I give up

70NPORT

Old Man with a Hat
Joined
Oct 2, 2011
Messages
11,038
Reaction score
992
Location
South Jersey (USA)
A few weeks ago I bought a brand spanking new Edlebrock 650cfm AVS carb to go on my 383. Did the install, everything went well on start up: no erratic idle, no vacuum leaks, no fuel leak or smell, yada yada, and WOT down interstate 295 are beautiful (ever time). Fast forward to now: WOT is still nice however I cannot get the carburetor to idle worth a damn. After a few moments at a stop lights it will idle like a cylinder is dead. When I get back on the interstate and get the mph's up this condition clears up completely. I've checked a few things before throwing this out on the board:

vacuum leaks around the carburetor/intake manifold (negative)
too rich/too lean idle mixture (good)
spark plugs (all cylinders are firing)
Fuel, timing, blah, blah....this problem has gradually crept up to the point its a real chore to keep from shutting down from the poor idle at stops.

The ONLY thing I have not checked (and this was suggested by Edlebrock) are the float levels; apparently there should be exactly 7/16" space between the floats and the top of the carb (or bottom of the top). I guess that's next, but has anyone else run into this?? Was it bad float level or is there something else I'm missing??:icon_study:
 
A few weeks after installing a new carb, I found the mounting nuts had loosened causing a bad leak. Idled like %$^#
Had to Loctite and retorque them.

Also, I find it hard to believe it's a float problem. The symptoms are all wrong.

On a side note, I have never had an Eddie (or a Holley) run perfect right out of the box.
They are a universal fit meaning there's no car in the universe it will run right for.

never-give-up.jpg
 
Last edited:
A few weeks after installing a new carb, I found the mounting nuts had loosened causing a bad leak. Idled like %$^#
Had to Loctite and retorque them.

Also, I find it hard to believe it's a float problem. The symptoms are all wrong.

On a side note, I have never had an Eddie (or a Holley) run perfect right out of the box.
They are a universal fit meaning there's no car in the universe it will run right for.

never-give-up.jpg

yeah, I hear you loud and clear on the universal thing. Coincidentally, last weekend while putting in an ext trans cooler I took a moment to literally bath the base of the carb & nuts in carb cleaner iso of any latent leaks. Nada...and as if THAT wasn't enough, the last couple days she's starting to "diesel" a bit...about half a second or so after shutting down...which says to me now I've got unspent fuel trying to burn w/o a spark. :sad11:OY VEY!!!
 
Check your linkage, are your throttle plates closing to far and starving the motor for air at idle.
 
Check your linkage, are your throttle plates closing to far and starving the motor for air at idle.

Ill should probably check that out to elimate all possiblities...but this seems to be somewhat transient in nature...does not happen (choppy idle) immediately only after about 2 or 3 minutes of sitting at a light. Damn annoying.
 
Could be the float level...
I'd start there.
 
Do you have a stock cam? what is your Vac reading at idle? Does your carb have electric choke? Could be the electric choke is richening up the idle circuit (by limiting airflow and as the choke opens you are leaning out. Or if you have a non-stock cam it could be the metering rods and springs.Edelbrock usually sends a tuning book out with their carbs that covers most of the basics.Universal fit means the same to me as "plug and play" or "one size fits all" which literally translated means BS
 
Do you have a stock cam? what is your Vac reading at idle? Does your carb have electric choke? Could be the electric choke is richening up the idle circuit (by limiting airflow and as the choke opens you are leaning out. Or if you have a non-stock cam it could be the metering rods and springs.Edelbrock usually sends a tuning book out with their carbs that covers most of the basics.Universal fit means the same to me as "plug and play" or "one size fits all" which literally translated means BS

Negative on the cam, car is 2bbl 383 from the factory, it is rebuilt with 383/440 magnum spec cam thrown in for starters....and the carb is an electric choke model (edlebrock "thunder AVS" model). I have the Ebrock tuning book, but it might as well be in Swahili with a martian dialect....I NEVER read stuff like that -- if I do it just gets more confusing. I like to do things by my eyes, ears, nose, and sometimes even..taste (don't ask).

