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I have a 68 chev Impala with a 307 2 barl. automatic. The problem is that when it is at Idle, at the stop light, it wants to Idle unevenly or surge. I have advanced the timing to 8 degrees BTDC the dwell is at 30, has new points and plugs and wires. I put carb. cleaner through it and the jets. Then readjusted the screws at a turn and a half out. Now, the problem is still there! Any help on this would be appreciated, Thanks, Joe.
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Willwood Engineering
Wilwood Engineering designs and manufactures high-performance disc brake systems.
Wilwood Engineering, Inc. - 4700 Calle Bolero - Camarillo, CA 93012 - (805) 388-1188
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The adjusting the idle mixture screws to 1 1/2 turns out is only a base setting. They need to be "tweeked" from there. Perhaps even up to a full turn one way or the other.
I would suspect the carbureor needs overhauling or there is a vacuum leak.
Gene Schneider
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The Mangy Old Mutt
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Thanks, Gene and Dog. Will look at these things in the morning. Thanks agin, Joe.
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Just a follow up here, on what I've done about this uneven Idle problem. I replaced all vacuum hose's, turned out the Idle mixture screws to 3 turns, and replaced the auto. choke pull off diaphram. Boy, it runs almost like a new car now!! It still diesels a bit when I shut it off though. Also, how do you know how far out and in to turn those adjusting screws?? Thanks for all the help!!
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You may have to lower the idle a little after adjusting the mixture screws.
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Thanks for the advice Don, Joe.
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Joe, Commonly the idle screws are set to max smooth idle speed. May need to reduce idle speed adjustment screw to get the 500-700 rpm idle speed. As Gene wrote there may be a turn or more deviation from recommended starting position.
How Sweet the roar of a Chevy four!
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The Mangy Old Mutt
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Thqnks guys, I'll have to get out the meter tomorrow.
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Well, I tweaked the carb, idle mixture screws, then set the Idle RPM to 600 in drive. The dieseling at shut down stopped, but the uneven Idle was still there a little! So then I re-tourqed the intake manifold bolts, boy were those loose. But it smoothed right out after that. A big THANKS to all here for the help, Joe.
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The Mangy Old Mutt
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