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Old 11-12-2003, 08:03 PM
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Q jet won't idle!

ok this is strange.. i did a rebuild on this carb.. and put it on for winter.. i havent had this carb on since i did my cam swap... so was curios to how it was gona run.. well its weird cuz at idle it wants to die after sitting still for a bit.....out of gear.. and also i was thinkin i should try adjusting the air screws.. but wut kinda tool do u use for that?? then i was thinkin maybe its the new float?? getting to much fuel at idle.. flooding it.. so maybe i gota bend the float a little bit??? would do u guys think it could be? my holley idle"d awsome...

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Old 11-12-2003, 08:18 PM
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There are specific settings for your float to be set at. The setting came with your rebuild instructions, and how to measure it.
Some Quads have idle screws and some of them are sealed. If there are screws there adjust them for the highest vacuum.
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Old 11-12-2003, 08:27 PM
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Well, you make it sound like you have a new float for the carb, and unless it's the exact same type, shape and size, you'll have to wing it on float levels. If it is different, I guess I don't know why you'd have changed it. Either way you want to have your float adjusted so that you're not running out of fuel before you intend to remove your foot from the floor- if it dies midway down the track, you know it's too low. A good starting point is around 9/16" down though, if all else fails.
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Old 11-12-2003, 11:12 PM
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Grab some WD-40 and spray around the carb. If you notice a change in RPMs then you've got a vacuum leak. I remember when I had my Q-Jet rebuilt. Went to get a new set of gaskets and was given the wrong ones. The thing was hissin like a rattle snake. If no vacuum leaks then check the idle air/fuel mixture screw's.. And this may sound kinda dumb.. But I figure it never hurts to ask... Have you adjusted the Idle set screw?
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Old 11-13-2003, 09:06 AM
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You probably have the oblonghead screws, most partstores have a tool for them, Look down in the carb while idling, you shouldn't see any fuel in there, if you do, your dumping gas, poss float setting, with the top removed, the top of the float should be close to 1/4" down and parallel with the top of the body, if you didn't see any fuel ,adjust the mix screws, in till idle drops, out till idles rough, halfway back in!HTH
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Old 11-13-2003, 06:21 PM
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thanx for the replys.. i'll give it a shoot.. bye the way my idel screw is set at 1000 rpm right now.. just to keep it running.. especialy when cold! i'll search for the tool to adjust the air screws.. let ya guys no how it goes.
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Old 11-13-2003, 06:44 PM
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idle problem

I had a 1903 Q-jet and had similar problems. To rectify I did the following:

Modified mixture at the two screws on the bottom plate on the front of the carb. Use a vacuum gauge when doing this to ensure proper mixture. Adjust to best vacuum and idle, then back off idle set scre, do again, back off screw etc... until you get best idle and vacuum. To set set screws turn all the way closed then start with 1.5-2 turns open.

made sure all those stupid extra vacuum lines were capped good.

Adjusted choke settings. That was a big problem. Once I got it adjusted I was getting better idle. When you ahve your engine running at it's current idle take your finger and slowly open and close the primaries butterfly and listen for the idle to increase or decrease. If it increases it is your choke adjustment.

If you can get the idle to increase with choke adjustment then mod your idle screw adjustment as well.

Don't forget timing. I prefer to time with a vacuum gauge, timing lite and a tach all at the same time. It is kind of a paint to try to view all of them but it is your best timing.

Don't time with the vacuum advance attached to the dist. Make sure vacuum advance is capped on the carb as well.

Rick
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