how do i tell if a carb is loading up at idle?

[Logan]

Ive only ever messed with zeniths, tillisons, and webers. Some of you know ive got a more modern holley carb im going to try out, but some of you say it will run to rich at idle. My question is other than being able to smell it running to rich, how am i going to be able to tell if it is dumping to much gas at idle? what are the symptoms?

 

[pat in Santa Cruz]

the engine will lope when idle is too rich. If its really rich, it will smoke black. The plug insulators will be sooty.