Do you believe that? Hello Mark and Net
Some people think of vapor lock as a void or pressure area that fuel will not pass. I found this definition on the internet. I also went into a Sunoco site which listed some temps and the #260 sticks in by head from that reading. Fuel Terminology by Rich Rohrich Vapor Lock - Rapid formation of vapor in the fuel lines or carb, that causes a restriction in flow. Vapor formation begins to occur in fuel lines, pumps, etc. when the fuel reaches a temperature where the vapor pressure of the fuel is equal to the pressure in the system. Gravity feed fuel systems (positive pressure) tend to be less prone to vapor lock than snowmobile type vacuum pump systems where negative pressures exist. End It is a dynamic process in which vapor pressure is created by the boiling fuel. I was able to watch vapor lock once in a boat, that had a mechanical fuel pump, clear plastic filter and metal tubing. The vapor lock was caused by heat transfer from the engine block to the pump and tubing, in the enclosed compartment of the 440ci engine. You could actually see the fuel boiling (vapor lock) in the plastic filter. I would suspect that if the temp inside the engine compartment gets high enough to cause the fuel to go to vapor that, even though the pump will continue to push the vapor and what ever fuel it can, that the quantity of fuel exiting the carb could and would not be sufficient to maintain the correct ratio. Once it starts boiling, it will continue until the temp in the compartment decreases. As a guard against vapor lock, some Piper aircraft place the pump and gasolator into a compartment which has pressure air from the cowling ducted to it. The use of fire sleeves is another way to prevent heat from getting to the fuel lines. My turbo KR will probably need more Heat protection and or cooling air, in the summer. Orma Southfield, MI N110LR celebrating 20 years Flying, flying and more flying http://www.kr-2.aviation-mechanics.com/
