Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Quadrajet 7029282

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Kavesh:
Hello all

My carb has been working well for while now and then at the worst possible time decides to get sick, at my daughters matric dance (prom).
At the drop of point a gave the motor a couple of revs, nothing hectic and the motor stalled. After a couple of attempts to restart she started but the idle was now very erratic.
Managed to drive her home, while driving she was fine no issues, but when stopped at the lights the idle was not good.
Next day started up and was smoking a lot, black smoke and engine very shaky, tried gentle revs and it did not clear so shut the motor off and stripped the carb.

See pic of what a mess I found.  fuel in the baseplate.
I originally thought it is the well plugs, but I am not so sure now. I have previously epoxied these and the epoxy is rock hard. (I sealed these just as a precaution before).
Could a stuck open needle and seat have caused this issue?

Would appreciate any advice on this please,
Thanks

Kenth:
This maybe?

Kavesh:
Thanks for the reply. I did not have the little clip on the needle.

Cliff Ruggles:
The carburetor will NOT care for function purposes whether you have the clip on the needle or not.  There are hundreds of carburetor designs out there that don't even use them.

What the clip does for the Q-jet is to lift the needle off the seat as the fuel evaporates away and prevents the soft tip from sticking or getting "glued" into the fuel inlet seat. 

I'm not saying here not to use the clip as being able to re-fill the fuel bowl after months of sitting is pretty important and I've seen a few cases where the carb sat so long that the needle actually got glued in hard enough the carb had to come apart to get it freed up.

I would mention however that if you use the little clip on the needle that it need to be "adjusted" properly or it isn't doing you any good right to start with.  The opening is too big and if you just push it straight on the needle it will not lift it when the float drops to the lowest position.  The opening that slips over the needle also needs to be pinched down some with a small pair of needle nose pliers or it will not fit well and can tilt sideways (causing flooding in extreme cases) in use and even slide off. 

I custom adjust every single one on all carbs built here and check to make sure it's actually lifting the needle off the seat like it's supposed to.  I suggest to anyone reading this to do the same.....

Kavesh:
Cliff, thank you!
I have put together a couple of carbs in my time and every time I used the little clip I would try and see what it does to the needle and every time I would tell myself it does not seem to make the needle move.
I would assume that perhaps its my bad eyes or it needs to be in operation to actually make the clip useful. This is the first time I have heard that the clip needs to be adjusted to function.

I have watched many videos and read many articles on rebuilding these carbs and never have I come across this little secret.

I would imagine it will be a delicate process to not damage or loose the clip, which I have done before :P

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