"dead spot" on take off

[billschroeder5842]

My '69 has a 383, mild cam, headers, intake, electronic ignition, new fuel pump and an Edelbrock carb. It starts everytime, idles great and mostly runs well.

I have this annoying "dead spot" when I accelerate. It happens about 1500 rpms. I have to take the gas pedal and "feather" it a couple of times to get past that point then it runs as it should. However when I punch it the motor revs up quickly and passes that rmp point without a hitch.

I'm not sure if it is gas related or ignition (I'm thinking gas), but it is a glitch in an otherwise pretty good car.

Anthing I should check?

[Mick70RR]

Is that the 750 Eddy Performer (1407), because if it is, it's a common problem and there doesn't seem to be a known cure. I gave up after about 12 months with that carb, I tried every suggested cure but nothing got rid of it completely. Try searching the problem on the internet, it's everywhere.

[billschroeder5842]

It is an Eddy but I'm not sure of the size. First one of these I've had.

[Hissing Cobra]

Find out which model it is and order the calibration kit. It's well worth the money. My uncle had this problem in his 350 cubic inch Chevy motor in his '46 Chevy Coupe. Once he ordered the kit, I was able to narrow it down to the springs on the Metering Rods. They "Pop" up depending upon vacuum in the motor and if the wrong ones are in there, they won't pop up quick enough, resulting in a temporary lean condition.

To get a mental picture of how these work, picture a hole with a rod going down through it. The rod has a spring that moves based on vacuum. When the the rod is in the down position, filling the hole, the car is leaned out, producing good idle and cruise ability. When you give it gas, the spring begins to move upards, opening the hole a little bit more, allowing more fuel to pass by and feeding the engine to produce more power. This is where the stumble usually appears because you're going from the idle/cruise circuit to the mid range (before wide open throttle). If you give it more gas, the secondaries will open and give you wide open power.

I've got two Edelbrock carbs on my Ford 302 and it runs flawlessley. Of course, I bought a calibration kit for each one of them and utilized them to make them perfect.

[FLG]

Holley double pumper.

[John_Kunkel]

The reason the Carter/Edelbrock carbs often suffer from an off-idle stumble is because their pump shot is weak just off idle...not much you can do about since it's inherent in the design. Running the idle mixture a little over-rich helps minimize the stumble.

[Chryco Psycho]

Eddys do run a very limited design for accerator pump shot , raising the float level helps a little , there is a bigger shooter available but you have to buy 3 to get the larger one , moving the pump rod closer to the carb will increase the volume slightly . these may help but I would recommend a Holley style carb , lately I have been using the Proform carbs for best results .

[68 RT]

It is leaning out, edelbrocks are lean from the factory. Buy the calibration kit and follow the instructions.

[billschroeder5842]

Thanks for the advice--I'll look into the kit.

[SRT-440]

My 440 in my Dart does the same thing...it has a Eddy 800. Prolly gonna replace it.

[dodgechar]

  used to have same problem  w/  my 750  holley,  but alot trail and  error tuning elimanated that,  for the most part the power valve, was the culptrit.  Dont know  edelbrocks.  get a holley boss.

[JPL]

Just fixed mine, a Holley 750 vac sec, it was a vac leak, 2 screws on the carb to manifold, and a couple on the fuel bowl needed tightening 90% better.

[morepower]

id really change the carburetor. you'd love the car so much more with a good holley double pumper, or proform, quickfuel, demon etc. that design is so much better for power

[Budnicks]

It could be ignition timing related also, advance curve or total advance, centrifugal advance springs or vacuum advance or combination of all...  After saying that... I would tend to agree about the Eddy carburetors are cheap & readily available, but the Holley style carburetors are more forgiving on tuning issues & will perform better in the long run, "Just my opinion"  I know there are guys who swear by them... I don't hate Carters or Eddy carburetors I've used a bunch of them, just the Holley styles of carburetors are easier to tune especially for the people that aren't experienced Eddy or Carter type carburetor tuner's.. Again I don't hate them they have their place it's just really not for performance in my opinion, unless your knowledgeable on how to extensively tune them properly for performance... Otherwise all of these post on the subject wouldn't keep coming up...