Winter to-do list and Fuel injection kits?

[KantishnaCabin]

So, I'm considering my winter projects and upgrades for my boat. I have a 1994 Jetcraft with a 5.7L Kodiak 3 stage pump. On the list for this year already is a stomp grate and impeller rebuild. The stomp grate is a no-brainer, this year I used my PWC winch for the first time to clear a errant willow bush from my intake. Lets just say that I was exploring areas that have not been previously available due to the very high water in early September. That willow bush had it coming, but I think I lost the argument.
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The rebuild on the impellers is also something fairly high on my to-do list. My current setup isn't to bad at the moment but I'd really like to go with an overlap first stage and rebuild the 2nd and 3rd. My sleeves are pretty good, 3rd stage sleeve is new this year and I changed both cutlass bearings when I did the sleeve for the 3rd stage.

My real quandary is regarding fuel injection kits. I'm considering making the upgrade. Has anyone here done this yet?

ttps://www.affordable-fuel-injection.com/product/chevrolet-marine-complete-tbi-system/
https://www.youtube.com/watch?v=MzRJh6kp6HY

It looks pretty straight forward, but if anyone here has done this I'd like to know what you thought.

[Rob B]

Check out the Fitech 600. I had one on a 454 BBC in a car I was building and it's very simple to get set up. It might still be one of the cheapest complete kits around. Definitely worth looking at.

[Daveinthebush]

Rob; I have a 7.4 with a Holley four barrel. I like the idea of converting to EFI. Did you get better mpg and or gph?

[Rob B]

Actually it ran great before I had other issues pop up. I ended up tearing the motor down and replacing some
Internal parts. In the mean time I sold the EFI and went with a Holley 950. I wish i had the Fitech EFI back now. Those cold morning instant start ups sure were nice.


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[KantishnaCabin]

Man, this is going to be a tough decision. A mechanic friend of mine is really recommending a MPFI system over the TBI.

https://www.edelbrock.com/pro-flo-4-...ads-35780.html

Something like this I guess. I'm having a hard time finding a conversion MPFI kit specifically for marine application though. The real problem seems to be the O2 sensor placement in a wet exhaust. Although Performance EFI sells in their kit a spacer that goes between the manifold and riser that has a sensor bung in it.

Anyhow, I think I can piece a MPFI package together, however is it really worth the extra cost? Performance EFI has an entire TBI kit including O2 sensor spacer and electric fuel pump for roughly $1,000. The cheapest MPFI kit I can find is the Edelbrock Pro-flow 4 for $1,850 but it doesn't include a HP fuel pump or the O2 sensor spacer plate. So really its probably closer to $2,500.

Is the performance gain for MPFI over TBI worth the extra $1,500? Not sure it is, personally.

[Akgramps]

I have wondered this same thing for a 5.7 in 24' boat, however the O2 sensor is one thing to work around and there will likely be others. If I bought a new motor I would want FI, but not sure if its work foolin with on a existing.

My conclusion.........for what its worth..... A boat motor is akin to a stationary power plant, running at 75/80% throttle most of the time. Its pretty easy to tune a carb to run under those conditions, Where FI really shines is in a variety of throttle positions, pulling hills, towing....cold starts... It sure would be nice to know if a guy could get XX mileage improvement... I vote you try it and let us know............!

[KantishnaCabin]

Haha, I think I,m going to try it. Probably sometime in the spring. I will post the project here as much as I can. I think I found a O2 sensor solution that seems affordable.
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The adapter insert that Performance Fuel Injection service sells won’t fit my Kodak riser. It is made for Mercruiser risers and they just don’t line up right. Anyways, I’m still debating the cost difference between MPFI and TBI. The rest of it looks doable.

[Akgramps]

Now you got me going on this.... here is some food for thought,
https://www.efisystempro.com/efi-pro...engines-to-efi

[KantishnaCabin]

That’s the site I found the link to the O2 sensor adapter kit for the riser on. There is a link to a company that does headers too that will add 30ish HP but I would worry about the heat in my engine compartment I think.