Where the through-hull is located:
1: Close the through-hull
2: Remove the hoses from the pump. There will be water.
3. If curiosity so leads you, remove the impeller cover. 6 brass screws.
4: Identify 4 bolts holding the pump to the engine.
5. Do what it takes to remove them. I had to use a couple different kinds of pliers to get at them all.
6. It will probably still stick to the engine a little. Give it a little bonk and it should fall off.
7. Bob's your uncle.