Going EFI whipple- fuel line questions (return line?)

[zimm17]

The kit came with a honk'n huge SX marine fuel pump (similar to aeromarine 1000). Do I put this after my external mechanical pump, or take it out of the loop? What about my merc fuel filter/water seperator? use it?

Then the regulated return line- I don't think I can get back to my fuel tank for a return line. So then should I get a "cool fuel" and pipe the return line into that upstream of the pump?

[The Hedgehog]

Not a Whipple but my Procharger called for the removal of the mechanical pump and it was replaced with a big Aeromotive. You put a block off plate in place of the mechanical pump. I would think that two pumps in line would really heat the fuel.

I also ended up with no return line but a fuel cooler. I have heard that a return line to the tank is better. I will probably go to that since Tex had an extra setup fabricated for me. So far I have not burned up a pump but I only have one season on it and don't have any long idle zones. I guess that a bunch of the issue would center around what kind of fuel pressure is required for the whipple unit. If you are running EFI is will probably be pretty high. Mine idles at 37psi and runs up to around 60. Carb units don't need them as they run much lower fuel pressure.

[MOP]

If your tank has no extra fitting you can bring the fuel back any decent place before the fuel pump, I have see a couple just T'ed into the fuel line. Like Mr. Green dump the mech pump!

[zimm17]

If your tank has no extra fitting you can bring the fuel back any decent place before the fuel pump, I have see a couple just T'ed into the fuel line. Like Mr. Green dump the mech pump!

Ummm...how do I get to the fuel tank?

If I can't, I read I can run it through a merc "cool fuel" then back prior to the pump.

[BUIZILLA]

you should have 3 or 4 in-out ports on the filter head itself, route the fuel thru a cooler and back to the filter head, thats how Merc does it on most of their MPI engines with standard fuel coolers.

[BigGrizzly]

Take out the mechanical pump! As for the return line- it all depends on the pressure you have to run. According to my friends 60 to 70 is marginal for a cooled jumper. Last August we had an issue with a old 20 fountain with a wipple it had run pretty well the year before. Last year it started acting up on long trips. After talking to everyone including Merc racing with no fix in sight. Garry said what if WE dump into the tank, we know that is a better idea for a long idling blower motor. so he put a fitting in a old gas cap and off to the lake we went. Problem solved. This was the only change made. It must have been the air density was different at this time. the boat now has a tank return

[The Hedgehog]

A down n dirty fuel return system is to get a tee welded up for the filler hose, with a small fitting to attach the fuel return ine to...

This is what Tex did and what I am doing as well. I have also heard of the problem that Griz is mentioning and heard from many sources that what these guys are proposing works.

[HallJ]

When I converted my Minx to EFI,
I spliced in a piece of 2"stainless tubing with a -6 an fitting welded to the side. I slid this assembly in the fuel fill hose between the deck and tank.
I also welded on a 1/4-20 screw to attach a ground wire from the tank to the adapter. Works quite well. Wish I had a picture for ya.

Jeff

[Traveler]

My setup is the A1000 in a supercharged application. At first I ran the return line through an oil cooler and back to the fuel filter inlet as others have suggested but didn't like the delay in clearing air from the system. Because I was able to run a line back to the tank I pulled my fuel sender and drilled a hole in the tank close to it then reached in to attach a bulhead. At this point I can probably remove the fuel cooler but until I need the water I'll leave it as is.

[zimm17]

Sounds good. I'll make up a T for the filler neck. Thanks for the inputs.