912ULS carb overflowing

"Nothing besides the intake air-hose attached to the carbs..............." 

A photo might be help.

Long shots-

What type of propeller is fitted?

Idle speed?

Shut down procedure?

Brief update:

It seemed to have been debris in the components in the engine compartment (most likely guess: the pre-installed fuel hoses).

After several long ground runs, we now see barely any debris in the carb float bowl (and those last ones now being very small) - after initially having several larger metal shards as well as fragments of the orange fuel hoses. (despite having flushed fuel through initially).

Charlie,

You would have to have quite a bit of contamination, holding the float inlet valve open, to have consistent overflows.

I won't be surprised if your back with this problem in the near future.😈

Hi Sean,

All you need to have constant overflows is a high wing fuel tank plane and the needle valve seat and needle valve not fully closing due to debris or the needle valve seat needing a good polish / cleaning. I just traveled to take care of this very issue. It could also be caused by someone tweaking the brass flat armature's when the took the bowl off or put it back on and failed to watch what they were doing.