Carb not squirting fuel after warmup

[59bluesilver]

Nice morning, went for a drive. After about 30 min., it started bucking from a stop light an died. Luckily I was able to coast to a filling station and filled up. Started and took off, got about 1/4 mile, bucked again and died. Checked the carb and saw the squirters weren't squirting fuel. I was about 3 miles from home. I let it sit for 5 min. or so, would start and go about a block where it would die again. Did that procedure over & over till I got home. On the last leg, it seemed to run fine, going about a mile where I finally reached home and shut it off. Yesterday went out for a drive again and the exact same thing happened.

New fuel sending unit with sock filter, new electric fuel pump with new in-line fuel filter, new fuel hoses and new carb filter.

What is the problem, it has to be inside the carb? I have a '69 4MV Quadrajet, 7029202

[motorvation2go]

First thing I would check is the carb inlet filter.
Assuming that proves clean and unobstructed, I'd next tee in a fuel pressure gauge near the carb inlet.
Plumb things safely (hose routing secure and leak proof).
Tape the gauge to the OUTSIDE of the windshield and watch what's happening with the fuel pressure while driving (locally!).   
If pressure is insufficient then maybe a dirty (rusty) fuel tank has messed up the new sock and inline filter?

Are any lines real close to hot exhaust system components? Vapour lock a possibility?

Was the carb cleaned and set up properly with good (Cliff's) parts?
If not the case (but pressure reads good before the carb during operation), maybe you have a leaking/sunk carb float.
Dirt in carb passages?
Hope this gives you a couple of first steps.
Good luck with the fix.

[59bluesilver]

Thanks for replying, I'll check out and do those things. What should the pressure be? I want to find the trouble and get it running. Then this winter I'll rebuild the carb right (I hope!).

[429bbf]

some where between 5 to 7 no more no less .while your rigging up your tee to check pressure id stick the end with the gauge in a bucket and turn on the key and check flow first.that would give you an idea like motorvation2go said if your sock has plugged again.remember pumps don't make pressure.they only move volume and the restriction causes pressure.fwiw

[motorvation2go]

Good point... good advice 429bbf! 
Yes check flow with the 'gauge' hose end open and discharging into the bucket.
Put out your cigarette for a minute or two.   

[59bluesilver]

I checked that, took the hose off the carb and put it in a coffee can. Flowed freely.

[motorvation2go]

OK...
Running (driving) observation is next.
Good stuff.
Interested to hear how things go.

[von]

That test with hose in the bucket may be misleading. My experience with a clogging fuel tank sock was that it would clog while driving, usually under load like going up a long hill. Then after the engine was shut off for a few minutes the debris that was clogging it would evidently fall off and the engine would run fine for a little while before the clog occurred again. IMO the pressure gauge test while driving is the way to go.

[429bbf]

good reply von i had a 53 ford that acted that way. ended up being a piece of electrical tape coming up on the stand pipe when it was under heavy load. ran great under light load fwiw

[Ethan1]

That test with hose in the bucket may be misleading.

 Agreed.

[59bluesilver]

After thinking about this and my situation, the clogging of the sock is the one that fits my problem best. When I recently installed the new sending unit I noticed the old unit didn't have one. I don't know if it rotted away over the years or never had one to begin with. I have hopes that this pressure test will confirm.

[59bluesilver]

Finally got around to draining the gas and removing the sending unit. Sock was not plugged, looked good. While the bottom of the tank had this black crusty material it wasn't getting into the gas, siphoned gas was clear. I blew out the line and replaced the filter. I have yet to do the pressure test. Does anyone think this still should be done or should I be looking at the carb?

[motorvation2go]

I can only speak for myself and respect that all choices are yours.
Logical sequence is a good thing though.

1. I'd have a clean tank to start with.
2. I'd still do the running pressure test... who knows, might(?) be a dud fuel pump.

If the pressure is good but the engine's starving it's [without question] time to get into the carb.

*Admittedly, you might (first) just pull the carb apart and find a mess in need of cleaning/rebuild.
Might fix everything... and maybe not!   
If you haven't checked the supply side first (running pressure test) it's a crap shoot.
Check the 'running' pressure first.   

[429bbf]

question what kind of rig is this . is this the original carb? you say you have a new electric fuel pump? are you  pulling or pushing through the old mechanical. i seen that cause lots of problems. fwiw.

[von]

The tricky thing about the sock is that it only clogs when the engine is running under load and the debris slowly falls off after the engine is shut off or idling. I'd remove the sock and install an in-line filter that's easily changed.