Wetting in 2n4 Carbs

I have overhauled my carbs completely and did a static balancing as described in manual.
When installed I have noticed that carbs are wetting on the air intake plenum from the bottom of small brass tube. Please see the photo.
Any suggestions for the remedy.
Wetting 2n4 carbs

I found the problem.
Intake Valves for 2&4 cylinders were not closing properly and pushing air back through the carburetor throat due to cam timing issue.