As it is an I/O, I would guess the outdrive will lift
most if not all the way out of the water. If this is true, you will have no problem with water leakage, although, you will have to support the outdrive when you pull the engine. Most of the I/O units have a boot in the transom alowing the outdrive to move, but keeping the water out. These boots are a weak point, and can easily be damaged when pulling the engine.
I was able to change the boot on an OMC
outdrive I had in in a 26' cabin
cruiser, in the water, using 2 truck innertubes, and the bowline winched down hard on a cleat. Without knowing your exact situation, and boat, those are the best bits of info I can throw your way.