I have a 1999 Merc 150 outboard.  I noticed I had a little stream of water leaking where the lower unit joins the upper part of the motor, so I pulled the cover and noted a little bit of water coming from the lower part of the engine (I really can't tell from where), collecting in the bottom part of the upper unit and then running out into the lake where the upper unit and lower units join.  I seem to have good water pressure according to my gauge and a good stream from the pee hole.  Anyone have any ideas where the water might be coming from (maybe water pump seal?), and as long as I keep getting good water pressure/flow can I wait until this winter to get it fixed?  Your thoughts/help would be appreciated.

Speculation only.  The first thing I would do is to drain the lower unit to see how much water you have in that area.  If you have more than a couple of tablespoons of water in the oil, then it's time to break out the check-book.

I have a 1999 Merc 150 outboard.  I noticed I had a little stream of water leaking where the lower unit joins the upper part of the motor, so I pulled the cover and noted a little bit of water coming from the lower part of the engine (I really can't tell from where), collecting in the bottom part of the upper unit and then running out into the lake where the upper unit and lower units join.  I seem to have good water pressure according to my gauge and a good stream from the pee hole.  Anyone have any ideas where the water might be coming from (maybe water pump seal?), and as long as I keep getting good water pressure/flow can I wait until this winter to get it fixed?  Your thoughts/help would be appreciated.

I had this same thing happen to me on my '85 mariner. There is a gasket between the block and the lower unit. You need to fix it now or you risk losing the block. When it happened to me the block was loose and wobbling and stripped out one of the mounting holes. The marina as to do a helical insert.