750 Eddy Carb issues

Metering rod carburetors are sensitive to vacuum signal. What camshaft are you running? Metering rods and large camshafts do not get along well at idle. The low vacuum signal causes the metering rods to jump around at idle and will cause an erratic idle situation. Can you give us some more details? Camshaft size, where your initial timing is and any other details will help.