I just found out that I can order just the motor and leave the rest of the trolling motor unit alone. In other words, same pedal, same steering, same shaft. Just remove the actual electric motor and prop and replace with a higher thrust motor. In other words take my 12V 28lb thrust motor and make it a 45lb thrust by just removing the old electric motor and replacing it with a new one. Has anyone ever attempted this? I can get the new motor for 120 bucks shipped, where as a whole new unit will cost between 4 to 5 hundred. So there is definite economic benefit going this route, just don't know how hard it would be to do. Thoughts?

so in other words just replace this:

Check with this company. They are the experts:

 

http://www.jonestrollingmotor.com/

Guess I should also mention, mine is an OLD OMC, the lower unit has a set screw, and appears to thread onto the shaft.