through the chime walk with ease. But I couldn’t even get on plane with a co-angler in the boat. I am a bigger guy so I am wondering if I need to raise the motor because of the heavier weight or do I need to lower the motor? Or do I need to get a 4 blade prop?
The Fury is great for speed, but doesn’t have as much lift in my experience with Merc 150 4-stroke on my Sabre FTD when loaded down. Tempest and Trophy are better as they have more blade surface area. Moving heavier items to the rear will help the bow fly as well, especially if you have heavier Minn Kota trolling motor up front. I wouldn’t raise the motor either as that will lessen the props bite and therefore create less lift, hope that helps.