Vapor lock

Boiling gas in the tank sounds really weird. ??? :h I have a 1986 J-10 jeep, 360, carbureted. On an elk trip to the Flagstaff area, 8000' I had about the same trouble. On an off road hill pull with a small trailer it quit. I figured it ran out of air and choked up. . Started up and continued to the back country camp. On the trip back to the Phoenix valley I had "vapor lock." Bottom line, what I think was happening, the block was overheating, heating the fuel as it entered the carb. not necessarily in the lines. In other words, the block heat was radiating into the carburetor. The water temps were high but not boiling. I had pipe insulation over most all the gas lines. I had replaced the stock radiator years before with a four core but took it to a shop to have it rodded and boiled. My "new" rad was partially clogged..So far, no problems. I don't know if this makes sense to any mechanics here but this is what I've found to be MY problem.. Good luck..

I remember adding an electric fuel pump to solve a vapor lock problem. Bypassed the mechanical and used an inline electric fuel pump.

It's been so long since I've even heard about vapor lock, I can't remember all of the tricks. By 1987 I'm pretty sure you should have a closed fuel system which means there should be no way for the fuel to boil out the cap. You may need to replace the cap.

Your only hope is to convert the engine to fuel injection with an in-tank pump. Other than that, stay put in hot weather and only buy gas that has no ethanol. If ethanol is all that good, how come they have to give it a 1 psi allowance on Reid Vapor pressure.

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