Carter BBD confusion
??? That doesn't sound right. Where did you get this Carter?
You say "Funny thing i noticed about this carburetor is that the fuel pump diaphragm has a spring on the top and the bottom." I assume you're referring to the accelerator pump. I've had mine apart, it only has a spring at the top.
The throttle blades are closed on mine, the throttle return spring keeps it that way. Almost sounds like you got a carb someone's been messing with and got it installed backwards!
Here's some pics of mine on a 273, hope it helps.