Hey all. I have a Mark 75 but the gearcase is cracked pretty badly. The previous owner said a little epoxy puddy would fix it. What are your thoughts? I'm going to replace it but it would be nice to salvage it so I'd have another on hand if needed. I'm on my phone right now but here are some pictures.
That's a very typical problem, the cavity in the fwd end of the lower unit is supposed to have a drain hole at the bottom; the hole gets plugged with debris/corrosion products, then the "trash" builds up and eventually breaks out the housing. Or it sits with water/trash/etc, freezes, and busts it out.
Far as I can recall that's not an oil-containing area, so you should be able to effectively weld-repair the crack.
Be sure to clean all the gunk out of the cavity, and restore the drain hole, so it doesn't happen again.
The responses you receive are correct, but if you want an unmolested gear case,... (a complete lower unit),...I have several short shaft units I'd sell.
If it is a long shaft I don't have one.
Feel free to PM me if I can assist you.