Mercruiser I/O vs Outboard SeaCraft?

[NoBones]

I could be wrong but the pyhi/deck plate has to do with the livewell?

Your not wrong Don..
My 20 has the plate in the same place.
I put a strainer plate on the outside and a sealed one
on the inside of the live well. The original was drilled
holes through the glass skin. It looked hokie with the holes, hence the 4 inch strainer plate.

See ya, Ken