What is this leaking from my lower unit?

[l008com]

I unwrapped my boat today for the first time all year. The first thing I did was change the lower unit oil. I drained the old stuff out and put some brand new stuff in. I barely used the boat the last few years so the oil that came out was super clean. I filled up the new stuff and I'm on my way.

Then when I'm trying to start the engine, I notice something is dripping out. There's a little hole that I guess is some kind of vent hole? Except it's well below the water line so seems like that vent would become a water inlet? What is leaking out? Whatever is leaking out is filthy! Is there some OTHER kind of fluid/oil in the lower unit besides the primary gear oil?







What do you think?

The motor is a 1989 Mercury 90HP 3-cylinder outboard.
For all it's flaws and age, with a new battery and a full tank of gas, it did start right up I didn't make it to the water yet though. Soon, hopefully.

 

[Chris1956]

Smell the stuff. If it stinks like eggs, it is gear oil and not normal. If it smells like oil or gasoline, it is 2 cycle oil and normal.

 

[jimmbo]

Smell the stuff. If it stinks like eggs, it is gear oil and not normal. If it smells like oil or gasoline, it is 2 cycle oil and normal.

Rotten Eggs.

 

[l008com]

Smell the stuff. If it stinks like eggs, it is gear oil and not normal. If it smells like oil or gasoline, it is 2 cycle oil and normal.

Unfortunately I did not give it a whiff before I put the boat away.

But why would 2 cycle oil be coming out of a hole in the lower unit?

And if it's gear oil, how is it coming out dirty when I just put it in clean 10 minutes earlier? Not only that but the 'dirty' oil I removed wasn't even dirty either since it had so few hours on it. Yet the stuff coming out of this hole is way dirtier than all that.

 

[racerone]

It is a drain hole for a cavity.----Prevents freezing / cracking.------Normal for a 2 stroke to leak some oil there.------I have said it many times.------The mixing of gas and oil and operation of a 2 stroke is not well understood.

 

[airshot]

Oil in the fuel causes the exhaust to contain a black residue, anything that is part of or connected to the exhaust will have that black residue. That hole may be a drain opening for the leg exhaust, thus the black crud

 

[jimmbo]

Even Gear Oil can pick up Contaminates that it comes into contact with. Use you Nose to give you an Idea, or better yet, do, or get someone to do, a Vacuum-Pressure Test on the gearcase