Carb whistling Dixie..
Thread Starter
Instructor
Joined: Nov 2022
Posts: 158
Likes: 82
From: North Coast
Carb whistling Dixie..
Took my car for a spirited drive recently, dug a little deeper than I usually do.
upon returning home I noticed a high pitched whistle emanating from the engine bay.
initially thought vacuum hose or related component leaking but after some poking and prodding I narrowed it down
to the carb. Spraying carb cleaner around the base produced no change.
when I tinker with the front butterfly it stops, when I let it back to normal it starts again.
Never done this before so I’m wondering if something came loose when I was hammering on it.
327/350 w Edelbrock Quadrajet carb.
thoughts?
upon returning home I noticed a high pitched whistle emanating from the engine bay.
initially thought vacuum hose or related component leaking but after some poking and prodding I narrowed it down
to the carb. Spraying carb cleaner around the base produced no change.
when I tinker with the front butterfly it stops, when I let it back to normal it starts again.
Never done this before so I’m wondering if something came loose when I was hammering on it.
327/350 w Edelbrock Quadrajet carb.
thoughts?
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Throttle Shaft Bushings.
Think about your daily driver. We never or seldom raise the hood and start revving the throttle. Even if you could find the throttle.
Now lets look at your Vette. Likely the hood is up every week. A little tuning here. A little tuning there. Rev it some more. Play with the carb. More revs.
Plus you have a throttle cable pulling on the shaft bushings. Return springs pulling in another direction. It's a wonder the shaft bushing last as long as they do.
You have some play in the shaft. You have a couple of choices here. There is a throttle bushing repair kit at Summit. Comes with either four or eight bushings, drill bit, new shafts, etc. If you go this route, you really need a drill press and a rock steady hand. If you don't drill it perfect, you will be no farther ahead of the game.
Option 2. Buy a new base plate. Depending on what carb it's for, you may get an extra vacuum port included. That is always a bonus on these vacuum mobiles.
Update: On most carbs it's the primary shaft, drivers side bushing that gets the most abuse for obvious reasons. You said the whistle changes when you wiggle the shaft.
You will likely need to change at least the primary shaft bushings.
Think about your daily driver. We never or seldom raise the hood and start revving the throttle. Even if you could find the throttle.
Now lets look at your Vette. Likely the hood is up every week. A little tuning here. A little tuning there. Rev it some more. Play with the carb. More revs.
Plus you have a throttle cable pulling on the shaft bushings. Return springs pulling in another direction. It's a wonder the shaft bushing last as long as they do.
You have some play in the shaft. You have a couple of choices here. There is a throttle bushing repair kit at Summit. Comes with either four or eight bushings, drill bit, new shafts, etc. If you go this route, you really need a drill press and a rock steady hand. If you don't drill it perfect, you will be no farther ahead of the game.
Option 2. Buy a new base plate. Depending on what carb it's for, you may get an extra vacuum port included. That is always a bonus on these vacuum mobiles.
Update: On most carbs it's the primary shaft, drivers side bushing that gets the most abuse for obvious reasons. You said the whistle changes when you wiggle the shaft.
You will likely need to change at least the primary shaft bushings.
Last edited by HeadsU.P.; May 28, 2023 at 10:25 AM.
Le Mans Master
Joined: Aug 2006
Posts: 7,423
Likes: 1,558
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Thats what my "abused" Holley did with worn primary throttle shaft bushings.
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