I have found that usually when my idle is hanging it is because my lsn is too rich and my idle gap is to large. This causes the idle to hang until the rich lsn loads the engine up. I would try reducing your idle gap until the idle falls nicely and then lean the lsn. However, as mentioned above your lsn could be lean too... a properly set lsn should load up some if you let it idle for 20 seconds or so, so the engine will bog a little before it clears out with plenty of smoke. Hope this helps you.