Yanmar SD20 Oil - emulsion?

[Halo]

Over winter I changed the gear oil in my SD20. No idea what was already in there so I used Castrol EP80/90 as recommended in the handbook.
Did about 180 miles 2 weekends ago (some motorsailing) and noticed that the oil was looking like egg yolk. Not clear and emulsified. The level was about the same.
Yesterday I changed the gear oil again. Not sure if the problem was incompatibility between old and new oil or a dreaded water leak. Any thoughts or similar experiences from the forum?

 

[Sans Bateau]

I'd put my money on water ingress, sorry.

 

[wizard]

Its water entering via a damaged seal/shaft- two options

1. just strip out the lower shaft assembly and change the oils seals, Yanmar have a workshop manual for the sd20 to guide you

2 If you find the shaft is grooved where the seals sit on the shaft, the next option is to fit speedi-sleeves over the grooved part of the shaft

Just had a further thought, this problem appeared after you changed the oil, did you replace the drain plug O-ring when you changed the oil?

 

[david_bagshaw]

Over winter I changed the gear oil in my SD20. No idea what was already in there so I used Castrol EP80/90 as recommended in the handbook.
Did about 180 miles 2 weekends ago (some motorsailing) and noticed that the oil was looking like egg yolk. Not clear and emulsified. The level was about the same.
Yesterday I changed the gear oil again. Not sure if the problem was incompatibility between old and new oil or a dreaded water leak. Any thoughts or similar experiences from the forum?

did you check soon after stopping, if so, might it be beaten in air bubbles?

emulsfied oil usually increases the volume as well. just thinking on the bright side.


ep & water deffo increases in volume, well did in an outboard lower leg I delt with.