ALL WATER when draining lower unit on F100

I have a 1999 F100 4 stroke and just went to drain my lower unit for winterizing and what came out was pretty much ALL WATER. However, when last operated (at full speed for 20 minutes) four days ago, the motor and lower unit performed flawlessly and quietly.

To further complicate issues, two years ago I had a Yamaha 90 two stroke and the same exact thing happened, with the motor operating flawlessly immediately before draining the WATER from the lower unit.

What are the odds of this happening to one owner on two different motors two years apart?

Now I am assuming (having drained lower units on Mercs for years) that the stuff that should drain out of the Yamaha lower unit is NOT SUPPOSED TO BE WATER.

My questions are:

1. Why/how does the water get into the lower unit?
2. Where did the low unit grease/oil go to? (no signs of a leak)
3. And if there was a leak, why didn't the water leak out?
4. Is leaving the lower unit without any liquid in it outside over winter bad?
5. Anything wrong with re-filling it with proper lube and trying it out for a few weeks next spring?

Paul

[boats.net]

You have a bad seal, most common is fishing line behind prop and damaging prop shaft seal. It needs have seals(drive shaft, shift shaft and prop shaft seals) replaced, fresh oil and run for awhile then change oil again before putting into storage.