well, i put the plug back in and tightened it as tight as it would go. and still does not stop the draining of water. . what next?
Based on the photos you've provided it appears to me the seat portion of the petcock assembly is missing. The "wing nut" (movable) portion pictured threads into the seat portion (stationary). The seat portion is pictured in post #14, item in the left of the picture.
Your pictures of the movable item show signs of rust as if it has been threaded directly into the manifold and will never not leak becuase it is hollow and not seated. Brass does not corrode like that, only steel/iron oxidizes that way.
Quicksilver makes a quality petcock that will thread into a 1/4-18 threaded hole. This is a standard thread size commonly found in many marine exhaust manifolds/engine blocks. The removable portion is a 9/16" hex head which allows for a standard wrench to be used for removal.
FYI, post #7 mentions "nice and tight" for installing the movable portion. I disagree due to the nature of the petcock seat along with the need to remove the plug on a regular basis. Finger tight/snug is acceptable along with inspection to ensure its not leaking with the engine running
The petcock pictured in post #16 is by far the absolute worst style I've ever come across for this application. I remove and replace this style petcock with my aforementioned style whenever I come across one