How do I convert my carburated 351 to fuel injection?

[rman56]

Iam very interested in the FAST too. I talked to them a year ago but still thinking on it. I had my carb rebuilt last spring it works ok for a carb. I talked to alot of people and they thought a carb should idle at 800rpm but no way on my boat it loads up big time. The best I can get it is 1000rpm and 900 in gear and works good but if a guy can get injection to work good thats the way to go!

[swc5150]

I think by the time you incur the costs involved in adding an EFI system, you could've sold your boat and tracked down a nice EFI equipped SN for not a heck of a lot more money.

[TRBenj]

A stock 351 should idle like a sewing machine down to 600rpm (or lower if damper knock weren't a concern). If you can't get it to idle below 1000 then something is very, very wrong.

It amazes me that the people who can't tune a dirt simple carb properly think they can install a one-off efi retrofit kit and get it to run well. :-p

[rman56]

Thats what I thought, we adjusted the idle mixture screws and had it working really well idled low. Then a few pulls later it seemed out of wack again. So it might come off this winter and may go through it again, might be a little something we over looked.

[AirTool]

A stock 351 should idle like a sewing machine down to 600rpm

exactly

[Zach@n3]

My boat idles at 400 in gear with the nose bunked in the trailer. 600 in gear underway. Doesn't matter how hot or cold it is out starts up the same.

Listen to Tim. You need to figure out why it does what it does before you go blowing alot of cash. If the engine has a problem thats not carb related you will still see it with the fuel injection system.

These boats ran just like fuel injected boats when they were new there is no reason they shouldn't now.

[DW SD]

I converted my first Correct Craft, a '77 Ski Tique, to a Holley Projection system (very early Throttle body EFI conversion) back in the late nineties. The system didn't use any O2 sensor for closed loop operation. It just had a few knobs for tuning: low, mid and high rpm rich / lean and I think an accelerator pump setting. Once the conversion was done my engine never ran or started better. I used the smaller 2-barrel Projection system to replace a 4bbl 450 CFM holley on an old 302.

The thing I don't like about carburetors on boats, unless you run them every day or nearly each day, (like you might a daily driver car), the carburetor gaskets tend to dry out, the fuel in the bowls evaporate leaving varnish to plug jets and orifices and the float bowl eventually valves get stuck open, etc. They are just a pain. You almost need to proactively rebuild them each year from my experience. I'm a big believer in fuel injection for boats that see sporadic use. I admit, I didn't ever use an additive to properly stabilize the fuel, though.

I didn't know the FAST system could be used at least with their self-tuning mode and a wide-band O2 sensor. I had thought the sensor wouldn't be compatible with the water in the exhaust. Or perhaps they are added upstream of the risers?

[Tryathlete]

I wonder what it would take to put a GT-40 from a mid-90's Nautique in an older boat. Seems like for all the trouble, it might just make sense to buy a newer boat.


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[Fast351]

Something's wrong with the engine. The leaking fuel thing is a very common problem. This is a gasket issue between the metering block and the carb body. Also check for vacuum leaks. A boat that runs great at higher RPMs but will not idle is a telltale sign of a vacuum leak. Use carb spray to diagnose. The RPMs will increase when you hit the vacuum leak with carb spray.

As for fuel injection, sure, you COULD swap it, but if the underlying problem is a vacuum leak somewhere, and you don't fix it, the FI system will have the same issue.

Holley carb setups are so simple that it's hard to believe that you can't solve the problem with a little work. Not sure if the exact carb is still available but worst case you need to replace it because of a porous casting.

[lucky7t]

Hello all my "2001" nautique lovers! Im thinking about converting my 84 stock 351 to fuel injection. How big of a pain is this process and where do I start? Is it as simple as the manifold, injectors, and air assembly? Does it require some sort of OEM computer or something? What would a ballpark figure for the parts run me? Any info or opinions would be very much appreciated!!!

Thank You

KYancy

We are a FAST dealer and if you do buy the FAST Ez-Efi system please make sure you buy the 2.0.

[a0128]

You all realize you are responding to a FOUR YEAR OLD POST. LOL.