Thread: New 496 wont run??

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With only 6hg vacuum, I would be suspicious of the power valve opening and flooding, another reason I suggested closing the the idle mixture screws.

Also, a single backfire can destroy the power valve (I seem to recall this is especially true for Holley, and anti backfire kits are available)

Originally Posted by 36 sedan

With only 6hg vacuum, I would be suspicious of the power valve opening and flooding, another reason I suggested closing the the idle mixture screws.

Din Ding Ding..... we have a winner! Run the carb dry and pull the metering plate(s) to see what number is on the power valve. It sounds like fuel is dripping past with that low vacuum signal. Perhaps the paperwork can give you the value too??? Or ask the OEM what they put in'em from the factory.