Need Carb Help

My boss has an '87 F250 with a 460 CI V8 and Holley 4 bbl carb. The engine is completely stock. A couple of yeras ago he purchased a new carb from the
Ford dealer and had someone install it. The truck runs fine. Problem is when he hooks up his horse trailer the engine begins to sputter when going up hill. It only does it when pulling a trailer.
Here is my theory. With the additional load the truck is burning more fuel which empties the float bowls faster. That, combined with an angle starves the engine of fuel. I think he needs to raise his float to cure the problem.
What do y'all think and have you seen this problem before?
Thanks in a advance...
Casey Teague http://justjeeps.jeepz.com
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I think raising the float will delay the on-set of the problem for maybe a few seconds. Better fuel *supply* would probably help.
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snipped-for-privacy@sbcglobal.net says...

That's a good guess. Loading it up also puts the carb running continuously at a different place on the needle than it normally does. Might need to change the needle to fatten up the midrange. It depends on how the problem comes about.
Is it sputtering as soon as he gets on the gas, or does it take 5-10 seconds and then does it continuously till he lets off the gas? If the latter, it's fuel flow, either pump or filter or kinked fuel line.
Might want to check the timing, too. Move it a couple degrees if it's dead on to see if it has any affect, better or worse. If it's worse, move it the other way. Is it backfiring, or just missing?
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Holley has a website with some excellent info on it, including the settings for nearly all of their carbs. Your problem could be the initial opening of the secondaries being too large, creating a bog, too little fuel delivery, or improper jets, to name just a few. Raising the fuel level is probably not the problem if it runs well otherwise. Too high a fuel level can create an overrich idle. Open the plugs on the sides of the carb to the fuel bowls. Proper level is JUST below these. (Raise level till fuel comes out, then back off a hair.) If the truck has a smooth idle, this is easy. If it idles rough, this can be difficult. If the fuel problem turns out to be what you suspect, Different fuel bowls with centerhung floats are available for some carbs. These are usually only needed for racing aplications, where extremely hard cornering leads to fuel starvation.
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On Wed, 8 Oct 2003 05:16:53 -0500, "Casey Teague"

I would start with a new fuel filter. That failing, It would be in order to temporarily install a fuel pressure guage to be sure it is maintaining good pressure under load. A weak fuel pump or partially clogged filter will work great - under light loads.
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Thanks all for the response. For the question regarding when it begins to miss it happens 5 to 10 seconds into the hill. Then, if there is another hill it begins imediately.
We will try the fuel filter and check for kinks in the line. May need to invest in a fuel pressure gauge to see what that looks like too.
Thanks again for all responses. Gives us a good place to look.
Casey Teague http://justjeeps.jeepz.com

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starves
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