John,
I was a YS newbie and did look at the plumbing directions, also had a dozen other people do the same and also try there hand at tuning, to no avail. And this group included several YS diehards.

This was a 140L, never did run more than 3 minutes before it suddenly lost the smoke, got hot and quit. I met another guy at the field with the exact same problem with a 110. I just laughed, wished him luck and walked away.

Funny how I've never had a problem tuning any other engine. I hate to bash YS, but they can take their pumps, regulators and whatever and do you know what with.