Carb secondaries not opening - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Notes · 07-16-2020, 12:58 PM

Edelbrock Performer 1406. Had to get a 1" riser so new fuel line from pump would clear the intake. Now the secondaries don't open at WOT. Vacuum lines are okay. It's also not as responsive as it used to be. Is there anything I can check without taking the carb off? Thanks

**HO455** · 07-16-2020, 01:15 PM

Make sure the spacer or gasket isn't hitting the secondary bore butterfly's or the linkages by manually opening the secondary butterfly's and inspecting carefully.

**Steeveedee** · 07-16-2020, 02:24 PM

Also check that you have WOT when the pedal is on the floor, not by moving the linkage under the hood. Something could have changed when you moved the carb up.

68Gold/white · 07-16-2020, 02:26 PM

The secondaries on that carb open via weighted arms that allow them to open in the same manner regardless of what size engine or what cam is in the engine.

You need to check what HO listed. You can fully open the throttle and try to push down on the secondary throttle blade with a screwdriver, to see if the blades are free.. If they do open, make sure they don't stick in the open position after release.

The responsiveness may have to do with the carb spacer. The spacer, I'm guessing is open in the middle, connecting both sides of the carb underneath the carb. This reduces the signal to each primary side of the carb, allowing less fuel/air mixture to be drawn into the intake, especially at lower RPM's. You need a spacer that seperates the sides of the carb (like the intake is...)

How long have you lived in Center Point???

07-16-2020, 12:58 PM	#1
Notes Registered User Join Date: Sep 2017 Location: Center Point, Iowa Posts: 82	Carb secondaries not opening Edelbrock Performer 1406. Had to get a 1" riser so new fuel line from pump would clear the intake. Now the secondaries don't open at WOT. Vacuum lines are okay. It's also not as responsive as it used to be. Is there anything I can check without taking the carb off? Thanks

07-16-2020, 01:15 PM	#2
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,276	Re: Carb secondaries not opening Make sure the spacer or gasket isn't hitting the secondary bore butterfly's or the linkages by manually opening the secondary butterfly's and inspecting carefully. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

07-16-2020, 02:24 PM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,591	Re: Carb secondaries not opening Also check that you have WOT when the pedal is on the floor, not by moving the linkage under the hood. Something could have changed when you moved the carb up. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

07-16-2020, 02:26 PM	#4
68Gold/white Registered User Join Date: Sep 2011 Location: Ark City, Kansas Posts: 3,385	Re: Carb secondaries not opening The secondaries on that carb open via weighted arms that allow them to open in the same manner regardless of what size engine or what cam is in the engine. You need to check what HO listed. You can fully open the throttle and try to push down on the secondary throttle blade with a screwdriver, to see if the blades are free.. If they do open, make sure they don't stick in the open position after release. The responsiveness may have to do with the carb spacer. The spacer, I'm guessing is open in the middle, connecting both sides of the carb underneath the carb. This reduces the signal to each primary side of the carb, allowing less fuel/air mixture to be drawn into the intake, especially at lower RPM's. You need a spacer that seperates the sides of the carb (like the intake is...) How long have you lived in Center Point???



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