Mixture Screw Operation
2026 Loser of the Year
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From: New Or-leens Loo-z-anna
FYI.."........One of my mixture screws didn't affect the idle.....I took the top off the carb and used air pressure and a wire to force the trah out....it adjusted correctly after cleaning.
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Melting Slicks
Joined: Oct 2013
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From: San Diego California
2026 Loser of the Year
Joined: Sep 2013
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From: New Or-leens Loo-z-anna
The passenger's side screw worked correctly....so I took the top off the carb/removed THAT mixture screw and used a rubbertipped air nozzle to blow 50psi air into the screw opening/located the air-exits in the carb by feeling each tiny hole in the internal area of the carb.
Then I removed the mixture screw from the "bad" idle circuit/blew air in with no results---no air exited through the identical holes on that side of the carb---I found a wire the correct diameter that would fit into the clogged exit holes and slowly fed the wire in---tiny pieces of sand/trash came out of the idle mixture screw-hole....I used more air pressure and the wire again until there was good airflow in both directions.
Reassembled and adjusted carb/worked great/idled great.
Then I removed the mixture screw from the "bad" idle circuit/blew air in with no results---no air exited through the identical holes on that side of the carb---I found a wire the correct diameter that would fit into the clogged exit holes and slowly fed the wire in---tiny pieces of sand/trash came out of the idle mixture screw-hole....I used more air pressure and the wire again until there was good airflow in both directions.
Reassembled and adjusted carb/worked great/idled great.
Team Owner
Joined: Jan 2006
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From: Crossville TN
Make sure the fuel filter in the carb (or in the fuel line) is still good and doing its job. No way for that kind of stuff to get in there, unless the fuel filter is clogged/damaged or not there.
Good catch!!
Good catch!!
2026 Loser of the Year
Joined: Sep 2013
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From: New Or-leens Loo-z-anna
VERY TRUE about filters!
An inline filter right before the fuel pump will spare the pump AND the carb! One at or in the carb won't hurt either
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Melting Slicks
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From: San Diego California
Any examples out there?
Steve
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From: mount holly NC
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On a Q-jet there should be a filter where the hard line from the pump connects to the carburetor.
There is a long or a short filter so get the correct one.
There is a long or a short filter so get the correct one.
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Melting Slicks
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From: San Diego California
Team Owner
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From: Western NY
FWIW, a number of years ago, while working on one of my "winter cars" (which wasn't a Corvette, of course) I found that the rubber "flex line" between the hard line on the frame, and the fuel pump, was in bad shape. So, I figured, since I was replacing the line anyway, why not stick a filter in there, along with a couple of new, short pieces of rubber line. As "doorgunner" said, might as well protect the fuel pump too....
Le Mans Master
Joined: Aug 2006
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From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
FWIW, a number of years ago, while working on one of my "winter cars" (which wasn't a Corvette, of course) I found that the rubber "flex line" between the hard line on the frame, and the fuel pump, was in bad shape. So, I figured, since I was replacing the line anyway, why not stick a filter in there, along with a couple of new, short pieces of rubber line. As "doorgunner" said, might as well protect the fuel pump too....
A regular rubber line can kink and block the fuel flow.