[71Cuda383]

I have a 71 Cuda with a 383, four barrel Edlebrock that runs rich at idle and 'stumbles'..... Where do I start? Any advice/suggestions /points in the right direction would be greatly appreciated. Thanks in advance!

 

[dana44]

Welcome to the forum. The Edelbrock carbs are pretty easy, and even though I am more of a Holley tuning guy, there are a couple things to start with. There are several tuning guides on the internet, but to get you started, Set the two idle screws on the front at two full turns out (be gentle bottoming them out to adjust, don't want to damage the needle ends). With the engine running at idle, turn the two idle screws on the front of the carb in quarter turn each side until she starts to stumble, then turn them out half a turn each side, they will be set. You should be at between 1.25 and 1.5 turns out. The accelerator pump is controlled by a rod that goes from the throttle to an arm on the front top edge of the carb and has three holes in it, make sure it is in the center hole to start. The secondaries are probably the stall, there is a large screw on the side of the air horn that controls the secondaries opening with a spring that controls the amount they open based on the vacuum. The screw controls the tension, most likely too loose, allowing them to open too fast and stumble. Start tight and over the next few driving cycles adjust looser until she starts to stumble, then go backwards. There is a needle adjustment but I recommend doing a quick search for Edelbrock tuning instructions, this will at least get the stumble and richness fixed, I have used the videos and examples myself, not real difficult to follow.

Sounds like a nice car, tell us how it goes and more info please.

 

[71Cuda383]

Thank you very much for the tips. I have set Sunday aside to try and adjust it. I put a K&N filter in it and it seems smoother, but still needs some tweaking. I will let you know how it goes.

 

[71Cuda383]

Turned the idle screws and took her out for a run. Stumbled a little and actually backfired once so stopped and turned them a little more. Hit some paved country roads and let her run and was better but still a little hesitant at times. Pulled over and turned them another quarter turn and was much better. Had to put it away for the week but may try turning them again when we take her out and go from there. We`ll see what happens. Thanks again for the tips. I was hesitant about messing with it but I see now that it`s not as complicated as it seems, and that it can always be put back.

 

[Bob Lincoln]

Idle screws only affect....idle.

So adjusting them will do absolutely nothing above idle. A full rebuild is probably in order.