I'm in the middle of bolting my carb back on my truck and replacing all the vacuum lines, and there's this "jet" on the vacuum lines that goes to the choke breaker on the carb, you can see it in the middle of the picture here:



Anyhow, here's an up close pic of it:



Can anyone tell me what the proper name for this thing is, what function it serves, how to test it, etc? There's no markings on it beside the serial number "6J23" stamped on one side, I have no idea if it's directional, or how to test it. It's probably the original one from 27 years ago, but if I was going to replace it, I wouldn't even know what to ask the auto shop for.

I've blown/ sucked on either side of it, no air gets through it (though I know engine vacuum is higher than any vacuum I could physically pull on it). I'm going to toss it in there for now, but if someone could fill me in on its purpose, it would be much appreciated.

 

FSM states the "jet" is for the CB(Choke Breaker) system. This system slightly opens the choke valve to prevent a too rich mixture after firing when the choke is closed.

Looking at the diagram the jet appears to be like a large resonator or more like a vacuum damper if that makes sense..? It does not appear to be a check valve and the FSM states no specific direction of installation. It does provide a test for it and the CB subsystem.

"Disconnect the vacuum hose between the jet and the vacuum pipe."
"Apply vacuum to the jet and check that the choke valve slightly opens.

Hope this helps.

 

Yes, thank you very much. I'll have to borrow a hand pump to pull a vacuum on it... At least now I know what to check for

 

Just to add, I believe it serves to reduce the strength of the vacuum to that diaphragm, which is what Kioshu is stating.

 

I recently got a 1987 toyota 4x4 pickup with a 22r and a Weber carburetor. I am debating on what to do with the air bypass system: block or fix. I'd rather fix it but it stops at the ASV and the resonator is missing. Questions: what does the resonator do? Does the resonator just go to the ASV? How do I test the ASV? On top of the ASV, is that a vacuum line and where is supposed to go? The charcoal canister in the bottom left of the picture: would the large hose on that go to the resonator? Thanks!