Fuel Evaporation or leakage from the carburetor

[Merc Cruzer]

I recently removed the blocking plates from the heat risers, so now the carburetor is noticeably warmer. Would this account for the loss of fuel in the float bowl over a two day period of not starting the car?

Or would it potentially leak down through the jets or power valve?

The first picture is of the correct float and fuel levels. The second picture is after the car has sat for two days. The third picture is of a float bowl with the jets and power valve (the possible sources of leakage).

Just as a further test, I have refilled the float bowl, on the cold engine, to the correct level, with the backup electric fuel pump, I installed years ago (when I first learned about vapor lock), and will check again tomorrow for any fuel loss. The garage stays at around 50 degrees, so ambient temp should not be an issue.