high idle
Thread Starter
Racer
Joined: Feb 2020
Posts: 271
Likes: 76
From: long island NY
high idle
My 66 427 L72 has a high idle ,I have to kick it down almost every time I come to a stop .I kick it down and it idles fine .It idles at about 1500 then i kick it dow and it idles around 900-1000 .First what should it idle at and second how do i adjust it?
thanks
Mike
thanks
Mike
Safety Car
Joined: May 2007
Posts: 3,678
Likes: 646
From: Indiana
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First thing to check, take the air cleaner off and let it warm up and then see if the choke and butterfly are releasing all the way after you kick it down.
Pro
Joined: Jan 2013
Posts: 526
Likes: 118
From: San Diego
Agree with Gerald. Also, the curb idle is adjusted by a carb screw on LH side of the carb. If you google Holley curb idle, you will get lots of hits on adjusting it--very simple. My L72's idle speed is between 1,000 to 1,100. If I go lower than a 1,000 it tends to load up. My car is original motor with the exception of L88 cam, lightened/balanced flywheel and headers with 4" pipes (it was a former vintage racer). I run straight 110 Sunoco--the car is scary fast and super loud--love it.
Racer
Joined: Mar 2014
Posts: 309
Likes: 115
From: Central NJ
I find I must keep my stock L72 setup above 800 at curb idle. Always curious what others maintain and considered this too high but adjusting lower creates a stalling condition while idling especially at above normal operating temps, 200+ degrees. Is 1000 RPM normal for most?
Thread Starter
Racer
Joined: Feb 2020
Posts: 271
Likes: 76
From: long island NY
I feel stupid because I did not realize that when I was doing a bunch of work on the car I changed the throttle return spring .I got one from long island corvette, and it finally hit me that I started having this problem with idle right after that.I put the old spring on and it fixed the idle problem.the spring is much stronger than the one I bought .Maybe I try buying another and run a double spring
thanks MIKE
thanks MIKE
Safety Car
Joined: May 2007
Posts: 3,678
Likes: 646
From: Indiana
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 Corvette of the Year Finalist - Modified
2024 C1 of the Year Winner - Modified
2023 C1 of the Year Finalist - Modified
2023 C3 of the Year Finalist - Unmodified
2022 C1 of the Year Finalist - Modified
2020 C1 of the Year Finalist - Modified
2019 C1 of Year Finalist (performance mods)
2018 C1 of Year Finalist
Glad it was an easy fix. 
Racer
Joined: Mar 2014
Posts: 309
Likes: 115
From: Central NJ
I feel stupid because I did not realize that when I was doing a bunch of work on the car I changed the throttle return spring .I got one from long island corvette, and it finally hit me that I started having this problem with idle right after that.I put the old spring on and it fixed the idle problem.the spring is much stronger than the one I bought .Maybe I try buying another and run a double spring
thanks MIKE
thanks MIKE
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