Repairing Wet Screw Holes In Transom

[2ndCurse]

I removed an old transducer from the transom of my '91 Wellcraft V-20. When I removed the screws, water ran out of the screw holes. It doesn't look like they were sealed at all. I drilled out the holes trying to find dry wood. So far, no dice. The transom still seems very solid and it's an old boat, so I really want to avoid a rebuild. What is the best and most cost effective solution? I can drill the holes out and fill w/ Marine-Tex. Fill w/ 5200? I've seen a product that soaks into rotted wood and hardens, seems half-baked, but maybe... Any Ideas