ok here's the update....

changed primaries to #48 and secondaries to #56 (both are 8 increments smaller from original)

I am still experiencing HIGH IDLE....no more vacuum leaks and reduced jet sizes......Carb SNUFFS OUT quickly on the primary side!  

pictures to show how I eliminated vac.leak..take note of the last photos gasket:





 

Alright, vacuum leaks gone; changed primaries to 48 and secondaries to 56.

STILL Higher Idle. 

Tried turning down timing, but soon as I make changes, then adjust everything else according (mixture screws). It jumps back up. I'd say it's running 1-200rpm too high.

I can't figure out what the problem is!

You seam quite sure about the plates, but this is awfully strange so I'd re-check and make sure the orifices for the idle circuits are above the plates and there's no grooving or score marks or some other screwyness at that intersection.

If all checks out all I got left is raw fuel leaking somewhere instead of being drawn through the idle circuit alone.

Maybe a vacuum leak at the timed port for advance? I'm really hoping you get this sorted.

Sorry for the double post.

Last edited by Jon Richard (12/14/2018 4:08 PM)

M1Mustang69 wrote:

Jon, thank you Kindly for the responses....I appreciate your concern also.....I think youre right and I have concluded that as a last resort I will have to recheck the Throttle Plates.  I rebuilt the carb entirely; which means EVERYTHING was off.  I am very careful and particular but anything is possible!.....

I'm the same way, yet what I've found is as simple as these 4100's are, they can be a little fidgety and finicky about adjustments and changes. If the plates are all the way closed they will stick closed as they will try to wedge themselves in the bores- read, a tight tolerance.  

M1Mustang69 wrote:

to question the "Idle Orphancies being above the Throttle Plates"  if theyre not, how would that occur?  what would be a fix?

Do to their age and unknown history with multiple rebuilds with mix matched parts and shade tree tuning mods one never knows. It's doubtful it's the case with yours but I'm just suggesting to look out for any weirdness like that over the last guy that may have monkeyed with it. If a fix is needed I could help the best I could by measuring my carbs and feed you the size and placement info.

M1Mustang69 wrote:

I did mention the engine and trans, this is bolted to 100% stock and original 289 2bbl Mustang Engine!  C4 Auto...…..this EDC model is a pretty rare (im guessing on CFM) 1.06-1.08 model. the primaries are significantly smaller than the secondaries.

These do have smaller primary venturis but the bores and plates are the larger 1 9/16" rather than the 1 7/16" on the 1.08 4100's equipped on the 289. Since the EDC was engineered for an entirely different application this may be what you get without changing orifice sizes in the idle, transition, and main circuits. Those smaller venturis will deliver a stronger vacuum signal to the boosters, but the boosters and orifices were metered to work in conjunction with them to meet the demands of the heavier Edsel with the larger 361. The 289 will pump differently than the 361 so we don't really know how to expect it to run. This is why the 4100 swap and tuning is considered a black art, Ford never published info on the engineering nor meant for these to be ran in other applications or tuned beyong changing jet sizes, and there are significant differences between 4100 models.

Don't be discouraged, first make sure the plates seat properly. I've had rebuilds where an internal leak would siphon fuel and do to me what you're experiencing. Get it running and block off the boosters, if it changes RPM it's pulling fuel thru the main circuit instead of just the idle. And if that ain't it we'll think of something else to try 
 

Jon I repositioned the Scedondary Plates slightly, they were leaving a hairs worth of light through them (something you'd typically see from the secondary curb idle screw) but now they shut entirely when the screw is backed off!...….Im going to play with the Holley 600 Vac Sec. for a bit and see how that one goes, but this EDC has me baffled as to why the idle wont drop to a comfortable 500(ish) in gear...….

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