The boat has been doing this since I bought it in May.

Runs great on the trailer. Starts fine at the launch ramp. Launch the boat, starts fine, and then stalls and doesn't want to restart.

If after time it restarts then it's normally fine. If it doesn't, then I get to go home.

Today at the TPM it did this exact thing. Except now it won't run on the trailer either.

Got it home and started playing with it. I figure the floats are off and causing issues when the boat is in the water. I checked the floats and both measurements were out of spec, so I set them per the manual.

I notice my fuel pressure is building up to 10-12 on the gauge and I can see any fuel getting into the carb. I undid the fuel line to the carb and it shot fuel all over. Also replaced the water separator and it has a new fuel filter. I know there's a ton of fuel trying to get in.

If I pour fuel down the throat the boat will run on that, but that's it.

The carb is a 750 street carb, mechanical secondaries and electric choke.

Floats set per spec. All four jets in the body are clear. Needles move fine. Fuel bowls were clean with no junk in them.

I figure there's a passage clogged somewhere. Any ideas on what to look for?

Unfortunately one of the little torx head screws for the needle cover snapped, so I have to get an easy out tomorrow.






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Well if I were u throw that carb away get a holly . Also check ur timing


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X2 on the Holley


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Thanks GT. I had the pins out to adjust the float droop. Wish I would have dug a little deeper.

I'll check those passages.

Right now, money is going into desert season, so a carb rebuild is much more likely than a carb swap.


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When you get the fuel flowing, double check your fuel pressure.  The AFB type carb doesn't like much pressure (about 6psi max).

It normally fluctuates between 5.5-6.5 when running. Will make sure it's still there once it's going again.


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I'm not the biggest fan of these carbs for performance applications but on a mild motor they actually work pretty good. Remove the filters as stated before. Turn the mixture screws in until they seat counting how many turns it takes. Then remove them and clean the tips with some scotch bright. You don't have to get crazy. Just get them clean and re install. A full rebuild of the carb is probably in order but you can try these things first.


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While I wont go out on a limb and say that these are the best carburetors on the planet, for engines producing up to about 450 HP, they work excellent. You just have to know how to dial them in and what their idiosyncrasies are.

Mercruiser actually used them on the 330 HP 454 for several years with very few issues.

The main issue is that the design started out as a Carter AFB, Weber bought it, tweaked it a little, then Edelbrock bought it and tweaked it again.

The Carter Strip kit still fits several things on the newest version... On a boat, the accelerator pump linkage needs to be on the shortest hole and the metering rods typically need to drop by two sizes to work right under the low vacuum conditions of most jets...

Here is a great resource.

http://www.thecarburetorshop.com/AFBtuningtips.htm

My off road buddys like these carburetors for their stability on rough terrain... You can damn near turn them upside down and they will still run, a Holley on the other hand, not so much.

GT

You have come this far might as well rebuild it. Go buy a gallon of carb dip and the rebuilt kit from any auto parts store. Tear it all down, soak everything for a few hours, rinse it clean, blow dry, and reassemble. This will insure everything is clean and correct. It is a bit overwhelming the first time you do it but if you take your time and pay attention you won't have any problems.


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Sounds good. Remember to do your idle adjustments after a few passes that way the motor is warm and running most efficient. Then you can make compromise adjustments later to help with cold starting.


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Do you have a pcv valve on that thing ?  Fords like to have the correct pcv valve or you get a vacuum leak.

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Sounds like a vacuum leak. Check the base of the carb to the intake.  My brother had a plate between the carb and intake and was doing the same thing.  Removed the plate and went to a different style issue went away.  Hope that helps a little.


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Pulled the carb apart again and blew out all the passages.

Replaced the PCV valve with one recommended for a 460. Ran new vacuum hose to the front port on the carb and blocked off the rear port. They should be the same vacuum, but Edelbrock said use the front.

Adjusted the choke.

Will adjust the idle air/fuel screws with a vacuum gauge Saturday. 

Hopefully I'll get out to Elsinore Saturday or Sunday and see if I've finally sorted it out.

In Edelbrock's manual they state "DO NOT allow the vehicle air-stream to blow across the top of the carburetor such as on an open-bodied car or full bodied vehicle with tunnel-ram manifold. The flow of air across the carburetor will result in an upset to the fuel metering that cannot be accommodated by recalibration since the change to the A/F ratio will be different for every vehicle speed."

My scoop faces forward, since the jet splashes at idle and I don't want to suck water. Guess I'll try facing it backwards, but I can't imagine that it would make that big of a difference with a flame arrest or in there.


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The venturi effect is common on all carburetors, not specific to Edlebrock...

The scoop should negate any issues no matter which way it faces... 

GT

Easiest fix is to remove the Edelbrick , place it behind the tire of the trailer so the trailer don't roll and install anything else.....
I hate those Edeljunk carbs with a deep rooted passion.

-beerjet-

Think I may have found an issue with the 12 volt supply to the electric choke on my Edelbrock.

If the choke were to lose 12v would the ambient temperature from the engine keep the choke off, or would it close down again; would the choke again be on?






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Thanks! I corrected the wire, but was curious what, if any, effect it would have.

Got all the water out if the system and the boat ran all right on Saturday. Wouldn't idle coming into the marina after running fine all day. I'm pretty sure it was water from the spray getting into the flame arrestor and carb. The wind picked up and it was a very wet ride back across the lake.

Will turn the air cleaner around after cleaning out the carb again and hope for the best at Parker next weekend.


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