Grampa's Cj2a

It  helped some. I also have a return fuel line that goes back to the tank. The final solution FOR ME was pulling the manifolds off, separating them, then blocking off the heat riser. My heat riser and spring were functioning correctly, but there was a flaw in the manifold casting that made in  impossible for the flap to close off the opening and allowed hot gasses to continually circulate to the intake manifold and boil the fuel. with my friends help I made a sheet metal piece that fit the opening. We glued it in with JB weld and reinstalled. No more fuel boiling.

Here’s a google photos album with the few pics that I have. We tack welded the plat to the heat riser shaft and sealed it up with JB weld. Pictures look like there’s a notch in the plate, but that is just a shadow.