Quadrajet Problem Solving > Diagnose a Quadrajet carburetor problem

Rebuilt Qjet won't start or stay running

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tayto:
Rebuilt a 1980 Pontaic Firebird 301 Q-jet #14080272 with one of Cliff's kits this fall, but didn't get a chance to attempt a start up until this weekend. I manually sucked fuel up to the carb with a hand held vac pump and poured fuel down the bowl vent multiple times to get it to run. It would start but would only stay running if I pour a constant supply of fuel down the throttle body. The car ran when the carb was originally pulled a year ago so I think timing should be "close enough". I didn't think to verify to see if the pump was actually pumping before the battery died however. We replaced the carb and carb spacer gasket that is specific to the 301. We ditched the EGR valve as it was non-functioning plus the fact the local parts supplier wanted $150 for a new one. I made a block off plate out of 3/8" steel and put on a fresh gasket. Replaced all the vacuum lines, omitting some circuits for devices that were no longer installed in the car. Also replaced the grommets in the valve covers, as well as the PCV valve and its' grommet. This carb was pretty warped upon initial removal. I made my own plates and straightened the air horn and main body as best I could. I used Cliff's thicker airhorn gasket and once everything was screwed down and torque to spec it seemed to fit really well together. I have the carb pulled already so I will have to inspect the impressions on the gasket to make sure everything is sealing OK... I set float to 21/64" as per factory literature. I'm thinking when I have it open again I might set it to 1/4"? I also ditched the spring on the seat. I'm thinking maybe  the needle and seat could be damaged? If I vac tested it, how long should it hold a vacuum for, and is it alright if it drops during that time provided it doesn't drop to zero? Or should it hold 15 in-hg steady for 10 minutes if that is what I apply to it? Well plugs were tested with compressed air and soapy water, no bubbles. When carb was installed in the fall no fuel was left in it, so I don't think it has any varnish in it. I also cleaned it with an ultrasonic cleaner, small diameter steel wire and lots of carb cleaner, the thing was spotless.

Any ideas on where to start?

429bbf:
don't laugh or get mad . but id start simple . gas in tank, any fuel coming to the carb from the fuel line , plugged filter.once them are confirmed . then id take the carb back off . fwiw

tayto:
After I charged the battery I confirmed the fuel pump does indeed pump. Didn't have a gauge but it seemed to have a very powerful stream. I bent up a new hardline, needs to be test fitted though. I took the air horn off the carb, no debris in the bowl (good). I also checked the float... calls for .328" but it was set closer to .400"!! Would this cause a no idle condition, ie: flooding?

tayto:
Sorry, with the float set lower it wouldn't cause flooding but a LACK of fuel delivery, correct?

blazer74:
If your sure you have fuel supply to the carb and no restriction at the inlet filter. If you have the black check valve backwards in the filter that could be a problem if  you have one installed.
Even though all the kits I've gotten from Cliff didn't have one in the filter.

If you removed the needle spring and let the carb sit for a while the needle could be stuck. One of the purposes of the spring is to allow the float to pull the needle up to allow fuel in.

just a thought. Good luck.

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