Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

T/A dies when put into gear

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77cruiser:
If the vacuum is moving around that much 10-18 something else is wrong I suspect. Leaking valves or flat cam.

Jeffs68:
X2 Jim, if JZ has a shop, I'd suggest doing a cylinder contribution test. No sense in trying to dial in a carburetor on a mechanically faulty motor. If it does only have 1000 miles on it, but was built some time ago, I'd add a can of Seafoam to the crankcase and run it for 15-20 minutes varying the RPMs. Change the oil and filter and see what the vacuum is doing then. May have freed up the sticking valves.

JZ:
It took awhile, but I'm back on the T/A. The timing adjustment (18 degrees base) and relocating the vac line to the distributor to the port right of the fuel inlet worked to keep it running in gear although I think the 500 rpm it idles at is too low for this engine/carb setup. If I raise the idle in park to 950, I start to get nozzle drip but in gear the 650 it idles at is pretty good. However, I've noticed some other issues. The air horn gasket is appears to be saturated and there is fuel seeping up around the accelerator pump and leaking from the nozzles after shutdown The mixture screws are out nine turns, float level is at 13/32" while running (I have a gauge from OTC that fits into the hole behind the choke valve) and I pulled a vacuum on the needle and seat when I had it apart last time following Cliff's book and it held vacuum fine. The air horn is warped but I didn't think it was too bad because I tightened the air horn down without the gasket in it and put a bend-a-light down it and couldn't see any light showing through (to the outside anyway) so I  used a 1/16" thick gasket from Cliff's. Also, after this car sits for about a week, the float level has dropped to nothing (as per my gauge). The bottom plugs were sealed with J-B quick and since this is a '78 carb could this be a problem or am I loosing my fuel through the top somehow? And would any of this have anything to do with the nozzle drip I'm getting at the higher idle rpm?
To answer Cliff's question, I have no idea where the original carb is and neither does the current owner so I guess its a mystery of the universe.
Thanks again for your help!

JZ:
Sorry, I forgot something else I noticed. The power piston isn't pulled down at idle. The way I understand it, it should be so is this merely a problem with too heavy of a spring or does it have anything to do with the air horn being warped?
Thanks!

Cliff Ruggles:
Wrong spring, insufficient vacuum at idle, or the hole is blocked and not supplying vacuum to it.

JB Weld is USELESS for sealing up bottom plugs.  100 percent of the carbs that come in here with JB Weld dabbed over the plugs leaks right thru them.....Cliff

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