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