milky lube

I was winterizing my boat today, and when I drained my gear case lube it had a milky appearance. What is the cause of this and how can I fix it? I have a 92 120 Johnson.
thanks

Re: milky lube

Milky looking lub is an indiction of water intrusion. There are many places water can get in including the prop shaft seal, oil fill and drain plug seals/gaskets, drive shaft seal, and the carrier seal. But before you panic, check the fill and drain plugs to see if the gaskets (or o-rings) are present. If not, there is a good chance the water got in through either of both of those. Fill with lower unit lub and install the plugs with new seals. Next season, after the engine is run a few times, check the lub again. If it's milky again, you need to have the lower unit re-sealed.

Re: milky lube

The gaskets for the drain and vent screw are often over looked and are the number 1 spot for a water intusion. I hope you replaced them when you serviced the lu?? Remember the water will sit at the bottom of the gearcase, so when you check the oil, the water will come out first, so keep a close eye on the first bit that exits. Full synthetic lu oil will also help. If a water intrusion is still present, do a pressure test as Silvertip stated as follows.

To pressure/vacuum test a lower unit:

a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required