Fuel tank liquid check valve?

That really sounds like you have your gas filter in upside down or you have a pinhole leak in the gas line on the suction side of the pump.

The gas filter has two outlets. The center outlet goes to the carb and the 'top' outlet goes to the return line. If the return line isn't at the top, the gas will syphon back to the tank when it sits causing an air lock.

A pinhole leak can do the same. The line is a suction line so gas doesn't drip, but air can still get in when it sits. You need to look for a small stain on the line, usually near a clamp.

The check valve is indeed on the gas tank vent, so it doesn't affect flow.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Ghostbuster wrote:

That's right. The check valve is there to prevent fuel from backing up into the bottom-vented charcoal cannister mounted on the firewall if you over-fill the tank, and then out onto the ground. Depending on the year, two lines from the top left side of the tank go to the check valve in the left rear fender well, one line runs forward to the charcoal tank (mid-seventies Jeeps had different plumbing, four lines from the fuel tank and more parts).

Pumping the gas pedal 30 times is about 27 wasted moves. If I recall correctly the accelerator pump is bone dry after three squirts with no pressure.

None that I'm aware of. How old is your fuel pump? I haven't looked forward yet but I'm sure that Mike has mentioned the proper orientation for the fuel filter (return line to the top, always).

If you are really curious, you could pull the top off the carb float tank and see if there's fuel sitting there. Before you pull that, you should also see if the choke is closing when cold.

Be sure to let us know what you find.