Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Venturi's in action in idle

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Marx3:
Hi first post ever!

I have recently rebuild a 7043202 carb, though I usually buy Hygrade's kits ( actually rebuild several Qjets ), this time I bought a cheaper one from Echlin.
It is supposed to service a handful of carbs with different cast-numbers.

The problem is that in idle, the engine sucks fuel out of the venturi's. It is not dripping, the fuel is flowing out of them. very weird.
the carb has holes drilled in the plates, but still I have to open up the plates alot to get it too idle.
Tried the carb on a Buick Nailhead, and at 600 rpm it the venturi's where flowing fuel.

I am 99 % sure that I selected the right airhorn gasket and gasket for the baseplate. ( there was 3 different in the kit ) 

What am I overlooking here? or do I simply just try another gasket?

Regards Jacob

Marx3:
forgot to mention that, though floatlevel was set to specs, I tried lowering it a bit.
I also tried blinding the holes in the plates.
No effect. Venturis still distributing fuel in idle

Cliff Ruggles:
Do you have one of our books yet?  It covers complete/correct rebuilding, and custom tuning, etc.

That carburetor has an idle bypass air system, which is more effective than drilling the throttle plates to lower the angle at idle speed.

I would imagine the idle tubes are plugged up some, or not large enough for the application.

Viton parts are manditory these days.  We sell Viton high flow needle/seat assemblies and complete accellerator pump assemblies.  Aftermarket kits will not contain the correct components as the supplier of parts for these kits is still using up old stock.....Cliff

Marx3:
I have just bought your book, it is on it's way across the sea!

I have rebuild 10-15 Qjets in the past, and have never seen this before, but on the other hand, have never used Echlins cheap kits.
I will try cleaning it out again!
Can you explain to me exactly what is happening that makes the fuel flow form the venturies?

And if that does not work, I will buy a Hygrade kit, they come pretty cheap here in Europe. I ain't quite ready to spend 80 bugs and have it flown overseas, tax etc. just yet. Not on this carb at least. I dont mean to sound cheap, I think I will use your kits in the future!
thanks for the reply!
Regards Jacob

Cliff Ruggles:
Unfortunately, you will find that all of the currently available over the counter kits will not contain good parts.  All of the companies who made and sold carburetor kits have went out of business, or have been bought out by one major company.

We buy carburetor kits from various sources periodically to check out the contents.  They will NOT contain Viton parts in most cases, and not even the correct parts.  They will also not contain a lot of parts that we consider manditory items to replace during rebuilding, such as the secondary plastic cam/spring, Viton high flow needle/seat assemblies, power piston spring, upgraded accellerator pump with new springs, etc.

Are incomplete kits with inferior parts in them really a bargain?.....Cliff

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