2000 Merc 25hp/4 stroke-gear oil everywhere?

[trollin4trout]

Everything below the seal around the top motor cover is covered with gear oil. I've removed the lower unit and there doesn't seem to be any oil around the impeller housing- I haven't removed the impeller yet, but it doesn't look oily inside the outlet tube. Could there be a seal leaking below that allows gear oil into the impeller? I don't see how or where the oil is getting out of the bottom and being able to cover everyplace with oil up to the cover seal. Can you offer any ideas?

Thanks, Jim

[Boat Doc']

Best thing to do is pressure test it to see where it's leaking. It may be engine oil from a leaking powerhead base gasket.

[trollin4trout]

It's not losing any engine oil and this is clearly heavy gear oil. In addition when I drained the lower unit there was less than half a cup that came out.