Hi felllas, Lilly has really testing my ability to see eye to eye wit her, BTW she's a 74 F250 4X4 with a 390,I can run her in the shop and get up to operating temp and while that's happining I can watch the fuel in my fuel filter slowly emptying out then eventually she will spit and sputter cuz she has no fuel, then I can let her sit for a few hours go back out to the shop fire her up and do it all over again, things that I have done new fuel filter, new fuel pump all new rubber fuel line, and all new clamps, I have taken all of the steel fuel line out of the truck and pressure tested it with compressed air and put some bubble water on it and I have no leaks, I even took my carburetor lid off to see if the float needle was stuck in the closed position, no go on that, any suggestions, thoughts, tips, experience, knowledge would be very grateful, Thank you in advance. PS, I even took the phone in a motor off all the way to the timing chain to check the eccentric and that seems fine and dandy as well.

 

It sounds like you have been over everything except the tank and pickup itself. If there is crud in it, it can collect on the intake sock and block fuel flow. When it shuts off, the crud falls off the sock and it will run for a while.

I had a similar problem and it turned out to be a collapsing rubber line on the rear frame rail... since you have been over the lines that leaves the tank... or slight chance you have a bad (new) fuel pump.

 

I second the fuel pick up Idea , trash in the tank . Also try running it with the fuel cap off . You may have a non vented cap and need a vented cap .

 

I have put a new fuel pump on and the same issue still occurs, I have even swapped out my sending unit, and yes the tank is not Perty inside but I do have a cylindrical screen filter attached to the pick up tube, as of a month ago I had no such problems like this, also the fuel line is not near any major heat source (exhaust), I have taken the pick up sock off n she still does the same thing and iv even ran fuel line to a gas can next to the Lf wheel still the same

 

As a diagnostic, suggest you rig a fuel pressure gauge on a "T" in the rubber line to the carb. The clear fuel filters can look part or even mostly empty and all is working normally. If the fuel pressure drops off as it heats you know for sure it is a fuel problem.

Other possibilities might be electrical... ignition box bad, coil bad or maybe the magnetic pickup in the distributor. These can be temp sensitive.

 

I have been pondering a fuel Guage to be put in line like u said, I am 100 pecent positive it's a fuel delivery issue, I thought I had her fixed one time and she left me stranded so I pop the top of carbinator and she was empty so I filled the float bowl and drove a few hundred feet and once again no fuel in the bowl so I did this 19 times till I made it home

 

I had a somewhat similar issue with my 75 4x4 360 engine.
I too went with a different cap, new fuel pump/filter assy, new rubber fuel lines and rebuild the carb. still ran out of fuel while running.

My issue turned out to be foreign matter(fuel additive cap seals) in the gas tank.
Pulled them out and have had no issues since.

First try running with no gas cap to make sure you're not getting a vaccuum pressure issue, cheap and easy test.

Next, I'd suggest running the truck off of a 5 gallon gas can in your shop. If it keeps running you know something is up with your pick-up or tank. if it still dies out you can at least rule out the tank and pickup.
Tbruz

 

Thanks for the input I have had a can of gas next to the front wheel same issue and I have ran without the gas cap as well, still the same symptoms n I'd like to find the problem b4 converting to a electric fuel pump

 

It seems like you are sure its a fuel issue and have eliminated all likely possibilities... except a bad new fuel pump. One member (Mike00 ??)went electric because he could not find a functional new mechanical pump.

 

Besides hooking up a fuel pressure guage, getting another mechanical fuel pump could be another option before I go eletric, the part of this that's gettin the best of me is that the truck was fine, I had no issues like this, and she even did some work with a 16' car hauler couple months ago

 

Disconnect the fuel delivery line at the carb....put that end in a clean, suitable container, and hold it away from any hazard to you. Have some one crank the engine and see what happens.

You know the rest......

Could be a bad pump (diaphragm) from the gate...it's happened before.

 

It pumps fine until things get warm

 

How warm does it have to be before you see the issue?

Hydrolock?

 

Exactamundo!! Things tend to expand when warm/hot. I'll bet the diaphragm in the fuel pump is shot. When cold, it might work ok, but, when it gets warmer, the crack in the diaphragm opens up.

Pull yer dipstick ( no, not that one) and smell the oil....smell like gas/oil mixed? Yes? Then that would be yer fuel pump's bad diaphragm pumping gas through the crack in it, and back into the engine.

Oil/filter change time!

 

The filter/sight bowl may not look like any thing is going on . I'd verify the fuel pressure or flow before declaring it a fuel issue.