Gear case drain screw washer failure?? milky gear case oil?

[GlenRasmussen]

gear case drain screw washer failure?? milky gear case oil?


I have a 2001 90HP 4stroke, the last 3-4 years, I have noticed at season end, there is always milky gear case oil, no water, just milky oil. I have changed the drain screw washers regularly, but does not seem to stem the problem? Just went to local outboard store, and they did not have Merc washers in stock?? closest dealer in miles away. Can I use a small amount of gasket sealer or 3m lock-tight, rubber O rung? as a replacement??

I last changed the Water pump 8-9 years ago, so seals else place in the system may have a small leak??
Please advise. thanks in advance.

 

[jimmbo]

The screw gaskets may be bad, but so could others. Get the gear case pressure/vacuum tested. That should pinpoint the leak. Milky oil is a oil-water emulsion, over a period of months the two will separate.
iboats sells the screw gaskets

 

[racerone]

Do you run the motor just before draining the oil ?

 

[Chigwalla]

If there's residue from the old gasket, the new one can sit cockeyed and not seal.
Pressure test the gearcase.

And the water pump is long overdue.

 

[Andy1804]

As above

 

[tommarvin]

Glen,you need to replace the water pump impeller every year.
You need to replace the lower unit gear at the end of every season, order your washers/seals/ parts online, no excuses.Don't put gasket sealer, Loctite get new seals every year.
You need to do a pressure /vacuum test on the lower unit after you get the new seals/washers to find the leak.
It could be leaking through the drive shaft seal or prop shaft seal.