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On Fri, 07 Aug 2009 15:18:10 GMT, "Mike Slater"
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"Mike Slater" wrote in message
news:4rIem.816064$yE1.657711@attbi_s21...
I have a Mercury 3-cyl, 60hp two-stroke. In the bottom of the engine
cowling, just aft of center, is a one-way water drain valve with a little
plastic ball at the bottom of a tube that allows water to drain out of
the
cowling but not get sucked in due to the negative pressure created from
the
carburetor intake. Funny thing is, there are two more "open" holes at
the
back of the lower cowling with no one-way valves present. With all the
salt spray I see splashing up on the bottom of the cowling when I am
running, I am sure sal****er must be getting sucked in the two back
cowling
holes because my three sparkplugs are rusted. Should I plug those two
holes? They appear to be factory drilled openings.

Mike
Guys... I need advice on this one. Should I plug those two back holes?

No, if they weren't supposed to be there they wouldn't be.

My Merc dealer says I should drill them even larger to a 1/2" diameter.
It's complicated because the way my motor is trimmed up slightly, the water
runs toward the front of the motor lower cowling housing. I agree now that
plugging is not the answer. I used silicone as a test and then the water
had no where to escape. He said with Mercury's the water gets in through
the gasket where the top and bottom half where cowling cover meets the base.
Remember, this is a pontoon boat. I told him I was going to add a water
deflector to eithr side of the transom mounting so that water cant even get
sprayed up near the motor cover. He said that was one way to handle it.