Holley Carb Fuel Problem - Team Camaro Tech
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post #1 of 6 (permalink) Old Jun 30th, 09, 12:10 PM Thread Starter
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Chuck
 
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Holley Carb Fuel Problem



I have a holley carb (750 DP Holley) similar to the attached pic on my 396 camaro and it runs fine for about 20 seconds at idle until fuel gushes from the circled part. No fuel comes from the back two, but is it supposed to only get fuel from the front rings. The jets work fine on the front and back also.

The car drives fine, until I come to a stop then I have to rev it up to keep it going. Thanks
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post #2 of 6 (permalink) Old Jun 30th, 09, 12:18 PM
DjD
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Re: Holley Carb Fuel Problem

It sounds like the needle and seat on the front bowl has dirt in it or the floats are too high on the front bowl. What version of this carb do you have? Look on the side for the numbers. The one you show in the picture is a mechanical secondary (double pumper) which I believe is a 4 corner idle, meaning the carb idles on all 4 barrels. They make a vacuum secondary version of this carb with both 4 corner and just primary side idle, the numbers on the side will tell us what you have...

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post #3 of 6 (permalink) Old Jun 30th, 09, 12:25 PM Thread Starter
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Re: Holley Carb Fuel Problem

I will take a look tomorrow and post the numbers. It does have adj screws on all four corners.
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post #4 of 6 (permalink) Old Jun 30th, 09, 05:01 PM
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Re: Holley Carb Fuel Problem

Too high fuel pressure will lift the needle off it's seat and flood the carb as well. 5psi is typical with 7psi being high.

Have you set the float level? There are plugs on the sides of the carb and the float should be adjusted so fuel just begins to tricle out the plug. The plugs are typically brass, about 1/4" in diameter and require a large flat blade screwdriver to remove. They also have a little gasket on them. They make clear plastic bowl plugs so you can see the level with the engine running allowing you time to adjust the float level on the fly. Just don't leave the plugs in if you use them - there have been several folks who had them melt presumably from ethanol in the gas creating a fire hazard.

Just don't do this when the motor is hot such that a fuel fire could develop.

Dave
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post #5 of 6 (permalink) Old Jul 1st, 09, 09:08 AM Thread Starter
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Chuck
 
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Re: Holley Carb Fuel Problem

Quote:
Originally Posted by dnult View Post
Too high fuel pressure will lift the needle off it's seat and flood the carb as well. 5psi is typical with 7psi being high.

Have you set the float level? There are plugs on the sides of the carb and the float should be adjusted so fuel just begins to tricle out the plug. The plugs are typically brass, about 1/4" in diameter and require a large flat blade screwdriver to remove. They also have a little gasket on them. They make clear plastic bowl plugs so you can see the level with the engine running allowing you time to adjust the float level on the fly. Just don't leave the plugs in if you use them - there have been several folks who had them melt presumably from ethanol in the gas creating a fire hazard.

Just don't do this when the motor is hot such that a fuel fire could develop.
psi is at 4 1/2 according to the gauge. I just took apart the carb and cleaned it all up, but we will see when I put it back on if it still has the same problem. The floats all work fine and didn't see any blockage.
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post #6 of 6 (permalink) Old Jul 2nd, 09, 02:25 AM Thread Starter
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Re: Holley Carb Fuel Problem

It's working fine for now and thanks for your input. I ordered the bowl viewing plugs too....

thanks
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