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Rochester, need some help

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Old 07-04-2018, 02:04 PM
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Claudio Silvreti
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Default Rochester, need some help

Hi, have a problem with my Rochester 4 barrel carburetor. A bit too much gasoline. Should I turn the idle Mixture Screws a quarter in or turn out to be less fuel? Thanks for your help.
Old 07-04-2018, 02:50 PM
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JayRay
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When you turn the mixture screws hook a vacuum gage up to one of the vacuum ports, from what I understand you twist it until the vacuum reaches its highest reading, then do the same to the other side. Should max out in the high teens low 20’s range. Mine maxed at 21”.

someone with more experience will probably chime in.
Old 07-04-2018, 03:17 PM
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RonR80
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Yes turn them in it will lean out , make sure you have no other issues,vaccum hoses, loose carb bolts,
Old 07-06-2018, 07:16 PM
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lars
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Originally Posted by Claudio Silvreti
Hi, have a problem with my Rochester 4 barrel carburetor. A bit too much gasoline. Should I turn the idle Mixture Screws a quarter in or turn out to be less fuel? Thanks for your help.
If you have a problem so severe that you have "too much gasoline," you have problems much more significant than a mixture screw adjustment issue. You can run the mixture screws "full rich" on any Rochester without noticeable drivability issues. If you have verified that you actually are running rich ("90% of all carb issues are timing issues"), you need to tear the carb down to determine the real problem.

Lars

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