I have a 1963 ready for restoration and it has a fuel line leak.
We are going to replace the entire fuel line from tank to pump but noticed there is a second line approx. 1/8″ in diameter coming from the fuel tank
following exactly the same path as the fuel line.
As the fuel line comes out of the drivers fender well in to the pump, this other thin line is there next to it but not connected.
Is this second line a vent? Can I cap it or not?
Thanks for your answer.
Hi Tony –
The engine originally would have had a fuel pump with three ports and the second line from the fuel tank was connected to the third port. This design with the third port and the second line to the tank was developed by Ford engineers to reduce or prevent the possibility of fuel vapor lock on these engines by re-circulating warmer fuel back to the tank and therefore providing cooler fuel in the lines near the engine during hot driving conditions. Some engines (but not all) of this type with the two port fuel pump located on top at the front of the engine are known to suffer from fuel vapour lock under certain driving conditions. Many of these three port fuel pumps when they eventually failed were replaced with conventional two port pumps and the second line to the fuel tank was capped with no problems. Some owners found it necessary however to revert back to the three port design. If you are restoring your Lincoln for show or possibly for a serious “judging” event you will want to install a three ported fuel pump as you will lose points. For more information and availability on the original style pump contact Chris, George or Al at Lincoln Land and we will help you decide what might be the best choice for you.