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Possible to have too much vaccum?

614 Views 11 Replies 7 Participants Last post by  BillDini
Trying to learn about carbs so bought an vacuum gauge to adjust the idle mixture ratio. Here is what I am getting at idle. Any ideas or is this reading ok? Gauge is from Harbor Freight so maybe it is bad?


Engine fully warm, idle set to 800-850 rpm. Gauge hooked to small port underneath in front of carb. Engine (from what I am told) is a ZZ4 shortblock with Edelbrock RPM heads, intake, and assume the matching cam. Carb is Holley Street Avenger 670. Mixture screws are 1 full turn out.

Engine runs good and doesn't seem like there are any issues. Just checking things out, learning, and tinkering with it.

Motor vehicle Watch Gauge Speedometer Measuring instrument
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Looks like about 22 inches of vacuum. Someone else may have another opinion, but I'd leave it alone. Don't create a problem where you don't have one.
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