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Discussion Starter · #1 ·
Just got a customers car running and he gave us a new Edelbrock carb to put on it. This is a rebuilt 289 with Edelbrock RPM heads, Edelbrock 600 carb, Edelbrock Performer manifold, headers, mild unknown cam. The engine sounds great when it was fired up for the first time. We broke the cam in properly and made timing and idle adjustments with it. I took it out in the parking lot to see how it would run and it has a big hesitation to it. I thought the accelerator pump did not work by the wat the car falls on its face. I pulled it back in and looked at the accelerator pump and it squirts a good amount of fuel. I have never messed with an Edelbrock carb, I am a holley guy. One thing I failed to mention is right now this car has no exhaust. It is open headers. Should I wait until the exhaust is put on til I try to get this hesitation worked out? Should I try the next size metering rod? Is the Edelbrock just a piece of $hit? The timing is properly set and the car pulls 15" of vacuum at idle. Any tips?
 

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The accelerator pump has 3 holes for the rod. It's set to the middle hole from the factory, so try going to one on either side of it.

I has this same problem with mine. After adjusting the pump, no more hesitation.
 

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Actually, Edelbrocks have step up springs that push up the metering rods...the ones that come with the carb are really weak...meant for a cam with about 6 inches of vacuum or something. You need to buy a stiffer spring for it...don't go too stiff, or you'll totally wreck the mileage. I doubt messing with the accelerator pump will help in this case (personal experience).
 

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Discussion Starter · #7 ·
I saw the 3 holes yesterday. When I was looking at the carb tuning instructions I seem to remenber them wanting to addust the metering rods first and then the pump last. I could be wrong. I cant believe how bad the hesitation is. All the Holleys I have installed through out the years, none of them hestitated like this. Wont the fact the the car currently has open headers run different then with the car having an exhaust system on it?
 

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Discussion Starter · #8 ·
I did see the springs and it was mentioned in the instructions. How can I tell what springs I need? I dont like this Edelbrock! I wish this customer bought a Holley! Chances are I wouldnt be posting a problem but more like" this 289 hauls a$$!
 

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I solved a issue with an edelbrock I had with a Holley. :Lol:
 

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Try the pump first. Trying that will cost you nothing. Trying tuning the springs with new ones will cost you bewtween $45 and $60 (buying their tuning kit), depending on which specific carb you have.

I will also restate that changing the accelerator pump fixed my hesitation yestersay. Tho I did already change the jets and other stuff in mine around.
 

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What Big Bad Beater said, you need Step-up Spring assortment #1464 or Calibration Kit for your particular Carb. I bought the Calibration Kit from Jeg's #350-1487 for my #1406 carb. The strongest spring fixed mine. The kit includes along with the 5 pair of step-up springs an assortment of metering rods and jets.
If you don't have a copy of the owners handbook you can down load it at www.edelbrock.com . I'm goin' to figure this thing out then get a Holley! Jim
 

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Is it the new Thunder version?? If so perhaps the rear air valve is misadjusted. It can be easily be reset. As Far as carter/edelbrock carbs have used many over the years. The farthest out of adjustment I have ever seen with them was my last one, a 650 thunder, good luck.
 

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Discussion Starter · #13 ·
Im not sure which version I have. I have to look at the box. I will try the pump adjustment first. I dont remember seeing anything in the insructions about adjusting the secondary air spring. how is that done? I really need to have the exhaust on this car before I start doing to much to the carb. The State police are about 1/2 mile down from me and I dont think they will like me cruising the streets with open headers tuning this carb in.

<font size=-1>[ This Message was edited by: Blue Fastback on 4/30/06 8:40pm ]</font>
 

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The Edelbrock carb is a reliable and effective unit but set-up is critical, take your time to set-up and adjust correctly.

Hessitation can be caused by rich & lean fuel conditions during a transition stage in the carb

First check your fuel pump pressure. Edelbrock carbs are very sensitive to any fuel pressure above 4.5 psi. Use a low pressure fuel regulator if the fuel pressure is too high.

Second follow the Edelbrock set-up process found in the manual or on my website (mentioned above & linked below) just changing the pump stroke may help, but it may also create other drivabilty problems.

http://www.telusplanet.net/public/gilesij/Volvord/edelbrock_1.htm
 

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Discussion Starter · #15 ·
well I incerased the accelerator pump stroke and the hesitation is gone. The other problem I have know is this car has a hard time roasting the tires off the line. The engine should put out plenty of horses to do that. I think I need to do more fine tuning but am happy the big hesitation is gone. I think a heavier metering rod spring would help me out but thats down the road. Thanks for the help.
 
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