vapor lock/ Fuel pump failure-input please

A year ago, after 3 engine rebuilds my 47 CJ2A seems to be running OK, not awesome, but OK.  I put maybe 100 miles or so on it. I then tow it to our cabin in the Sierras, it still does ok. It seems to run out of fuel occasionally, but then starts right back up. This happens a few times over a long weekend. My wife was driving most of the time so I blame it on her. When I return home, I replace the fuel filters (one before and after the fuel pump) and go for a long drive when...it runs out of gas. I open the hood to revel an empty fuel filter between the pump and the carb. (fuel gauge does not work, and I've had fuel stolen from vehicles) I walk home to get  fuel and my truck, when I return the Jeep starts right back up. I make several short trips only to have the same problem; a few minutes of driving the it behaves like its low on fuel. It has a full tank of good fuel. I park it and don't really use it for 11 months. Pull it out and what do you know... the problem did not fix itself. The Jeep must need more time to hibernate. All underhood components are new. Carb was done 18 months ago by a shop that has done dozens for me. Fuel pump tank and lines were new about 3 years ago. The Jeep can idle for an hour with no issues, and starts up almost instantly after sitting for months.
The previous Sunday I take it out, armed with a tool bag and an idle afternoon, I go for a drive. After 15 minutes it dies, right in front of some 10 year olds that:
1. Are selling a face painting experience for a dollar
2. Wonder why I would drive something that appears so dilapidated.

As always fuel filter is empty- disconnect the fuel line from the carb, I get pulses of fuel when I bump the engine over.

Remove the top half of the carb to revel a spotless fuel bowl, with almost no fuel. Needle and seat look fine, although the metering rod has a slight crook in it. Images online suggest it should be straight. I poor some gas into the fuel bowl, reassemble every thing and the Jeep starts up. While reving the engine I can see there are not regular pulses of fuel into the fuel filter and it ultimately dies out. Do mechanical fuel pumps fail intermittently? I always thought it was an all or nothing deal. The fuel pump is single action with a glass dome that remains full of fuel. I'm using the thick carb base gasket from Walcks, so I don't think I'm imputing any more heat into the fuel bowl. What am I missing?

Is fuel poring out freely if you open a junction just before the fuel pump, mine does this if fuel tank full.

I have had a fuel filter colapse before. If you are getting fuel after the fuel pump  and it is not filling the filter after the fuel pump this sounds logical.  Fuel filter is blocked.  If it is going through the filter after the fuel pump then the next thing is the needle valve in the  carb. or the float is stuck up. After that it is the accelerator pump and jets.

Edited by p3ferris - 25 Sep. 2012 at 2:03pm

Crack the fuel tank cap and take it for a drive, if the vent is clogged then you will eventually pull a vacuum and the engine will stall. Thats why it was suggested that you check the cap vent. 

Orville... There is an outside chance that your fuel pump's lever is not fully contacting the cam lobe that drives the pump. I've experienced this twice - it seems that a loose pump lever can slide off the aft end of the cam lobe and only work some of the time (how it re-engages with the pump again, I don't understand). Here is a photo of the fuel port that shows the cam lobe on this gear-driven engine that is slightly forward of center of the port. This caused the same problem you describe. Removing the lever from the pump and bending it so that it doesn't ride on the edge of the lobe solved the problem. Not sure this is what you are experiencing but worth investigating. Study the pump's lever to see if the cam is wearing evenly on the lever. .. R

Edited by JeepRoger - 26 Sep. 2012 at 3:13pm