Ok, I Am Officially Getting Tired Of This Crap

There are reed valves in the fuel pump. I don't think there's any check valve per se.

 

Replaceable spring-loaded valves as I recall. Button shape units. Check valves in my book.

 

Check or diaphragm / (reed) valves are the same thing. If one of them is busted, that's your problem , as your describing.

 

A reed valve is one type of check valve.

The ones in an F-head pump are technically in-line check valves, with a spring loaded disc rather than a flap.

Check valve - Wikipedia

 

Yeah , pete Sir , I believe we're both gett'n at the same thing. For $ 60 , mickeykelley could get a new f head fuel pump or rebuild kit & most likely fix his problem.

 

Or begin by testing the present one for FSM specification performance.

 

YF

 

Today’s update. I backed Willie into the exact same position yesterday when I got back from errands. Started right up so we went for an hour long drive. Up and down roads here in town. Some were very steep and not once did we starve for fuel or have any issues. I intentionally picked steep roads that would put the pressure on and get the bowl in different positions. It was again warmer than that first day and climbing up and down all those hills, sharp turns, etc without a single hiccup. I’ve decided to tow him back to Texas to make it easier to change out the pump and add an electric. In the garage on cement instead of out in the cold on rocks, grass and dirt, plus all the tools there should I need them.

But I will keep testing until we head back.

 

I agree with the idea it could be the check valve in the fuel pump, which is supported by the angle the Jeep was parked made a difference, but what caught my attention is "I took off the clamp" which I assume means part of your fuel line is a rubber hose with clamps. That is a weak point in the system and why I have no clamped rubber hose in my fuel lines. A very tiny leak where the hose is clamped may not be leaking fuel, but it can let air into the system.

 

The reason for the clamps is a temporary bulb filter as I found a very little bit of junk at the bottom of the carb bowl once. There is are filters in the factory system, except for that original glass bowl AC. Hence, why I looked for and found a NOS one. It’s just time to install it. I’ve decided to tow Willy back to Texas when we head out and work on this in a nice garage.

 

I have a AC paper element filter on my CJ2A, and have a NOS Carter ceramic element filter I plan to install on my CJ5 which currently has an in-line filter at the tank end and another at the carburetor.

I have used rubber hose and clamps many times over the years, usually when I didn't have something better. That is why I know they can cause issues.

We won't know if this has anything to do with your problem until you test some more, but I once fooled with similar issues as your's until I felt like yanking my hair out and it turned out to be related to air getting in the line from a rubber line connection to a steel line, so it is something to think about.

Good luck.

 

Took another very long ride today with more hills, including some steep ones. Willie drove fine. Ready to put fill him up tomorrow.

 

Back at home and getting ready to start the changes before trying to taking Willie back to the mountains at Christmas. Looking at the adding electric fuel pump and have a few questions. As I understand it, electric pumps are best set to push and not suck the distance. With that premise, closer to the tank is better, but it seems to me that mounting one under there would really expose it (and possible flammable leaking liquid) to potential abuse and damage, rock/branch kick up. I know there is the frame rail to help protect. Thoughts? Is that where most of you locate it?

 

In the tank is the best application for electric fuel pumps.

 

Mmm. I would put the pump in the frame channel. If you want more protection, make a shield that's anchored to the frame. Drilling near the center of the web (not the rails) is fine for anchoring your pump and/or shield.

 

In a CJ?

 

Yep......Sorry 'bout that , mine is a '75 CJ5 / 1984 Buick hybrid that is designed to have it that way. Your Jeep is , with the under seat tank should be like Tim just suggested. I'll butt out.