Vapor lock?

johnny78cj5

New member
Have a 78 cj5 with the 258 6cyl when it gets a little warm out(80-85 degrees) it act like it has vapor lock but it's actually the carb that is over heating and vaporizing the gas before it can get to the motor.
Has anyone had this problem?anyone have a fix for this?
Thanks Johnny
 

Do you have a return line hooked up? Typically if your experiencing this it usually comes from no return line or the return line is connected to a vent on the tank instead which decreases flow. I would also check for kinked lines for the return.
 
get all your lines away from a heat source, exhaust, manifolds. you can buy header wrap and wrap your lines, local auto store might have it.
 
Thanks for the tips, I don't have a return line hooked up so that's probably it getting the fuel lines away from the exhaust manifold would be tough since the carb sits on top of it but I will reroute as much as I can and wrap what I can't.
Thanks again
Johnny
 

also, you should have a thick paperboard or phenolic spacer between the carb and the intake. if you don;t, the intake will for sure make the carb get hot and cause your issue. the phenolic or paperboard spacer looks brown and is about 1/3 of an inch thick compared to the rest of the stuff between the carb and the intake. you should also have a heat shield between the intake and exhaust but it usually deteriorates after a few years and you have straight exhaust radiant heat cooking the intake
 
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