Warped air horn on the Q-jet

[BADAZ chevy guy]

Got final inspection this morning. Ya for me!!!
Then I discovered a new problem. The air horn on the Q-jet is warped. Secondaries will open, but then they get stuck open and flood the engine. I pulled it apart. There's a good 1/8" warp in it. PO or someone who he had working on the carb didn't know what they were doing.

 

[chengny]

You didn't ask for advice/help, but someone else might do a search in the future and find this helpful:


Cracked or Warped Air Horn

Results in: Fuel leaking around air horn gasket, poor idle, ineffective idle mixture screws, erratic idle, fuel discharging out main discharge nozzles at idle, hesitations & stumbles, poor throttle response.

Comments: Very common on older Q-Jets: The two forward carb hold-down bolts have been tightened so tight that the entire top of the carb is warped or cracked. Once this happens, the airhorn no longer seals properly to the float bowl of the carb. This causes leaks in the idle transfer fuel circuit between the airhorn and the bowl, effectively eliminating the entire idle circuit in the carb. It also causes the gasket to be ineffective in sealing the rest of the airhorn to the bowl, resulting in fuel leakage around the top of the carb.

Remedy: No fix for this – buy a new carb.

 

[SlickGTP]

I have a few extra Q-Jets that I have for parts only, so if you need a new airhorn, there's a chance I'd have one you could use. Just need pics of yours that I can compare to mine.

 

[BADAZ chevy guy]

After closer examination, I discovered that it wasn't a warp that was keeping the secondaries open. There's a plug in the air horn casting (on the drivers side) in line with the secondary shaft. It was pushed in to far and was binding on the end of the secondary shaft. I drift punch and a light tap on the other end of the shaft were enough to nudge the plug out a bit. Now it all works fine.

 

[SlickGTP]

Very cool! Glad you were able to fix it.