fuel lines- easy one for you gearheads

[dave5237]

Hi guys. Here's a easy one for you guys. Hooking up my fuel pump ( mechanical pump ) two fuel lines under hood. One's a 1/4 line and one's a 3/16 diameter line. Which line is the supply and wich one is the vent back. I could trace it out but what a pain. I would think the vent would be larger so it vents properly. I started filling the tank hoping it would drain out its lower point but no gas yet. I know one line ( possibly smaller one ) goes to the vapor evaporator. Your help please.

 

[Cranky]

What is this on? Generally, the smaller line is the return....

 

[dave5237]

sorry 440 engine 1968 gtx

 

[Revhendo]

Did you mean 5/16th? That would be the feed line to the pump. The 1/4 is going to be the vent. (?) (Did they use return lines in 68? I honestly don't know).

 

[Slantsixdan]

5/16" is the supply line. 1/4" is the vapour return line.

 

[dave5237]

yeah i made a mistake. i said 3/16. It looks like 5/16 is the fuel line ( the bigger line) and the 1/4 line is the vent line ( small line ). if you measure the outlet into the pump it measures 5/16. if you measure the line off of the vapor seperator it is 1/4. thanks guys. if you dont agree let me know.

 

[Patrick]

Hi guys. Here's a easy one for you guys. Hooking up my fuel pump ( mechanical pump ) two fuel lines under hood. One's a 1/4 line and one's a 3/16 diameter line. Which line is the supply and wich one is the vent back. I could trace it out but what a pain. I would think the vent would be larger so it vents properly. I started filling the tank hoping it would drain out its lower point but no gas yet. I know one line ( possibly smaller one ) goes to the vapor evaporator. Your help please.

The big line is the supply line.