81 Evinrude lower unit leak?

Ok so I finally got this beast running. Evinrude 115hp E115TLCIM. I guess it sat for a few years, but new gas, plugs, oiled cylinders, and a good cleaning of the carbs had it running with one turn of the key! (once i figured out how they rewired the controls....sheesh!)

My question is the bottom end, when hooked up to the muffs it leaks some water at the seam where the lower unit meets the exhaust housing. I've checked all the parts lists and there is no gasket listed for this location.... is this ok? a picture of the leak is attached. Water pump seems fine, but I'll likely change the impellers before any real use.

Before I water test it I want to change the gear oil as well. Does anyone have a guide for this, preferably with pics but ok if not.... first boat an I'm still learning the terms.... the motor was easy, not too different from a bike...

Re: 81 Evinrude lower unit leak?

Not uncommon to have some leakage at that seam, when you drop the power unit to change the impeller make sure and scrape the contact area and make sure it is clean, might slow/eliminate the leak.
To change the lower oil remove the lower slotted screw (drain) and then the upper slotted screw (vent) let the lower unit drain and then fill the lower unit from the BOTTOM screw until it comes out the top screw. If you install the top screw first it will let you install the lower screw without loosing to much oil. Make sure to replace the plastic washers on both screws.