Van has been sitting for about 3 years. Engine will not run. Everything is stock. New battery, engine will briefly fire up with starter fluid and/or gas injected directly into carburetor. Has about 1/4 tank per gauge (5 gallons new gas).
Took off fuel line to fuel pump and no fuel was evident.
Injected air back into fuel line to the gas tank and could hear air bubbling in tank.
Connected a manual transfer pump to the fuel line (at the fuel pump) and could draw out gasoline from the tank, but when the transfer pump was disconnected no fuel continued to flow. There was no evidence of gasoline leakage under the vehicle.
Suspect possible small leak in any fuel hose segments (or the steel line itself) that run from the fuel pump to the tank , but can't tell where it might be because the steel line runs up into the frame and it is hard to track without putting the van up on a lift and possibly dropping the tank.
Couple questions: Does the steel fuel line run continuously from the fuel pump to the tank or are there hose segments? Is the mechanical fuel pump system gravity fed? Can the mechanical fuel pump draw fuel out from the tank , if so what vacuum or lift does it produce? I'm going to install a new mechanical fuel pump and considering an electronic fuel pump. Any other ideas or suggestions welcome.

 

Lets see what you get after installing the new fuel pump.
As far as the lines from the tank, best to lower tank once and verify no leaks from all lines. If you can apply a small amount of air press to each line and have the lines disconnected from the fuel pump, spray with soap solution. There are no short cuts for this. If any are evident,must be repaired. Once proven to be leak free there is always a possibility of problem with in tank module. Not very common.
Mechanical fuel pump is driven by cam and rod , either of which could be worn, but not very common either.. The arm of the pump gets sloppy and worn , most common problem. Lets see what you find.

 

Problem solved, engine now runs fine. I installed a new mechanical fuel pump and rubber hose that connected the steel line from the tank to the intake of the fuel pump. The old rubber hose had a soft area where it bent connecting to the pump. The old mechanical pump didn't appear too worn, but noticed uneven wear on the pump arm connecting to the engine eccentric cam (see photo), only about 1/2 of the side of pump arm appeared to make contact with the cam. Uncertain whether this is a sign of cam wear or an uneven installation of the old pump, suspect the latter.


Uneven wear of pump arm where it contacted the cam.