[Hi_Fi_Guy]

Also, did you increase the venturing size? With the work done on your engine it may be needed along with jetting.

Do some searching as there are some really helpful Zenith threads here. On one an owner did all sorts of Air/Fuel ratio testing and tuning on his Zeniths. REALLY helped me when I was considering venturi and jet selection. My Zeniths run 100% better than when I purchased my T.

As far as plugging the enrichment circuit did you use cap screws with locktite? I've seen people try rubber vacuum caps or even worse bolts shoved into rubber vacuum lines and these set-ups always seem to leak air and lead to intermittent carb issues.