Well... got the boat home and finally got the owner enthused enough to spend a day actually working and cleaning on it. While looking it over, I see that the block is cracked freeze plug to freeze plug on both sides (300 ci Buick), and my first thought was Oh Poopy, gonna have to swap this out. Next thing I noticed was a fiberglass patch in front of one of the freeze plugs, with it closing over the hole for the freeze plug.
That got me thinking... this drive doesn't need a closed system to keep the water inside at at a specific level. In my understanding, the water source is the body we are floating on, it goes in, cools the engine, then goes out. Hmmmm....
What do you all think about tearing it down to make sure the only damage is to the outside of the block, then welding the block (Been welding my entire life so I think I can stop the spread and stabilize the block without any problem, I've done it on a street motor), and if that's ok, running the engine in it now?
If it was to be a car motor, I wouldn't worry too much, I'd either swap it out and update it, or pull it, weld the cracks and put it back in when I was satisfied with the repair.
I'd just like you all's input since I know so little about what I'm going to run into if I try doing that. Please remember we're talking about a 26 YO guy, making just over minimum wage, 2 kids, and trying to fulfill a dream of a project with his son, so it isn't feasible to grab a crate engine and dump it in there. I'm just involved because I love him, and offering technical advice, tools, and maybe some sweat to help him do it all himself.