The fuel system is as follows:( All Impco mixer (carb) - CA100, regulator/vaporizer (as installed- Model J ) & fuel shut off solnoid. If I were you I'd get the mixer diaphram, replace the Model J with a model "Cobra" & replace the electric solnoid.

They've cheapened up the Model J - I have all sorts of problems with them now- the Cobra looks & mounts the same as the J but internally it's updated to a newer design.

Once the new parts are installed, trace the wiring to the solnoid- it should go either to the ign coil or to a round silver device hooked to the intake manifold. Either way- you should see 12V at the solnoid while cranking.

The system works as follows: the mixer senses a vacuum while cranking- the vacuum signal is sent to the regulator thru the fuel feed line which opens the ports in the regulator which in turn starts to let fuel flow to the mixer. The electric solnoid is a safety feature which stops fuel flow when the ignition is off. If equiped- the round silver device shuts off current to the solnoid if no intake manifold vacuum is present- regardless of ign switch possition.