I was able to find the WUR with your directions (which is located just below the intake for the rearmost cylinder). I didn't know where the ignition amplifier was, so assuming that the reason for unplugging that was to protect the ignition points, I unplugged the main lead for the distributor. I then left the key in the on position for a generous 2 minutes. The WUR was as cold as a stone...

We found a PDF of how to disassemble and reassemble the WUR, but of course this requires new bits to put in it. Does anyone know where the parts to rebuild the inside can be gotten, without using another used unit for parts?