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Wags38

Help with Carburetor Tuning - Eddlebrock 1409

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Wags38

I recently replaced my carb from the OEM webber to a new Eddlebrock 1409. The engine runs great, but only when there are two people in the boat. As soon as there are 4-6 people it struggles to get on plane. The boat is 96' Euro F3, with 350 Mag Tournament Skier.

It does not sound like my secondary butterfly valves are opening. The other day looking at the carb with the flame arrestor off, i manually operated the throttle linkage and witnessed the secondary open and the engine roar like i haven't heard it do since changing the carb.

My question is does any one have experience with tuning these carburetors? reading through the manual, there are ways to tune the acerb, but it is in mechanic jargon and I don't know what direction to tune it so that it will help with this specific engine.

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Woodski

@Wags38: What was the reason you swapped carbs? They are pretty much the same carb, so you should be able to get the new one to work well for you. I have tuned my Weber although I have not had the issue you are describing. It does sound as if the secondaries are not opening and could be for a variety of reasons:

1. It should be mechanical, but is there a vacuum line you did not install or changed when you swapped carbs? Some are vacuum operated secondaries.

2. It sounds like either the linkage is locked or bound up for some reason or not connected properly, if the boat surged particularly with a PP unit, many people disconnected the secondaries.

3. This carb has an air valve, it is a weighted butterfly that swings open via air flow and vacuum, check to see if it is free. Is this what you saw opening, it is above the secondary throttle plates (butterflies)

It has been a while since I had to tinker with the carb, so I would need to go back and look at what might be causing the issue. There is a lot of good material on that carb, google either Edelbrock and certainly google Carter AFB which is the same carb. Less info if you try Weber 4 bbl.

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MadMan

There is always a problem with direct drives and carburetors. The engine is angled back and then when you are coming on plane this angle gets worse. The problem is, if the fuel level, in the float bowls, gets higher than the rear booster venturi, gas just drips out of them instead of being drawn out by vacuum. This leads to a supper rich condition.

You could try lowering the float levels or install an angled wedge under the carb.

http://www.themalibucrew.com/forums/index.php?/topic/56751-fuel-starvation-when-adding-ballast-to-carbureted-malibu/

Edited by MadMan

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Wayne

After checking what Woodski pointed out, the tension on the secondary air flap may be too high. Here is a YouTube video on how to adjust it. This assumes everything else is ok.

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Wags38

Thanks for the quick feedback guys. @Wayne, I saw this video. Unfortunately my carb does not have this adjustment screw.

I truly believe that i am just not getting enough vacuum to open the air valves. I looked at my throttle cable and i have the full range of motion on the linkage, so i was hoping that i could tune it and somehow increase the vacuum.

I found the tuning kit on amazon and my owners manual has directions on tuning the carb, I am just struggling on what direction to tune. They give you lean or rich directions, and the springs/jets/rods to make the adjustments. I was hoping that i could get someone to put it into layman's terms for me.

@madman - Your point makes sense. I will have to go check this condition see if that is happening.

@woodski - i changed the carb because i jumped the gun a bit. i was having issues, i thought it was the carb, turned out to be old ignition system. Fixed the ignition, now having carb issues. The secondary on this carb are vacuum controlled.

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MadMan

You're right, that carb does not have a spring to adjust the timing of the secondary opening (you have an AFB, not an AVS). It is controlled by a counter-weight. You can adjust it by grinding away the counter-weight or welding material to it. I've had limited success (on a car) doing this. But I don't think this is your issue.

Edited by MadMan

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Wayne

Is it too late to return that carburetor? I've sent back ones I've run that just didn't work but it depends on where you have purchased it from.

I'm of the opinion that this one just does not have the adjustments you need or is not the right fit for your use. I could very well be wrong as I have never had luck with anything but Holley, so I have a personal bias and wanted to disclose it.

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Woodski

@wags38: from your last comment, I would give the Weber another shot.

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Wags38

Guys, while i appreciate the feedback, its not what I was looking for. I asked if someone could help with tuning the carburetor I currently have. Its was not to debate Holley vs Eddlebrock, or take it back to stock. Simply help tuning the Eddlebrock Carb I already bought and have installed on my boat.

If anyone can help with tuning the 1409, please let me know.

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MadMan

Guys, while i appreciate the feedback, its not what I was looking for. I asked if someone could help with tuning the carburetor I currently have. Its was not to debate Holley vs Eddlebrock, or take it back to stock. Simply help tuning the Eddlebrock Carb I already bought and have installed on my boat.

If anyone can help with tuning the 1409, please let me know.

I would say the factory calibration of your carb is not the problem, it may not be optimized, but you would only see a small improvement by tuning it. It should run pretty well just the way it came.

Now there could be something actually wrong with the carb, or an install problem.

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justgary

On the needles, generally you will screw them in for leaner and out for richer. Is this the kind of help you are looking for?

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