2005 Mercury 90-HP Water in Oil

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Fire93Medic
Posts: 3
Joined: Sat Mar 10, 2018 6:59 pm

2005 Mercury 90-HP Water in Oil

Postby Fire93Medic » Sun Apr 22, 2018 5:44 pm

I posted about problems with this 2005 Mercury 90-HP engine earlier. The problem I will soon describe below seems worse than earlier problems.

Last fall (2017) I picked up a boat with a 2005 Mercuty 90-HP FOURSTROKE engine; it looked like new and ran great. The lubticating oil on the dipstick looked clean.

When the crankcase oil was drained a good amount of water came out first. I found an old post on this exact situation that described a problem with a gasket on top of the water tube gone bad causing the water to enter the oil sump; I am guessing this engine has the same defect.

For anyone familiar with this and the process to access this gasket: Does the powerhead need to be removed?

Or, is the gasket accessible in an easier way.?

With fishing season near I do not like the idea of pulling the powerhead if I do not need to—seems like a better winter project. Below is the link to the original post. I tried a search and did not find anything else.

Any help would be great.

Thanks—Andrew

http://continuouswave.com/ubb/Forum3/HTML/020030.html