I am not sure if turning the air bypass screw out or in gives you more air to the carb?

The Haynes Weber manual states that when synchronising the throats on a single IDF carburator, the bypass screw locknuts should be loosened and the screws then gently screwed in to the seats. If the throats flow differently then the bypass screw for the one with less flow should be adjusted. I assume this means that the flow will increase as the bypass screw is screwed out.

On my dual 40 IDF's I had one carb that was balanced with both bypass srews seated and the other carb required one bypass screw to be adjusted.

opening them up allows more air to enter without going thru the butterflies. so opening them causes a leaner condition. tomlinson's book states that they should be no more than 1 1/2 turns off seated.

kevin