1F / 2F Fuel pump compatibility ???

[BigR]

I am in the process of replacing the 1F engine with a 2F in my 1970 FJ40. The pump on my F1 dose not have a return line yet the 2F pump dose. Can I use the F1 pump in the F2 block? If not, what can I do this the return line? All the smog gear has been stripped including the evaporator. I have no place to rout the returned fuel, any ideas?

 

[Pin_Head]

'79 and up have a vapor return line. You can use the early to '78 pumps, but you have to remove the insulator/spacer. Just remove the T fitting on the return line that goes to the pump vent and join the two ends together. If you don't have a vapor return line, don't worry about it.

 

[BigR]

Now I am even more confused. When i picked up the engine, It just had one hose connected to to the carb, another to a short section of fuel line with a fuel filter at the end. I assume this goes to the tank. The third outlet, I assume is the return. So it’s not a fuel return? Only vapor? Can I put a tee just after the fuel filter and connect it to this outlet?

 

[Pin_Head]

Fuel goes one way on carbureted engines: to the carb. There is a vapor return line that goes from the carb bowl vent and fuel pump can to the top of the fuel tank. You don't need this system for the engine to run. If you don't have appropriate fuel tank there is no where to connect it. Its purpose it to eliminate evaporative emissions. Without it your cab is more likely to stink of gasoline fumes, so you might consider running the hose somewhere under the truck so that the vapor goes out the back. You don't want to connect it to the fuel inlet (filter) line.