I recently installed a Holley Avenger that had been rebuilt then sat in the box for about a year (bad, I know). It ran great when I first installed it but after a few weeks it was running poorly. I checked the float level and adjusted the mixture screws for highest vacume and idle. The problem now is the idle won't go below 875. I can adjust the idle speed screw, but the idle doesn't drop.

I pulled the carb and fuel is leaking from the front barrels. I replaced the power valve thinking this was the obvious culprit, but I have the same problem.

Anything I should look at, or do I need to do a complete rebuild?

 

Sounds like too high of a float level. Setting it can be a little tricky, are you using the site plugs to determine the level? You'll want fuel to slightly trickle out of the site plug with the engine running....