What is this contamination in my fuel bowl? (pic)

[Michael]

Any idea what this might be?

While diagnosing a flooding problem I discovered that both fuel bowls had this dirt looking stuff in the bottom of the bowls.  The carb is only a couple months old (a professional rebuild that arrived appearing like new).  Every other part of the carb looks like new when I opened it so am lead to believe it was not there a couple months ago.  I have a glass fuel filter just prior to the carb and it is as clean as the day I installed it (long before the carb).  I am at a loss as to what it is or where it came from.   I wiped it out like microscopic dirt.   Any ideas?

Ps. The flooding was due to something (this substance?) on the tip of one of the float needles.

[Rapid Roy]

Welcome to the site

[Lss1six]

I would say it's from ethanol, it wrecks havoc on carburetors. We have a lot of small engines, atvs, etc that need the carb cleaned or rebuilt from time to time. I even put ethanol treatment in but it doesn't seem to matter. Could be rust in the tank/ lines as well.