[ossiblue]

Are you able to blow air through the outlet line of the wur (detached from the wur) which goes back into the tank?

Just to be sure we are all on the same page, did you do the following things (not necessarily in this order)?

-Connected fuel pressure gauge set between the fuel distributor and the wur, with the shut off valve on the wur side of the gauge.
-Shut off the gauge valve to the wur, disconnected the electrical connection to the heating element, and started the fuel pump to get system pressure reading.
-Opened the valve on the gauge set and the pressure did not drop.

-Disconnected the outlet line from the wur (or disconnected the line where it enters the return tank tube?) and connected a tube to the outlet to collect the fuel.
-Shut the valve on the gauge set and started the fuel pump.
-Slowly opened the valve to allow fuel to the wur but didn't notice any fuel coming out of the wur outlet.

Does that summarize what you've tested? One very important detail is bold printed--the line connected to the outlet. If you used original line to route fuel into a jar and nothing came out, it's possible the line is clogged.

As you surmise, the wur is very simple--just inlet and out holes separated by a very narrow chamber that changes volume via two thin discs pushed up by a pin/spring mechanism. Since you are able to blow through the wur ports when all pressure is off the diaphragms, there is free flow through the chamber. If the return line to the tank is also clear and you have already disassembled/reassembled the wur, you may want to try the following: Hook everything back up, including the gauge set, but don't connect the electrical heating element. Start the fuel pump with gauge open. Begin to gently knock the pin for the bimetallic lever down into the wur housing. Do you see any drop in pressure? Continue until you are sure the pin has moved low enough to release all pressure off the diaphragm. Still no pressure drop? If still no pressure drop, I'm stumped.

BTW, did you check to see if your gauge set allows air to pass through when the valve is open? Just had to ask as it could be a problem with the valve on the gauge set, seeing that it's new.

edit: couple of posts while I was typing. Return line is not clogged. Suspect the gauge valve.