Inverted Flare Tube Nuts

[Quarterwave]

Hi everyone,

I have a Carter P4389 electric fuel pump that I am trying to incorporate into my 5.7.

As part of the installation, I am running double-flared fuel lines from the filter to the pump and then the pump to the carburetor.

The in/out connections on the pump take 1/4" NPT nuts. The line that I am trying to use is 3/8".

My first question is - What size nut do I need? I cannot find a 1/4" nut to suit the 3/8" fuel line.

My next question is - What size nut will I need FROM the fuel filter (to the pump)?

.. and my last question is - What size nut will I need INTO the Edelbrock carburetor that I'm running (Edelbrock Performer Series 600 cfm marine carburetor)? The specs from the manufacturer say 3/8"? How can that be if the fuel line is 3/8"?

NOTE - in another thread (https://forums.iboats.com/forum/eng...-outdrives/10530329-stainless-steel-fuel-hose) Scott Danforth had mentioned I do not have to use metal fuel lines when running them over the engine - and to consider using Coast Guard-approved A1 or A2 hose. Scott if you read this - what SAE do I need to exceed?... I'm thinking aloud - it might just be easier to use that hose if it's safe to do so. I am just concerned that the hose will melt when resting on the manifold - and as my engine is mounted underneath a sundeck, any fuel leaks will be big problems!

Any help is appreciated.

 

[Bondo]

and my last question is - What size nut will I need INTO the Edelbrock carburetor that I'm running (Edelbrock Performer Series 600 cfm marine carburetor)? The specs from the manufacturer say 3/8"? How can that be if the fuel line is 3/8"?

Ayuh,.... It's a 3/8" Tubing nut, uses a 5/8" wrench, same as automotive brake line fittin's,.....

and to consider using Coast Guard-approved A1 or A2 hose. Scott if you read this - what SAE do I need to exceed?...

No SAE, it'll say Coast Guard approved A1, or A2, right on the hose,........

 

[Quarterwave]

Thanks Bondo - so an approved hose is safe to use for both the fuel filter to the pump, and then the pump to the carburetor?

Also - if I use a hose, what type of connector will I need to find for the:

- Fuel filter outlet
- Fuel pump inlet
- Fuel pump outlet
- Carburetor inlet

Thank you.

 

[Scott Danforth]

barbed.

 

[Quarterwave]

Thanks Scott.

What size nut will I need from the fuel/water separator (to the fuel pump)?

 

[Bondo]

The in/out connections on the pump take 1/4" NPT nuts.

Thanks Scott.

What size nut will I need from the fuel/water separator (to the fuel pump)?

Ayuh,.... Looks like 1/4" pipe thread hose barbs,....

 

[Scott Danforth]

1/4 NPT x 3/8 hose barb