mercury bottom end oil

[beertech]

I have a 2006 mercury 9.9 4stroke outboard. Wondering is the mercury bottom end oil just 85w90 gear oil. I have a bunch of castrol stuff is why im asking

[sonny]

No it isn't,,,marine bottom end oil is made so that if water enters it will actually mix with the oil and help prolong damaging results from the water!