Thread: Terrible milage
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Old June 16th, 2022, 05:37 PM
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Default Re: Terrible milage

this is a holly 2300 carb we are talking about. the power valve is located on the the plate that the jets screw into. it is basically a needle valve with a vacuum diaphram on the end of it. the numbers on the valve refer to the number of inches of vacuum it takes to move the diaphram and open the needle which allows more fuel to flow into the engine, for enrichment when accelerating. the lowest number i have seen is 2 and the highest number i have seen is 7. the # 7 valve will open sooner than the 2 valve, vacuum drops when the throttle plate is opened. high vacuum at idle, no vacuum at wide open throttle.
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