Just tuning in..............

Looks like you are geting lots of info...good stuff....

I didn't see it mentioned before so I will share my experience with a ST .51 ringed...

Ran fine w/o any probs when level....
But point the nose up and errrp..... it would lean out and quit...
I even tried a perry pump....It would still lean out and quit.... no matter how rich.......
I tried everything......tanks, fuel line, differend sizes of fuel tubing (med, large, small) nothing made any difference....
I even placed ne ring, piston ect, from a dif engine (new stuff though) and made no difference.....

I Recieved a new ST .51 and no issues........................... ran great even when nose up....

Moral of this story.............
Sometimes you will never figure it out..