Carburetor question-comparing two different Carbs (1 Viewer)

[devo]

The first is an Asian USA carb. The question is, what is the function of these air/vacuum passages? Circled in red you can see that they pass through the boosters/nozzles to the exterior of the air horn. (The nozzle assembly has been removed)

The second is an Asian general market carb Circled in blue. It does not have the air/vacuum ports?

Also on the general market carb the primary booster nozzle has a hole in it. Is this Toyota or did someone drill it?

Thanks and any input is for my educational enrichment!

 

[John Smith]

That is from the factory and not PO modified. The ports are for emissions hookups that many markets outside the USA did not need. Hence, why your Non-USA carb does not have the ports. Also the date code on Aisin carbs is Year Month Date. So your first carb was made 1973 November 23, the second, 1972 August 26th.

 

[peesalot]

noticable difference in the jet next to accl pump.