milky oil out of lower unit

[fishhead2005]

1989 35 hp mercury. didn't notice until boat was in water over a couple day period...when traveling home, milky looking oil started seeping from vent screw in lower unit. the filling and vent screws were tight, but didn't have the nylon washers, so I ordered 2 new ones. If the lower unit still leaks water after I put the nylon washers on, where should I look for the leak? Are there any common seals that leak on these lower units? Thanks in advance.

fishhead

[boats.net]

Could be prop shaft, drive shaft or shift shaft seals leaking, best to replace all of them.