Edelbrock 4bbl idle issue on 1973 302

[ustang73]

Bear with me on this. I will try to provide as much detail as possible. I'm a newbie and have an idle issue. 73 convertible, Engine is a 302 with a 4bbl Edelbrock with one of those triangle foam filters. The previous owner had a shop redo the top of engine and he added electronic ignition and the carb. Initially I adjusted the idle mixtures because it was shuttering when you were at a stop light, foot on brake in drive etc, shift to neutral and my idle screw adjustments helped.

By default the engine now idles at 1200 rpms which just seems high and loud. At times I can bang the accelerator and it drops to 800. I inserted a picture of the carb. I have a red arrow to the linkage in the pci. I can move that linkage with my finger to make it drop to 800 and idle fine. It seems that once I "unstick" it the idle drops and sounds great. The throttle linkage below this area (circled) seems to get in the way. Is this normal or should the linkage to my arrow swing freely? I'm not sure if this is normal, like I said if I fiddle with the bottom linkage the top swings free and idles great. Any help appreciated.

Dave

 

[Don C]

The arrow points to part of the choke linkage. Pull the air cleaner and make sure the choke is opening all of the way, it may be keeping the fast idle engaged.

It looks like something is jerry-rigged where the throttle linkage connects to the carburetor throttle lever.

 

[ustang73]

Thanks for the quick response Don, I'll check the air cleaner which by the way I have been struggling with, need to swap it out for an original kind. That triangle foam thing has some funky metal clip to keep it on the carb. Either way I will make sure the choke moves freely, test without the filter on etc.

If that doesn't help I will move on to the jerry rigged stuff and see if I can make it right.

One question... Am I on the right track here? The idle should be around 800 and the choke should move freely as it adjusts itself? Just want to make sure I shouldn't be messing the with idle screws again. Like I said it sounds great when that choke is free to move, idles at 800 and the neighbors don't complain.

Thanks,

Dave

The arrow points to part of the choke linkage. Pull the air cleaner and make sure the choke is opening all of the way, it may be keeping the fast idle engaged.

It looks like something is jerry-rigged where the throttle linkage connects to the carburetor throttle lever.

 

[Don C]

You are on the right track. One of my son's had one of those filters, once, they're a PITA.

 

[barnett468]

I don't see a throttle return spring.

1. Disconnect the vacuum advance hose and plug it until all your probs are fixed.

2. Set the idle low like around 600 rpms.

2. Check the timing.

3. Advance the the timing 4 degrees while it is running and see if the rpm increases much and if it still runs smooth.

4. Retard timing 4 degrees to previous setting.

5. Hold engine at 1/3rd throttle or 2200 rpm and advance timing and see if the rpm increases much and if it still runs smooth.

6. If it increases rpm and runs smooth under both conditions, leave it advanced 4 degrees.

.

 

[ustang73]

Folks, thanks for all the replies. I think it boils down to me getting better educated on these older cars. Your feedback helped me figure out that I need to wait for the engine to get up to temp, then the idle kicks down and she runs very nice. I recently changed out the filter to a standard model from that foam edlelbrock thing and get much better response from the engine when I need power. So thanks all for the replies, I guess it boils down to being patient with these older cars and getting educated by folks like you.

Thanks again !!

 

[piper62j]

The throttle return spring is part of the throttle cable on these models.. Not separate..

 

[jpaz]

There should be a second throttle return spring for safety.