EFi fuel system questions///fuel return line with two tanks

[Cdog]

Boat is a Howard 21 RC with I/O. Ive got two tanks with a switch for L or R tank running a carb set up. How do I run a fuel line return once I go efi? How do you plumb this kind of set up?

I’ll be putting in new fuel cells this coming winter. Is there any pre planning I should consider when ordering new fuel cells?

 

[BamBam]

Boat is a Howard 21 RC with I/O. Ive got two tanks with a switch for L or R tank running a carb set up. How do I run a fuel line return once I go efi? How do you plumb this kind of set up?

I’ll be putting in new fuel cells this coming winter. Is there any pre planning I should consider when ordering new fuel cells?

I think you have a couple options. 1. Get a fuel selector that has the ability to return fuel to the appropriate tank. 2. Run the fuel back to a small third tank. 3. I'm sure there are more options that will be posted up.
I personally run a third tank and would do that with EFI in a marine application anyway because you have a constant supply to the high pressure pump and face less chance of your fuel running away from the pick-up and hurting the motor. In a carb motor if the fuel runs away from the pick-up you have a reserve in the float bowl until the pump picks it back up. The EFI system isn't that way, it needs constant flow. My set up has a low pressure pump supply the reservoir tank from one or the other side tanks. The high pressure pump pulls from and returns to the reservoir tank. I'm just paranoid and overbuild stuff, but that's my two cents.
I hope others chime in with other ideas for you too.

 

[Cdog]

Thx for your reply. I’m trying not to over think it, but it seems complicated.

Packaging is important because I don’t have a lot of space to work with.

I was thinking I could run a equalizing hose between the tanks. All this under the floor between the two floor lockers. Once the return fills one tank about 2/3 it will have a way to over flow to the other side.

I haven’t had the floor up yet so I don’t know For sure what’s under there. I believe the boat has 4 full length stringers and the two existing fiberglass tanks are between the two on each side. Is it a bad idea to put a 1.5 inch hole in 2 of the 4 stringers mid boat?

Holley makes these new mat type pickups that seem to work really well. Does anyone use these in marine applications yet?

 

[Jonas Grumby]

Like this , I have 2 blowers, so the return for each feed into both sides of the regulator, then a single line to the fuel switch. Each side of that imco superswitch is a in and a out to the tanks.

 

[Cdog]

Got it! Just found the $700 answer!! Haha! Thx guys!

http://www.imcomarine.com/cal_store/fuel-tanks/fuel-valves/6-port-superfuel-valve.html

 

[Jonas Grumby]

Got it! Just found the $700 answer!! Haha! Thx guys!

http://www.imcomarine.com/cal_store/fuel-tanks/fuel-valves/6-port-superfuel-valve.html

Yup, that’s the bitch you need, it took me a whole day to figure out the layout before drilling holes, I really don’t like it on its side, but that bitch is big and takes up space, after I did it, I have seen many builders do the same thing.

 

[Cdog]

Yup, that’s the bitch you need, it took me a whole day to figure out the layout before drilling holes, I really don’t like it on its side, but that bitch is big and takes up space, after I did it, I have seen many builders do the same thing.

I’ve seen these before but never inquired what they were for. Funny it came to mind as you were making your reply.

Thx for the help.

Cheers!

 

[BamBam]

I’ve seen these before but never inquired what they were for. Funny it came to mind as you were making your reply.

Thx for the help.

Cheers!

As noted in Option 1 of my post. I just didn't have the specifics. Sounds like you have a fun project enjoy

 

[Cdog]

Do any of you guys bother with a water separater on a river boat? It seems like it will be a bottle neck in the fuel system. On my last set up I ran a filter

 

[Jonas Grumby]

The filter you see in my pic is a water separator

 

[02HoWaRd26]

Could run a dual inlet fuel filter, one inlet from the fuel valve/tanks then the out to the pump, pump to fuel cooler, cooler to fuel rail, fuel rail to regulator, regulator to the other Inlet on filter housing. Makes a real nice easy circle and makes sure you never lose prime or pressure, well unless you run out of fuel that is!!!

 

[02HoWaRd26]

This filter head is what you need. You just cap one of the inlets.

 

[Cdog]

This filter head is what you need. You just cap one of the inlets. View attachment 660061

Thx!

 

[LargeOrangeFont]

Am I assuming correctly that the 6 port fuel valve is needed because of your need for a return line?

I just ask because I have the 3 port switch on my boat, but have the stock Mercuriser fuel injection setup.

 

[Cdog]

Am I assuming correctly that the 6 port fuel valve is needed because of your need for a return line?

I just ask because I have the 3 port switch on my boat, but have the stock Mercuriser fuel injection setup.

Right. In order to keep the pump cool on aftermarket external pumps you have to run a return line.

02Howard26 came up with a plumbing trick where you can use a 4 port filter head and plumb the return back through the filter instead of back to the tank. This way would eliminate the need for the IMCO switch.

 

[LargeOrangeFont]

Right. In order to keep the pump cool on aftermarket external pumps you have to run a return line.

02Howard26 came up with a plumbing trick where you can use a 4 port filter head and plumb the return back through the filter instead of back to the tank. This way would eliminate the need for the IMCO switch.

Yea, makes total sense. Yea I could envision a few ways to get around the switch, or at least just use the 3 port version if you still wanted to remote switch between 2 tanks.

 

[Cdog]

Yea, makes total sense. Yea I could envision a few ways to get around the switch, or at least just use the 3 port version if you still wanted to remote switch between 2 tanks.

I do have a switch currently but it only allows between tanks. It won’t control which tank gets the return. Options are to run the loop through a 4 port filter or get a second switch that is operated in unison with the tank selector switch. Or upgrade to the 6 port IMCO unit. Still might be the better option. I need to call Aeromotive and find out if the filter loop will keep the pump cool enough.

 

[Jonas Grumby]

Just remember if you decide to “T” it back in, you need to cool it,,,I’m told. And fwiw Bob teague told me to step up to the plate and get the superswitch. It’s the right way to do it. Don’t shoot the messenger.

 

[Cdog]

Just remember if you decide to “T” it back in, you need to cool it,,,I’m told. And fwiw Bob teague told me to step up to the plate and get the superswitch. It’s the right way to do it. Don’t shoot the messenger.

Cool it before it goes back into filter head?

Before & after?

 

[02HoWaRd26]

Cool it before it goes back into filter head?

Before & after?

Yea that actually makes a lot of sense as the return fuel will always be the hottest fuel, so could easily run a small fuel cooler pre-fuel rail, and use the larger on the return route of the fuel line.

 

[Jonas Grumby]

Cool it before it goes back into filter head?

Before & after?

Yes, before, and I might just have 2 of them here at the house
Edit: looks like only one of them made the move.

 

[Cdog]

Yes, before, and I might just have 2 of them here at the house

LMK I’m interested.

 

[Jonas Grumby]

LMK I’m interested.

It’s in Havasu, You gimme what you think it’s worth.
I’m here through Sunday unless something changes.
-10 AN