Thanks for the hints, guys.
The only below waterline, thru-hull opening in the whole boat is the outdrive. The previous owner SWEARS that he never had this happen to him.
I'll take your advice and start from scratch -- clean it out and methodically try to find where the water is coming from.
Is it possible that this could be trapped rain water? We've had LOTS of rain up here, and the boat has been uncovered, exposed to much of it. She lives on the tailer, and I keep the plug out while she's on the trailer, but could it be that rain is getting trapped under the cockpit and not reaching the bilge pump until the boat gets to a launch ramp and gets tilted severely to the rear.
Wishful thinking, I know -- It's just that a seal around the outdrive sounds SO expensive!
I'll let you know what happens.
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