....and win a big, stuffed animal, or something.

There's nothing I hate more than having about 20% of the information
necessary to figure out a problem, and being unable to GET more info due to
uncontrollable circumstances, *and* all the while worrying about the
situation. So, I thought I'd drag a few more people into this with me. :-)
In this case, I cannot hose-test my outboard until the $*%*) temperature
gets above freezing here, or I'll turn my driveway into a skating rink.

The motor's a 1996 Johnson 15hp 4 stroke. It's on a 14' Lund aluminum yacht.
Last season, I noticed some unusual spray near the waterline. It looked
identical to what happens when it collects a gob of weeds. But, it happened
when the motor was clean, and nothing's changed about the bottom of the
boat. I hose-checked it back in October, but only briefly due to time
constraints ("Dad....can we get a ride to the mall?"), and didn't have time
to take digital pics of the spray and where it was coming from on the motor.
However, I noticed no oily residue on the driveway, which seemed like
something to be happy about. Cooling water was flowing properly, too.

If water's coming out from where the front of the prop meets the housing, or
from one of the lower pivot points, what could be the possible causes? I
asking so I can spend a couple of nights with the service manual, imagining
horror stories, and deciding whether to even bother with the hose test &
just take the thing to the dealer (an expense I'd prefer to avoid).