Dadwith4daughters I've never had that problem. Sounds like creosote build up. Can you describe your smoke emitting from the stack? Keep the thin blue smoke in mind and try for the invisible blue smoke that you can barely see against the background. When it comes to smoke more isn't better. Also when searing did you 'over do it'? You don't want the outside truely burned, mostly blackened. Might be that Okie will be in Monday to give his technical view of it.