Jay, take a VERY close look at the slots in those plugs. If they seem deeper
in the center than at the edges, they're supposed to be removed with
something called a DZUS driver. My Johnson outboard's drain plugs are like
this, and a normal screwdriver (which you can get at Sears, by the way) will
mess up the slots.

I don't think the plug is like what you have described if I remember
this correctly. I will double check it before I order the screwdriver
from Harbor Freight.

Thanks for the warning though.

Jay Chan