# Yamaha 15hp 4 Stroke -- Water in Motor Oil



## Hsteele (Sep 5, 2013)

I have a 2005 Yamaha 4 stroke 15 hp outboard that recently started getting water in the motor oil.

The motor was acting up the last time that I ran it, so I decided it was time for some routine maintenance. The lower unit oil was perfectly golden, but the motor oil definitely had water in it.

When I hook up the water hose to the backflush nozzle on the motor and cover the pee hole, water drains out of the motor oil drain hole. I also ran a compression test on each cylinder, and both cylinders put out 30psi (at normal cranking/starting throttle).

Anyone have a similar issue in the past or have any advice on what's causing the problem? The two shops that I've called said it could be a number of things, but I wanted to check here first.


Thanks,

Harrison


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## noeettica (Sep 23, 2007)

Sounds like a blown head gasket 

That motor is very durable so that should not have Not happened ...


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## DuckNut (Apr 3, 2009)

I agree with Noe

But 30 psi seems way low. Most are around 100. I am no expert by any stretch of ones imagination.


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