I have a 1964 Merc650. I'm trying to remove the lower unit. I've removed the 5 "obvious" bolts holding it on but I can't seperat the lower unit from the rest of the outboard. I've beat on it with a rubber mallet but it still doesn't come off. I would beat on it harder, but I don't want to break anything. I would be willing to beat on it harder if I knew that I was doing it right. Any help would be appreciated.<br />