This might be easier. Look here:
https://www.facebook.com/marketplace/item/1348080029925359
YES, I have done what you describe.
Find an old bow-mount MK motor on Craigslist or FB for $25. Swap motors and done
For any but the smallest boats, you may need to buy a longer shaft. They are pretty cheap direct from Johnson outdoors, like $40 or so.
That being said, half the time, when I'm looking for cheap, local MK parts, the "parts" motor turns out to be just fine, needing a new battery terminal, switch or something else pretty simple. So you might just want to do a quick search for one and see what turns up.
Enduras hold their value, and if yours works well, you should get $100 or more, depending on the thrust and how clean it is.
Hope this helps