Milky motor oil- '04 Yamaha 115TLRC

[Neil H]

I have discovered water in my oil.
What clues should I look for to find cause?
This is a sudden event.
Recent maintenance: Gear oil change, impeller change, motor oil and filter change.

[boats.net]

Run a compression test on engine(blown head gasket), look for oil leaks around drive shaft on bottom of engine(oil pump seal leaking)