[MPDano]

The Air Box is what has the Air Filter in it, correct? If so, it doesn't matter whether it's on or off as far as how it runs. Was it constant black smoke? How long did you let it run? When you say it ran good, did it sound like it was missing? Any engine noise (ticking, clanking)? I believe black smoke is burning oil. That could be rings? Probably Russ can confirm this as he had bad rings in his Euro. Maybe post video on Youtube and post the link.