Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

hard cold start- bowl empty- passed leak test

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gclark:
My '72 Chevy truck has a Qjet 7042210 on it that I rebuilt using recipe #1.  After it sits for a few days, it takes probably 30-45 seconds of cranking before it will fire.  If it only sits overnight, it will fire immediately. 

I pulled the top off after several days of sitting, and the bowl was empty.  I had tested it for leaks during the rebuild using the soapy water pressure test described in Cliff's book. 

Just to be sure, I took the carb back off the engine and tested it again for leaks.  Still did not find any leaks.

Has anyone else experienced a similar problem?  Any suggestions?

Cliff Ruggles:
That seems pretty fast to evaporate that much fuel away?

I've left mine sit for a week, and it's pretty low but enough fuel in the bowl to start the engine.

It also seems like a long time to prime.  The fuel pump should fill it much faster than 45 seconds, or one would think so?

I'm wondering if it's not loosing prime and draining back to the tanks some?.....Cliff

gclark:
Cliff,

Thanks for the reply. 

I overstated the cranking.  It is not a continuous 45 second crank, more like crank for 5 seconds, release, crank for 5 more seconds, release, etc.

What would cause it to lose prime and drain back to the tank?

Geoff

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