I was just talking to a local mopar engine builder here who builds for street/race and race/strip applications this morning and he says Edlebrock carbs are junk: you can either get them to idle nicely OR to WOT nicely, but you can never get them to do BOTH nicely at the same time. He happens to run a 72' Dodge Dart w/ stout 383 and 67 Coronet w/a forged crank 440. He switched both cars over to Holley carbs and then shopped the jetting work out to a carb specialist...has no problems whatsoever with them in that area (induction)....thinks I'm wasting time with the Ebrock setup....nice to hear, of course. If ONLY it would idle like it WOT's the world would be a nicer place.
 
Ill should probably check that out to elimate all possiblities...but this seems to be somewhat transient in nature...does not happen (choppy idle) immediately only after about 2 or 3 minutes of sitting at a light. Damn annoying.

If you neutral the car when it acts up will it level out.

Change your gas filter.
 
After years of fighting with Eddies, NEVER 100% sucessfully, I went back to Holleys. Them I know.
Now I'm learning Thermoquads inside and out...:Groaner:
 
After years of fighting with Eddies, NEVER 100% sucessfully, I went back to Holleys. Them I know.
Now I'm learning Thermoquads inside and out...:Groaner:


Prefer holleys also. I just think his problem is a simple matter of cable or linkage adjustment. Would explain why it's ok till it warms up. The tight throttle plates are cutting of air which is what you want on a cold engine, less air more fuel.
 
After years of fighting with Eddies, NEVER 100% sucessfully, I went back to Holleys. Them I know.
Now I'm learning Thermoquads inside and out...:Groaner:

I had a Holley 750 double pump carb on a worked 440 a few yrs ago and it was just as temperamental as the Ebrock seems to be.....the thing would not run worth a damn if it was humid or rainy outside, go figure. When the sun was out and the weather was clear it was dynamite. I 86'd it for a Carter AFB (before they were bought out by Ebrock)...worked better than the Holley in all weather.
 
Prefer holleys also. I just think his problem is a simple matter of cable or linkage adjustment. Would explain why it's ok till it warms up. The tight throttle plates are cutting of air which is what you want on a cold engine, less air more fuel.

Gonna look at the linkage this weekend, make sure that's not the problem.
 
I had a Holley 750 double pump carb on a worked 440 a few yrs ago and it was just as temperamental as the Ebrock seems to be.....the thing would not run worth a damn if it was humid or rainy outside, go figure. When the sun was out and the weather was clear it was dynamite. I 86'd it for a Carter AFB (before they were bought out by Ebrock)...worked better than the Holley in all weather.

That sounded like a moisture problem in your ignition system. I have always been a Holly fan as well but I am giving these old Carters a chance because they are correct on my cars, allthough I will be using a B engine six barrel set-up on my `68 Road Runner. I have a couple of books on carburators, one from Holley and the other is non brand specific but both are very informative and good reads.
 
That sounded like a moisture problem in your ignition system. I have always been a Holly fan as well but I am giving these old Carters a chance because they are correct on my cars, allthough I will be using a B engine six barrel set-up on my `68 Road Runner. I have a couple of books on carburators, one from Holley and the other is non brand specific but both are very informative and good reads.

I have a book on Carter carburetors (now Edlebrock) that goes over specs very every carter model made to date --and it's got pictures too!! (call me a dummy, but pictures are worth exactly 1.5275 billion words for me). That was a few years ago, I no longer have that car (but still have the 440 motor). I'm hearing alot of guys talk favorably about Holley carbs, but when I switched over to the AFB on that 440 the problems disappeared, immediately and for good. I guess since my first experience with a Holley was a bad one I'm hesitant to switch over now.......I wonder if you can mount a Quadrajet on a 383?





just joking.
 
I may have a very simple solution if it is a very simple problem, which from your original description it does sound right.

Take out your mixture screws and blast some compressed air through the ports, then reinstall your screws to your initial 2 turns out. You will know in short order if this worked and you can then do your final adjustment when it's warmed up.

It may sound dumb, but it has happened to me 6-7 times as I have quite a few vehicles that get run infrequently. It is just some little fliggin that gets lodged in your idle circuit, and everything seems fine just above idle.

If we are taking votes here I like the the AFB/AVS style carbs the best for most places, as they don't have any gaskets below your fuel level that can cause your carb to leak, as with the Thermoquad also. In my experience I have just had less trouble with the Carter based carbs.

One thing I suggest with the AFB/AVS is that you run an isolator to keep it cooler, so they start better when hot.

If you want all out performance for a street/strip car, the HP series Holley would be my choice.
 
Back
Top