QJet expertise needed

[Primered_69]

I swapped on a qjet that has been sitting for awhile since my last one went south on me. Before the truck always started right away.

However, when I try to start the truck now I have to pump and pump on the gas and try to start it numerous times before it gets enough fuel in the "bowl" and turns all the way over. I have never messed with carbs too much so I am at a loss of what I can adjust. Can anyone give me a quick checklist to work down.

Once it is started it runs pretty smoothly. I adjusted the two screws on front until it idles fine.

additionally, I updated to a blazer tank and a new fuel pump.

I am good with my hands I just have no experience with these carbs and I want to get it running by the North Texas Board meet.

[pjmoreland]

Most of the problems I've had with Quadrajets have been caused by an out of adjustment choke. When the engine is cold, and you tap the gas pedal before starting the engine, the choke should close just about all the way. Once the engine starts, the vacuum produced by the running engine should actuate the little vacuum diaphragm attached to the choke, and the choke should open part way, since the choke only needs to be closed all the way while the engine is being cranked over. As the engine warms up, the bimetallic coil will heat up and open the choke the rest of the way.

1) Check to make sure the choke is closed the proper amount when the engine is cold and off. If it isn't, the rod connected to the bimetallic coil can be kinked, or straightened as needed.

2) Once the engine starts, make sure the choke opens part way the proper amount. If it opens too far, the engine will die right after starting. If it doesn't open enough, the engine will run rough. Tweak the rod that connects the vacuum diaphragm to the choke as needed.

3) Once the engine is warmed up, the choke should be open all the way. If it isn't, the bimetallic coil might be bad, or the rod connecting it to the choke might be out of adjustment.

Take a look at an operation manual for the exact measurements for these adjustments.

Since your engine just has a hard time starting, and then runs fine after it is warmed up, that makes me suspect the choke.

[Blue_71]

sounds like the "welch plugs" are leaking. they are a small freeze plug type thing on the bottem of the carb body, which are notorious for leaking. they are very small, but when you shut the truck off all the gas leaks out, you come to start it, the gas that leaked out has dried up, you have to refill the bowl, just like as if you had ran out of gas in your tank

most common way to fix them is to epoxy over them, with something like JB weld

[ckhd]

I'd have to agree with Blue_71.

I had the same problem with my 'burb, epoxied the plugs and it made a world of difference.