[Destroyer]

Like Spare and others have said, have it looked at. As far as the antiventelation plate goes, it's not pot metal, it's aluminum, and can easily be welded by any competent welder. But for my money, if you have a whole spare lower unit just sitting there I'd throw that on before I invested a cent in the broken one. Also, I'm a little worried about that water/oil you said came out of the lower unit. Did that come out when you drained the lower unit? If so it probably means you have a bad seal and will need to replace that also. And yes, you can pull the lower unit off with the prop attached or taken off, it doesn't really matter physically, but we're talking about an expensive part (the prop). Merc props are a snap to take off.. just bend the tab, unscrew the nut and slide it off. what could be simpler? It's amazing how much damage an unbalanced prop can do to an engine.... and how much power you can loose with a bent prop, so why take the chance? Always remove the prop when dropping the lower unit.

PS, it''s always better to post your pics here in the thread instead of in your profile... that way ppl can see instantly what you're talking about without the need to refer back and forth. Try and take several different views of what you're problem is.. There's a lot of sharp eyed people on this site and it's unreal how much they can see and correctly deduce from what looks like a normal picture. Makes life a lot simpler.