Fuel starvation intermittent problem troubleshooting.

I got nearly stranded twice now with my Jeepster. Both times the fuel filter was dry when it died. Both times, letting it sit for a minute and cranking it for a LONG time got it going again. I actually saw the filter filling up as it idled the first time, with some air bubbles coming into the filter. The second time yesterday I was in town and coasted onto a side street. Cranked it a long time, nothing getting into the filter, then finally it began to flow and ran fine the 4 miles home. The tank had gas both times. The fuel tank & pickup are new poly. The fuel line is new, the filter is new and the mechanical fuel pump was new in '95, and looks new, though it was never ran and sat open the whole time. (The glass bowl looked full during both no gas events).
I can only think of two explanations, either a piece of something blocking the tank inlet which seems unlikely since it was all new, or a bad fuel pump, though I don't know why it would work then stop, then work again. Anyone ever have a similar experience? The replacement pump is on the way.

Now that I think of it, the fact that the pump glass bowl looked full should eliminate a pickup blockage as the cause.

Tank venting ???? If your tank doesn't vent, your pump can't draw fuel cause the vacuum in the tank is stronger than the pump can produce. Or you are boiling fuel somehow in the line before it gets to the carb. When you take the fuel cap off the does it sound like air pressure equalizing ? filter between pump and carb, or pump and tank ?

I agree with two-bit on this. Run it for a ride with the gas cap loose.

I had thought of that, but the gas cap is an old original Studebaker locking cap and it barely even fits tight until you wiggle it around and get both tabs latched. Maybe somehow it is making a good seal, I'll have to make sure its vented. I just got my new fuel pump in the mail. I'll install it and make sure there is a vent hole in the cap. I know what you mean though. If it does it again, I'll take the cap loose and make sure. My '85 Honda Civic sucks so hard on its cap it about takes two hands to get it loose and then is makes a whoosh when you break the seal, but it never misses a beat.

I swapped on the new fuel pump and used a drill to vent the cap.

I'll just buy a new cap. It did have a good rubber gasket and may have been airtight. It came with the car but is pretty pitted. I did check the gas hoses and one made a sharp turn, it may have tried to kink under suction. I straightened out the line to make a straighter shot to the fuel pump with no sharp turns for the hose. If that doesn't fix it, I'd be surprised. The fuel pump is probably good but I'd rather cover all my bases before I have to ask for help in the middle of the road again!

Air infiltration into fuel lines.

Old rubber fuel lines develop cracks. These cracks allow air to infiltrate which diminishes both pressure and flow rate. You won’t see any gasoline leakage.

All the hoses are brand new. Heck, EVERYTHING from the gas tank to the carburetor are brand new. Drove it last evening. It had some high RPM stumble but ran perfect except then (I had to make a half mile on the highway at higher rpms in 3rd since I don't have all my overdrive parts) The delco distributor I'm using doesn't have a vacuum advance which may contribute to that.

Since you're getting fuel farther down the line, it may not be this, but I'll share anyway.
I put a new plastic tank in my wagon. The pickup tube was not soldered completely to the fitting that exits the tank. Mine behaved like yours. I attributed it to vapor lock as I live in Florida and it's hot here. I could be driving down the road and it would stumble then die.
As you have, all my lines were new, new tank, rebuilt fuel pump.
Hope you find your problem. I suffered with mine for almost a year before I decided to check the pickup tube. I haven't had a problem since.

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It very well could be that. It's just the last thing I want to check. I drove it today and it did some misfiring at high rpm driving but smoothed out when I let off and lowered the rpms. That could be a different problem.
The next 2 times I drove it for maybe 8 miles each it didn't miss a beat. I'm trying to convince myself it may be over it. Probably unrelated, but I still have the points that were in it when I bought the used distributor off ebay. It's an oddball Delco 1112432 from 1959-1960. I checked and OReillys has them in stock, so I'll get a set tomorrow, and a condenser. I don't know what the opinion is on 12v conversion on condensers, but it is still the 6v condenser.
Since the points set was used on different cars until the '60's there should be a matching one from a 12v configuration and I'll get one of those too. That might solve the high rpm miss? I also haven't set the timing except by ear. The original plan was to junk the body and part it out, but after buying enough parts just to hear it run, I decided to get it on the road. That's why I didn't go a modern distributor, I just wanted to get it running as cheap as possible to sell it since nobody wanted to pay more than a couple hundred for a non running 134 that was supposed to be rebuilt in '95. Can't blame them.

I was putting gas in it today and for whatever reason it is very hard to get gas in. You just have to barely squeeze the handle or it will belch it back out. It should just be a big hole all the way to the tank. I can't imagine what's going on but I'll investigate after I run this full tank out if I can't see anything wrong from the outside.

Fuel fill problem sounds like a tank venting problem. I have seen this with multiple vehicles that use an electronic venting system. I know yours is not electronic, but it really sounds like a tank vent problem. What kind of a vent does it have? Not familiar with Jeepster tanks. The originals I would guess vented back out the fill neck. What about your replacement tank?
I know I keep going back to this, I maybe wrong, but I really suspect something is wrong there.

I actually drilled a small hole (1/8") through it under the lock flap to make sure it was vented. It seems to have gotten over it for whatever reason, but the hole was drilled in the midst of the problem with no effect. Then it had an uncontrollable flooding problem that was solved with a fuel pressure valve and lowering the float level. Seems to be happy now. When it's happy, I'm happy.