efi swap, is it worth it?

fishingman220

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Jun 13, 2008
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568
what is the easiest way on a 96 5.7 merc to swap over to efi??? my motor already has late model center bolt heads. is there any way to take everything off a car or truck, maybe a throttle body set up off a early 90s pick up. could you do that and then just put a flame arrestor on top? i am just really starting to hate messing with this carb and dont have the money to go out and buy a new efi setup.
 

danond

Lieutenant Junior Grade
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Jun 11, 2007
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1,118
Re: efi swap, is it worth it?

Why are you having to mess with your carb? I have an '89 and it starts with a key twitch, idles better than my '02 Chevy pickup.
 

Reel Poor

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Jan 29, 2005
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5,522
Re: efi swap, is it worth it?

In a word......No. Those automotive systems are not USCG approved, are not water proof, are not set up to run under the same type loads as marine engines, and they require a fuel return line to the fuel tank which is not legal in the marine applications. There's probably more but that should answer your question.
 

Mkos1980

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Oct 25, 2007
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Re: efi swap, is it worth it?

Stick with the carb. It would be too much $$ to swap over unless you got a take off unit from a blown motor or something. I upgraded to the Edelbrock Marine carb and with the first poster, mine also fires right up idles silky smooth and I have no hesitation or anything with it. Its almost like having EFI with this carb.
 

TilliamWe

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Dec 21, 2004
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Re: efi swap, is it worth it?

While I don't agree with all Reel Poor's assertions (GM TBI from a truck is EXACTLY the same as what is on a boat), he is right. No it isn't worth it. Besides not having the magic "Marine" rating, TBI will not create any more power than a well tuned carb. And besides, what computer are you going to get to run it?
Quit "messing around" with the carb, maybe that will make it better?
 

AZSenza

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Mar 11, 2008
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521
Re: efi swap, is it worth it?

I agree with the above, not worth the money. You'd have to pop for a holley or edelbrock marine setup to get the right wiring harness and computer. As for the TBI unit, its not the same. as with all (that I have seen) marine fuel units, there are no vaccum provisions...Look closely and you will see. My advice...buy a new Edelbrock 600 marine carb, install it, set the idle and leave it alone...they are that good out of the box.
 

Tail_Gunner

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Jan 13, 2006
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6,237
Re: efi swap, is it worth it?

:D I may just be in a postion lend you a hand if you decide to go that way...I know of a person who has a complete TBI system 80 hours on it works fine and complete...Psst its off a volvo 4.3..fuel cell and the whole shootn match..is factory marine certifired all of it.
 

danond

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Jun 11, 2007
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1,118
Re: efi swap, is it worth it?

...and dont have the money to go out and buy a new efi setup.

If you're short on cash, converting to EFI is not cheap, no matter where you source the parts, and you will likely be screwing around with that setup WAY more than a well tuned, rebuilt, cleaned up carb.

Rebuild the carburetor, or have someone else do it, then give the motor a tune-up.
 

fishingman220

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Jun 13, 2008
Messages
568
Re: efi swap, is it worth it?

well thanks for all the advice, i have put new plugs, wires, cap and rotor. i just got the carb back from being rebuilt, and i guess i will see how that works out. i have a 2bbl mercarb. what would be the cheapest way to go 4bbl? i have a eldebrock 650, but its not marine, does it matter??
 

meesh

Petty Officer 1st Class
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Aug 24, 2008
Messages
256
Re: efi swap, is it worth it?

Yes it matters, you cant use a non marine carb. If you want to go with a 4 barrel, Edelbrocks 1409 600 cfm is great, right out of the box. I run edelbrocks on my trucks and my boat and they really have solved my carb problems.
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: efi swap, is it worth it?

Nick - Do yourself a favor and never look at that page again.

There are multiple SERIOUS flaw in that "design" that could end in BOOM
Return line to fuel tank, no supervisory circuit on the fuel pump, no overflow from pump to carb(TBI in this case), is it even a marine pump, either one?

etc, etc, etc.

All of that effort to create an unsafe boat, just so he wouldn't have to rebuild a carb.......

Definately inline to head up Obama's new marine rejuvination task force....
 

fishingman220

Chief Petty Officer
Joined
Jun 13, 2008
Messages
568
Re: efi swap, is it worth it?

ok thanks, hopefully the mercarb will work out, i will let you know, thank you again
 

cheburashka

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Joined
May 28, 2005
Messages
715
Re: efi swap, is it worth it?

Definately inline to head up Obama's new marine rejuvination task force....


Hey--I kept politics out of these threads for eight years while I was completely irritated with the administration. How 'bout you do the same?


I like the way the guy on that site now has his engine set up to rev to almost double what it originally revved to. Apparently, he gave no thought whatsoever about what that does to the outdrive.
 
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