How To Check Carb

I have a 89 B2200. I know it aint no race truck but, Seems like it is running on 1 barrel. How do you see if the second barrel of the carb is indeed opening. Just depressing the throttle does not do it. Seems like it is hooked up to a vacuum diafram.

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I thought I had the same problem so I checked mine too.
Parked up with the air filter off you should be able to operate the throttle off the side of the carby and once you reach high enough in the revs you should see the secondarys geting pulled open by the vacuum.
I just gave it a few quick good revs and could see it open quite easily.