Solex 40 P-11 missing part question?
 

I have a set of Solex 40 P11-4 carbs I'm cleaning for an early 912, and noticed a part missing. The part appears to be some sort of jet vent tube that is in the air flow of the throat of the carb. The part looks as if it's simply pressed into the carb top. I looked into the head/cylinders on the one side with a boroscope, and didn't find the part, or any evidence that it went into the engine. Anyone know the technical name of the part, and where I might be able to find one? Thanks!
https://www.thesamba.com/vw/gallery/pix/1762307.jpg

It is called a "diffuser". They are pressed in. Take a closer look to see if it slid out or was snapped off. It's possible someone tried to remove it during a rebuild and broke it off, or succeeded in removing it and it was too loose to stay put. If it came loose and fell thru the carburetor while driving, It's possible it was knocked around in the cylinder and was blown out thru the exhaust. I cannot find the separate replacement part. You may have to source one with a complete cover from used parts. Perhaps you could replicate one with brass tube from a hobby shop? I'm not sure what tuning issues it would pose if simply leaving it out.

Used cover on ebay, no affiliation:

https://www.ebay.com/itm/Porsche-356-912-Solex-Carburetor-Top-Lid-Cover/253151862348?hash=item3af106de4c:g:t2UAAOSwY0hZuXR S

Here's a cheaper one in the UK if you can talk him into shipping to the US:

https://www.ebay.co.uk/itm/SOLEX-PII-40-CARB-TOP-PORSCHE-356-912/253509395655?hash=item3b065664c7:g:Z8kAAOSwVWFasks n

donco, thank you so much for the info, and taking the time to search out some sources for a replacement. I was worried that there wasn't a simple replacement since I had not found any listings on anyone's parts diagram. I was able to find another "parts" carb that was about 90% complete with a good top I was going to switch with. I do have a use for the completed parts carb, so I will be looking into your eBay listings for just a top section. I have seen accelerator pump jets off of Solex VW carbs get injested, and I did not see any markings, or damage anything like that in either cylinders on the side with the carb missing the diffuser. Thanks again!