Loud beeping sound under hood

If you pull that choke spring housing off, there are gaskets between it and the carb body that may be missing or squeeling from the air going by them.
Fire it up with that housing off and plug the port in the carb body and see if it still makes the noise.
If it does not when plugged at the carb body then cover that port with a peice of gasket material between the choke spring body and the carb.

At least now you know a trick to find stupid annoying noises. :-)