Thank you Evil for backing me up on this

My advice is factual ,My boat has the current problem.

mg503 is the winner finnally an intelligent answer on this site.

I guess I am only somewhat intelligent?

That happened to a friend of mine and it was the heat exchanger...........

It's the grommet if it happens over the winter. Count me in, as only my port does this. Filled it up last spring and no problem for the season. I haven't noted if it's run out this winter. I'll have to look the next time I'm over in the building.

I filled the coolant back to fill line on Fri and it all ran back out over the weekend. It was 65-75 degrees this weekend, so I thought it might seal up. I think I found the gromet on the left if you're facing the front of the motor. What's the trick in removing the heat exchanger and does it just sit down into the rubber grommet without loosening or tightening anything? This small little stuff like this sucks.

This post is an insult to myself and everyone else who has taken the time and energy to attempt to help other members with problems.

Ed, I can certainly relate to your frustration. I try to help as much as possible on this site, but you always seem to have some smart a$$ come along and think their cute. I still need a little help with my problem and any advice would sure be appreciated...

Anybody else have this happen and what did you do to fix it?

Mercury Marine had some problems with the grommets under the heat exchanger on the 496's developing leaks after sitting and use. I believe they had a recall through the Mercury dealers to repair them with new grommets. Check with your local Mercury Marine dealer or your boat builder. Hope this helps.
Ray @ Raylar