I have a 16' Misty River aluminum fishing boat. I currently have a 40 mariner that is about to be trashed. I found a used yamaha 4 stroke high thrust 50hp. Is the High gear ratio and prop measurements 14" in diameter and 11' in pitch too much?
That is a combination for a pontoon or work boat. On high-thrust motors, the gear ratio is chosen so that the engine can swing a prop with large blade area but less pitch since it is installed on a boat that is hard to push. the motor will work fine for you but you need to swap props to one with much more pitch. Probably in the 15P or even 17P range. You will seriously over-rev the engine with an 11P on that boat. You need a tach to sort this out.
