This is true and those puppy`s shrink up quickly w/todays crap pump fuel. I just did a pair of carbs for a friends quads and the Honda was the worse w/black/brown resin like junk completely plugging the fuel inlet and all of the jets. Took forever to clean em out all because the fuel wasn't drained and they sat for months.....maybe a lesson for those of us who don't drive everyday or even weekly.

You might want to pour a cleaner into the tank a
couple times a year... when I did testing on this
for Chrysler I found that 1 product truly worked..
plenty had alcohol in them but did nothing.. the 1
product that Chrysler went with works... the dealers
sell it.. its not cheap but well worth it... Chrysler
put its own name on it but it was made by Chemtron..
when I was testing it we had a issue of the fuel in the
south west having a lot of sulfur in it and was plugging
up the injectors.. I had thousands of warranty injectors
to test on... I would get a as is base flow then use the
cleaner(I tested over 40 different products) then re-flowed
to see what the improvement percentage was... this 1 product
was leaps above all the rest.. I could get 98% of the flow
back on the injectors.... it also works with carbs.. I know
this on my own junk

What`s it called Mike.........I heard Stabil works well but never tried it myself.......

Mopar Injector Cleaner... in small lettering it says
Chemtron on the can(at the bottom)
EDIT
Stabil is a fuel stabilizer and not a cleaner

Cool thankxx..........I know Stabil is a stabilizer and if more guys put it in their suv`s and cars when sitting for months, they wouldn`t have these problems. I will get that cleaner though and try it in my ultrasonic cleaner for the super dirty carbs........

The accelerator pump seems to be working ok, 2 nice streams of fuel when I check it and it doesn't appear to be leaking. You say the one you worked on had a "worn pump well" ?? I'm not familiar with that. Could that cause flooding after running for a while? Would a rebuild kit fix it?

The worn pump well lets fuel seep by the rubber plunger after the carb warms up, as I understand it. I tried everything I could think of to make that carb work, float settings lower, fuel pressure down to 3 1/2 psi, new accelerator pump parts. Nothing worked. A Holley does now though.
It is hard to prove that that is the problem for absolute certain, but I had some thoughts on possible repairs. Maybe just a hone with a real fine stone and polish it?

If the ID is worn enough that the rubber pump doesnt
have enough interference and lets fuel by it...MAYBE
a piece of thin wall tubing pressed in to give a smooth
wall and a smaller ID... I've never tried it ... if you
can find the right size tube... I havent used one of those
carbs for years now

Start with the basics. Assuming it has solid lifters, check the valve lash. If the valve lash is too tight it can cause problems such as this once the motor warms up. If that's not it, rig up a fuel pressure gauge that you can observe while driving and see what the fuel pressure situation is when the problem occurs.
If the fuel pressure is OK, I would bypass the ignition switch to make sure that you don't have an intermittent open circuit there. I just drove my Hemi GTX 2600+ miles on Drag Week, and it does not have Holly's and I had no issues. You don't need Hollies, you need to find the problem.
Good luck

Thanks to all for the suggestions. Hemi-Joel, it has hydraulic lifters. How would I go about hooking up a fuel pressure gauge that I could read while driving? Everything is stock so it doesn't have a fuel pressure regulator.

I wouldn`t run any car w/out a regulator and visible gauge so you can at least keep an eye on things. I`d rig up a regulator and gauge for starters and go from there.......

I wouldnt bother with the regulator yet... T in a
fitting at the carb with a line going to a good
gauge... see what it says when your problem happens
then make a change IF needed
EDIT
T in the gauge between the mech pump and the carb..
the rubber hose will be easier

You can get some fittings and a small gauge to plumb in between the carb and pump to check at idle, then wing it and see how high it goes.

Get a vacuum gauge/fuel pressure gauge like this:
http://www.ebay.com/itm/VINTAGE-engine-c...=item25adbf6767

T it into the fuel line by the carb. Tape it to the outside of the windshield where you can see it, but it can't leak into the cockpit. Drive till the problem occurs, then see it the fuel pressure is excessively low or high.

Also, for a different test, hook the gauge to manifold vacuum, and see what it does when the problem occurs. it should be fairly steady, not jumping around. Also, if you can get your hands on an air/fuel ratio meter, like an LM1, you can see it it goes rich or lean when the problem occurs.