540 BBC Carbed N/A convert to EFI fuel system set up?

[wet hull]

Thanks for any help. I have carbed 540 and converting to EFI. I have two fuel tanks and a 3 port Imco fuel valve. What are the options for hooking up the return lines? Hoping there are other options besides buying a 6 port fuel valve. Pic of new set up.

 

[zx14]

I’ve seen it done, you can T it back to the incoming line to the pump, but it is warm fuel, so you can run another fuel cooler before the T. But, the right way is a new superswitch.

 

[28Eliminator]

Filler neck T.

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[BamBam]

Filler neck T.


View attachment 760395


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^^^ NOT That...

There are a couple threads on here regarding this issue. I run a 548 N/A with EFI. Mine runs a secondary tank. I use low pressure pumps to fill a secondary/reservoir tank which is the feed for the high pressure pump. The high pressure pump supplies the fuel rails through a bypass regulator and the return line goes back to the secondary tank. I have a check valve to keep fuel from going back to the low pressure side.

 

[BamBam]

https://www.riverdavesplace.com/forums/threads/fuel-surge-tank-for-efi.193054/

https://www.riverdavesplace.com/for...content-efi-return-lines.196971/#post-3261318

There may be more threads but I recall reading through these two in the past.

 

[02HoWaRd26]

Any issue with this? This was my suggestion!

 

[Hdgasser]

Me and @LBZRCKS just went thru this exact same thing.

To kinda half ass it you can put in a cooler, return the fuel to the filter head and PRAY you dont have issues with Vaporlock or you can just buy a new switch and run a couple return lines.

Plumbing a new fuel system, only to find out you have to re plumb it wasnt really on my "shit to-do list" so we both opted to spend the damn money and do it right.

B.O.A.T

 

[Hdgasser]

 

[Hdgasser]

^^^ NOT That...

There are a couple threads on here regarding this issue. I run a 548 N/A with EFI. Mine runs a secondary tank. I use low pressure pumps to fill a secondary/reservoir tank which is the feed for the high pressure pump. The high pressure pump supplies the fuel rails through a bypass regulator and the return line goes back to the secondary tank. I have a check valve to keep fuel from going back to the low pressure side.

Why NOT that??

Seems like a hell of alot easier than installing a whole other stand alone fuel system fed from the fuel system currently in the boat??

 

[BamBam]

Why NOT that??

Seems like a hell of alot easier than installing a whole other stand alone fuel system fed from the fuel system currently in the boat??

If you have a selector switch (as indicated by the OP) to pull from either the port OR starboard tank you would then need to have an additional selector to send fuel back to the appropriate tank. Maybe I mis-understood the picture, but it appears to be a return line that goes into the fuel tank fill line which would return ALL fuel to ONE tank.

With EFI you have no "float-bowl". The float bowl in a carburetor acts like a surge tank, if the fuel runs away from the pick-up for a second you still have fuel to run on. In a boat it is a good thing to have a surge tank whether that is a float bowl in a carb or a true surge tank in an EFI set-up. He's running a 540 and probably looking for good HP numbers. A good fuel system is part of the cost to switch over to EFI if you want to protect your investment in horsepower.

 

[wet hull]

All good info. I will pick up the 6 port fuel valve. No rush on this conversion until end of summer. Boat runs to good on the carb to chance ruining summer. I currently have the Aeromotive filters and pump. I will do the system top notch. The surge tank from Kinsler looks to be a good add on.

 

[Husqy510]

I'm curious what motivated you to switch to fuel injection? Was the carbureted deal tough to run?

 

[Hdgasser]

If you have a selector switch (as indicated by the OP) to pull from either the port OR starboard tank you would then need to have an additional selector to send fuel back to the appropriate tank. Maybe I mis-understood the picture, but it appears to be a return line that goes into the fuel tank fill line which would return ALL fuel to ONE tank.

With EFI you have no "float-bowl". The float bowl in a carburetor acts like a surge tank, if the fuel runs away from the pick-up for a second you still have fuel to run on. In a boat it is a good thing to have a surge tank whether that is a float bowl in a carb or a true surge tank in an EFI set-up. He's running a 540 and probably looking for good HP numbers. A good fuel system is part of the cost to switch over to EFI if you want to protect your investment in horsepower.

The filler neck fitting is just a way to get around not having another bung on the tank. Your right still has to have the switch to return to the tank hes pulling from.

I am all well too familiar with spending a shit ton of money to do efi right. I'm going from a HO to what started as a 500efi with all the factory cool fuel returnless crap to a full aftermarket return system, with 6 port switch, Holley hp efi, and a complete holley mpfi setup, 509 with aluminum heads. Should run pretty ok I think.

Gonna be fun!!

 

[wet hull]

I'm curious what motivated you to switch to fuel injection? Was the carbureted deal tough to run?

Plain stupidity . My motor runs flawless as is. Zero issues, tons of torque, zero complaints. Just redid entire boat and need a project. Got a smokin deal on the EFI system. Guess I am hoping for the wife to be more comfortable to drive it, be able to monitor the motor other then just my water temp and oil pressure. Not convinced it will give me any better results but worth the try. May help resale as well.

 

[wet hull]

The filler neck fitting is just a way to get around not having another bung on the tank. Your right still has to have the switch to return to the tank hes pulling from.

I am all well too familiar with spending a shit ton of money to do efi right. I'm going from a HO to what started as a 500efi with all the factory cool fuel returnless crap to a full aftermarket return system, with 6 port switch, Holley hp efi, and a complete holley mpfi setup, 509 with aluminum heads. Should run pretty ok I think.

Gonna be fun!!

Can you get me a parts list of your ECM and harness? Mine came with MEFI 4B but I want to do continuous mapping

 

[Husqy510]

Plain stupidity . My motor runs flawless as is. Zero issues, tons of torque, zero complaints. Just redid entire boat and need a project. Got a smokin deal on the EFI system. Guess I am hoping for the wife to be more comfortable to drive it, be able to monitor the motor other then just my water temp and oil pressure. Not convinced it will give me any better results but worth the try. May help resale as well.

Cool, good luck with the project. I have a carbureted 540 in our boat, so I'm curious to see how it goes.

 

[wet hull]

Cool, good luck with the project. I have a carbureted 540 in our boat, so I'm curious to see how it goes.

Will do a build thread on it. Always happy to be the Guinea pig

 

[oldschool]

I have a carbed turbo set up and return fuel from the regulator to the filler neck on the saddle tanks. As stated, you need to have the tank selector valve match the return selector valve.

 

[wet hull]

Got some news. IMCO will convert your 3 port supervalve to a 6 port. Ship to them and for a fee they will convert.

 

[Maestro]

What's the fee?

 

[wet hull]

What's the fee?

$200 plus shipping

 

[Maestro]

Good deal, thanks

 

[wet hull]

Next question. Bought the Holley HP EFI, dual sinc distributor, oil, fuel pressure sensors. Guess they are made for this ECM. Now that I have gone overboard, do I go coil packs? Already have the MSD 6 ignition box. Is there any benefit on a marine motor that I will notice?