Mike: When you get time it's interesting to read about and visually see how fuel pressure affects flow based on demand.
https://www.offshoreonly.com/forums/...me-vs-psi.html
Peruse these links.
https://www.google.com/search?q=how+...hrome&ie=UTF-8
https://www.youtube.com/watch?v=nAe_5YwWoV0
Also, since you now have your old carb to play with, go thru it piece by piece so as to fully check it out and practice rebuilding it yourself. I bet you will be successful unless the casting is porous as has been mentioned earlier.