Please explain Vapor Lock...What is it?

[Glennster]

 I've asked a few guys what it is. One guy says it's when gas ''boils'' or ''bubbles'' in the carb, so the car gets way lean since the carb has bubbles in the bowl instead of liquid gas.......

 The other guy tells me it's when the heat is so extreme that the carb is starved for ''clean cool air''. Since there is too much heat and very little usable air to burn, you are effectively making your mixture real rich. This seems to be what's happening with my car. I pulled the plugs and some were wet and dark. They looked fouled.

 It reminds of what a guy told me once, he said there's 3 sides to every story, your side, my side and the truth......

[Skunkworks Challenger]

Vapor lock is when the fuel vaporizes in the fuel line or fuel pump. The fuel pump will not pump vapor and the engine starves for fuel.  Boiling fuel in the carb can cause lean problems and hard starting, or, no starting.  Most vapor lock is before or at the fuel pump.  And, don't believe the clothes pin hype.

[Chryco Psycho]

 
 Vapor lock is in the line & pump & it will no longer move fuel .
 Isolating the carb from heat will make a huge difference , this will interest you http://www.dodgecharger.com/forum/index.php/topic,52284.0.html . With alcohol in the fuel the problem is worse , the fuel evaporates more easily & the carb will be dry why you try to restart . Anything that can be done to reduce heat at the carb is a win .
 Also anything you can do to feed cold air to the carb will help .
Sounds like the carb is set wrong if the plugs are black , you may be over jetted at cruise or float level is too high . I cannot remember what carb you are using .

[72cudamaan]

Could you even have vapor lock with an electric fuel pump?

[73EStroker]

Could you even have vapor lock with an electric fuel pump?

This is possible if you do not have a recirculatiing return back to the tank. I get a little fuel partial boil after sitting for 15 minutes in the peak of summer but a short drive gets it back to running normal so no big deal.