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C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
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Old Apr 8, 2013 | 04:19 PM
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Default Crazy Idle
Ah the joy of your first C3.

I took the air cleaner off bc I knew that the vacuum plugs were actually ends of rubber tube closed off with electrical tape. I put proper plugs on and now it idles crazy fast! I was doing 20mph in first w/o my foot on the gas. (In 4th I was doing 40mph w/o touching the gas pedal)

Upon getting it back home, checked the idle speed and it varies from 700 to 1250 on its own. Is this a case where the timing is off and I need to start there?

1970 L46. 40 yr old everything (not numbers matching).
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Old Apr 8, 2013 | 05:04 PM
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sounds like a vacuum leak. How did it idle before you plugged the hoses?
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Old Apr 8, 2013 | 06:29 PM
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Do you have your vacuum advance hooked to manifold vacuum? I have had this problem when I had the vacuum advance hooked to a ported vacuum source.
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Old Apr 8, 2013 | 06:31 PM
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Maybe your choke is stuck on high speed tang?
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Old Apr 8, 2013 | 07:02 PM
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Broken or missing mechanical advance spring can jack with the idle.
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Old Apr 9, 2013 | 09:33 AM
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It ran okay before I 'fixed' the bubba plugs with real ones. Not fast, not slow. I tried putting them back on, but same issue.

This weekend I'm going to go over to my buddy's house and we are going to check the timing (he has a gun).
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Old Apr 9, 2013 | 11:20 AM
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Guns and frustrating Corvette problems don't mix.
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Old Apr 9, 2013 | 11:47 AM
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Originally Posted by drwet
Guns and frustrating Corvette problems don't mix.
LOL...Timing Light (It is shaped like a gun so that's what we call it).
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Old Apr 9, 2013 | 11:50 AM
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Originally Posted by Navy01Coupe
It ran okay before I 'fixed' the bubba plugs with real ones. Not fast, not slow. I tried putting them back on, but same issue.

This weekend I'm going to go over to my buddy's house and we are going to check the timing (he has a gun).
No, fix your vacuum leak first. Two wrong don't make a right.
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