Finally figured out what was causing the engine in my Plymouth to run so rich especially at idle. The PO of the vehicle purchased a rebuilt carb for it and when I opened it up discovered the pump return spring was missing. So far I've called about half a dozen carb shops around the country looking for one with no success.

I've modified the spring out of a Holley 600 and installed it. It now idles much better (without all that black smoke) but I can't take it out on the road right now to give it a proper test. I'm a little concerned that too heavy or too light spring could have some detrimental effect on the carb itself. Since I've never seen the correct spring could someone who has one do some measurements and post them?

I would like to know the following:

Diameter of the wire
height of the spring
number of coils
base diameter
top diameter

Many thanks in advance.