C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
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Old Jul 26, 2014 | 10:56 PM
  #1  
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msh7080
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Default Quadrojet

I have a 69 with a 427 and a Quadrojet carb, The carb. When I run down the road at 50 or 60 then stomp on the gas the secondarys seem to start to kick in then it loads up and sputters. It seems that either the secondary is not opening up or it is not receiving enough fuel or air? Manually I can open the secondary by moving the back throttle control and it seems fine, If I use the main throttle control on the linkage the secondary really never opens much. The vac seems to be working correctly and the mechanical choke seems to be ok. This is a new problem and the carb is only a couple of years old as I purchased it rebuilt on line and did not have this issue when I first installed it, however the car doesn't get driven much and I tend to baby it when I do drive it. Thanks msh7080
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Old Jul 27, 2014 | 09:01 AM
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Check the ignition system first-do a general tune-up. The secondary doesn't open? Do you mean the upper air valve or the lower mechanical butterfly?
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Old Jul 27, 2014 | 07:58 PM
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I run into this quite often. IF you have FLOOR MATS...this can be part of the problem.

Remove the air cleaner so you can WATCH your throttle linkage at the carb move.

IF you are by yourself:

Floor the accelerator pedal....and REALLY LOOK at where you throttle linkage STOPS.

Then remove the accelerator cable from the carb linkage and move the carbs throttle linkage and see if it goes FURTHER than what the accelerator pedal allowed.

If the carb need sot go further....then adjustments/modifications to the cable mounting area or the accelerator pedal will be required.

I do it more times that I can remember...and usually when people want to use floor mats...which can restrict the range of the accelerator pedal.

Due to not photos..I can only assume that the parts are installed correctly...and the point that the cable attaches to the carb throttle linkage is actually in the correct hole.

DUB
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Old Jul 27, 2014 | 08:01 PM
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The rear butterfly valve (secondary). the car runs fine no problems on regular driving, just when I press the accelerator hard to the floor; say like when I run down the highway and I want to open it up, stomp on the gas the car starts to launch then sputters
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