Any Weber guys here?

[PercentSevenC]

Originally Posted by craig3x

can't seem to find what you are talking about. can you refer to this schematic and let me know what you're talking about? Also, how important are the air horns? (number 58 on the schematic)
http://webernorthamerica.com/pdffiles/48IDA.pdf

"Pump exhaust valve", number 11 in the diagram. Its purpose is to bleed off some of the accelerator pump shot. A "zero" bypass jet indicates that it has no bypass hole in the side.

The air horns smooth the airflow into the carb, increasing power. They come in different sizes so you can fine-tune the length of your intake system.

Also, are you sure you have 47mm main venturis in a 48 IDA? That doesn't even seem possible, and certainly not recommended.

[craig3x]

Originally Posted by PercentSevenC

"Pump exhaust valve", number 11 in the diagram. Its purpose is to bleed off some of the accelerator pump shot. A "zero" bypass jet indicates that it has no bypass hole in the side.

The air horns smooth the airflow into the carb, increasing power. They come in different sizes so you can fine-tune the length of your intake system.

Also, are you sure you have 47mm main venturis in a 48 IDA? That doesn't even seem possible, and certainly not recommended.

you're right. I did not measure the venturi correctly. I measured at the bottom. When I measured that narrowest part, it measured 42mm, which I understand is still big. But venturi size should not affect a rich or lean condition.