It looks like your upper drive oil seal is leaking. Water is getting into
the foot and pushing oil out into the drive boot and finally flowing out of
the vent hole through the transom into the bilge. Drop your drive to take a
look.

Recommend that you fix this quick, especially if you are in salt water.
Your U-joints are probably wet, gimbal bearing, all gears and bearings may
have started corrosion. If bad, bearings, gears, u-joints and drive shafts
may need changing. I got similar water damage on my upper gear housing,
changed practically everything except for the housing.

If you want to attempt this, you will need a few tools,
1. upper housing retainer wrench
2. Upper housing gear shimming tool, one for driven gear and one for input
gear
3. For the lower drive, similar tool for shimming the gears
4. Bearing carrier retainer wrench
5. a 150ft-lb torque wrench

Check out mercstuff.com, sterndrive.com on tools and write-up on the
subject.

Good luck.

TanPS

"D.B." wrote in message
...
I have a 1989 Stingray with a 3.0 liter Mercruiser engine with an
Alpha one outdrive. I have been getting about a half a cup of water
in the foot after about every 4 hours of operation. I have been
changing the foot oil after every use (4hours) so as to keep things
from going poop until I could put it in the shop. I recently changed
from the expensive Mercruiser outdrive lube (quicksilver) to a cheaper
80W90 gear oil (seeing as I was changing it after every 4 hours of
operation). I have been noticing what I thought was gear oil in the
bilge, but was not sure until I changed lubes. Now I am positive that
I have gear oil from the foot in the bilge. My question(s) are
these.... would it be that the upper water seals in the outdrive are
causing the water to get into the foot and the oil to leak into the
bilge? Question number two....I am a decent mechanic.....without
having specialized tools, is it practical for me to replace the seals
myself (I did rebuild a Porsche motor several years ago....to give
you a benchmark of my mechanical capabilities)

Any help would be appreciated.

Dave