Here's an accessory for your Carb that adds a weighted flapper to the intake like several after market Carbs have built in.

What help would that be? Wouldn't it just give you a richer mixture?

I don't get it. What's it supposed to do ??
George n L.A.

A self closing valve apparently.

Garnet

Well, I can see where it would prevent a big backfire through the carburator, perhaps blowing the intake manifold off instead. Other than that, I can't see any advantage. Seeing all the new ones in the box makes me think that it was not a popular item.

Neil

If it's a "Case Valve" as stated on the box, could it be the crankcase that it is referring to? If so then maybe, just maybe, it goes in the oil filler and prevents oil blowing out the filler when the cap falls off. It might automatically open when you pour oil on it and the close again when you have finished pouring, like plastic rubbish bin lids. Just a guess.

Isn't there a flapper, something like this in the Stromberg carburetor?

The pin is off center so it wouldn't close completely. What it appears to do is shut at idle and open at faster speeds. This is almost the equivalent of a Idle Air Control sensor. The weight would be on the bottom and would want to keep the valve closed. It looks like the only thing it could do is slow the air entering the intake so it has more time to heat up. I don't see how this could have helped all the much, but I could be wrong. It kind of reminds me of the "snorkel" found on breathers made through the 70's where the flapper would stay closed until the engine vacuum pulled it open, this made the carb only pull the hot air from the stove pipe rather than the cold air from outside.