[jhein]

Originally Posted by Jay S

No matter where you put the pressure regulator fuel pressure at the pump is basically the same as the pressure at the carburetor . The only difference in pressure at different points in the system is from friction loss in the line.

It would take another regulator in the system to effect the pressure at the pump. Such as one set at 40 psi to force fuel thru a smaller line, then another to drop the pressure more for the carburetor. That would force more fuel thru a small line, it fix’s one issue, but then the fuel pump wears out sooner because it is working harder, especially without a pump controller.

Skip Fix early mentioned he noticed the fuel got hot when he had is Mallory 140 pump pushing thru a mechanical pump. That Mallory pump was a lot bigger than the mechanical pump, it is a 140 pump pushing thru a 80 pump. That was a miss match kind of similar to how the 255 pump is with 3/8” line feeding a carb.

OK, that makes sense now. So the regulator just bleeds off enough fuel through the return line to keep the pressure wherever you set it for the whole system. And I can still run a 3/8 line from the regulator to the carb, if I keep the regulator before the carb, correct? So then really, I'll have all these expensive fancy fittings for a 7 psi system? That's kinda funny.

[Jay S]

Originally Posted by jhein

OK, that makes sense now. So the regulator just bleeds off enough fuel through the return line to keep the pressure wherever you set it for the whole system. And I can still run a 3/8 line from the regulator to the carb, if I keep the regulator before the carb, correct?

Yes you can run the 3/8 line to the carb from the regulator.

It is generally best to use a T in the fuel line before the regulator, and put the regulator after the T that feeds the carb, it maximizes the flow to the carburetor.

[jhein]

Originally Posted by Jay S

Yes you can run the 3/8 line to the carb from the regulator.

It is generally best to use a T in the fuel line before the regulator, and put the regulator after the T that feeds the carb, it maximizes the flow to the carburetor.

So just the input and return lines will be used on the regulator and plug the output side?

[Jay S]

Originally Posted by jhein

So just the input and return lines will be used on the regulator and plug the output side?

Yes. That is the best way to do it, but it is not always easy to make it look nice. If it gets to cumbersome looking just plumb the output from the reg to the carb.