I have a 6210 holley, Yesterday was the first time I started it up, since October. It idled fine for about 20 minutes. I shut it off and when I restarted it, it was idling badly, Very low and belching black smoke. I figured it was a fluke, and put it back in the garage. This morning I went to take it for a ride, and it was doing the same thing, I pulled the aircleaner and I had fuel spitting from the secondary boosters. Any Ideas?

sounds like the secondary float is stuck.

Well the wife took it to work any way, and when she got home it was running fine. She said after about 20 miles it smoothed out. I will pull the bowl and check for dirt in it.

Make sure you pull the needle and seat out of the bowl too, and check those. Sounds like there was a bit of crud propping it open that eventually passed thru, but there may be more. Might behoove you to check the primary side too, transfer pipe, inlet, and filter.

Good plan, Thanks