edelbrock carb issue

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A340 said:
Old Junk: Have same engine and carb issues as you. New carb, new engine with only 200 miles on it. Awful rich! Idle screws are set to best idle and vaccum. Everything else is set to specs that I can see.

Have you had any luck in getting your straightned out? If so, what did you do?

Thanks
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A340
The only thing I have done is change the springs to the lightest ones available (blue). I haven't really noticed a big difference. I'm not getting that tapping noise anymore, but it still seems to be running rich. I can't adjust the idle screws at all!:angryfir: I'm planning on putting an insulator between the manifold and carb because of issues with heat soak. When I pull the carb I plan on cleaning the thing to see if it makes a difference...and checking the floats. I begining to think strokerscamp is right...I may change my set-up if nothing improves.
 
Make sure your timing is set right, and also check to make sure the advance in the distributor is not locked out,(springs damaged, etc). If this is the case it could cause you to set the idle screw to far in, which will cause you to uncover your idle bleeds. Which could explain why adjusting your a/f idle screws have no effect. Just something to try, good luck. And do us all a favor. When you get it fixed, please let us know what it was for future reference. Thanks
 
540Valiant said:
Make sure your timing is set right, and also check to make sure the advance in the distributor is not locked out,(springs damaged, etc). If this is the case it could cause you to set the idle screw to far in, which will cause you to uncover your idle bleeds. Which could explain why adjusting your a/f idle screws have no effect. Just something to try, good luck. And do us all a favor. When you get it fixed, please let us know what it was for future reference. Thanks
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Good advice. An improperly working ignition can make it seem like a carb problem. The ignition is the first thing I always check.

As far as would the original thermoquad be worth rebuilding. How did it run last time you used it? They are great carbs when they run right but they have the problem of the bowls cracking and/or well plugs leaking. You can't get a new bowl anymore so if it's bad it's junk unless you get lucky and find someone with one for sale. BTW: They have a ton of parts so they aren't for the faint hearted rebuilder.
 
oldjunk said:
StrokerScamp,
I have the original carter thermoquad that came with the car. Would it be worth rebuilding?
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Heckfire it would. they are awesome carburetors. Nothing can compare on the street. They can get 20 MPG but be ready to dump 850 CFM when needed. What more could you ask? A chimp could fix the well plugs. All you need to do is remove them clean them up and use some gas resistant epoxy to reattach them. It's a common problem for them to leak but the fix is ultra easy.
 
I am curious, as I have had this problem before, and it wasn't the carb's fault at all. When you said it burns your eyes, that is pretty extreme.

Do you know how much fuel pressure you have at the inlet?

What fuel pump are you using? Carter high volume race pump? Regulator?

It sounds to me like you might be blowing the gas by the needle and seat.
 
HemiEd said:
I am curious, as I have had this problem before, and it wasn't the carb's fault at all. When you said it burns your eyes, that is pretty extreme.

Do you know how much fuel pressure you have at the inlet?

What fuel pump are you using? Carter high volume race pump? Regulator?

It sounds to me like you might be blowing the gas by the needle and seat.
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HemiEd,
I'm not sure how to check the fuel pressure...complete novice. I do have a fuel pressure/vacuum gauge that I picked up from the parts store. I just need some insight on how to properly check it. I think the fuel pump is stock...it says 'carter' on one side and part # 0-1994 'made in canada' on the other side. I'll post pic's of the fuel set up to give you a better idea. I'm not sure if I have a regulator. I have what looks like a fuel filter before the pump and a filter after the pump...is this normal? I didn't build this car, I bought it restored.

fuel1.jpg


fuel2.jpg


fuel3.jpg


fuel4.jpg


fuel5.jpg
 
Stupid question....but have you checked the clearance to all the choke linkage with the top of that air cleaner removed to make sure it's not holding the choke partially closed? Just a thought.
 
StrokerScamp said:
Stupid question....but have you checked the clearance to all the choke linkage with the top of that air cleaner removed to make sure it's not holding the choke partially closed? Just a thought.
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Yeah, just checked...no problems there. I do notice that the choke is partially open when cold, but I don't have problems with cold starting at all...fires right up. I know that edelbrock recommends it be closed with light spring tension on it, when cold. Correct? I haven't adjusted it because it's not giving me any problems. Thanks for your input.
 
oldjunk said:
Yeah, just checked...no problems there. I do notice that the choke is partially open when cold, but I don't have problems with cold starting at all...fires right up. I know that edelbrock recommends it be closed with light spring tension on it, when cold. Correct? I haven't adjusted it because it's not giving me any problems. Thanks for your input.
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It all depends on the climate. I've run a choke on very few of my cars. Bein in middle Georgia, there's just not much of a need. i don't know about light spring tension.....I'd adjust it so it is BARELY closed when cold. ...and I mean barely. That way, when the cold weather gets there, it'll probably be just right.
 
The filter before the pump has got to go.There is a sock (filter in the tank)that filters the fuel to the pump.Could be restricting fuel to the carb big time.

There is nothing wrong with an Edelbrock carb.For the street they can be tuned to run very well.They are also the easiest carbs to tune.If you cant tune your Ede,with the ease of them and parts available,you surely arent going to tune a thermoquad.

Any carb your working on,if you dont know how it works,and dont have it set-up right it will run crappy.

Get the manual for the carb,and learn how to set it up.
Usually these carbs run pretty dam well right out of the box.

Just wondering why you changed from the stock (yellow spring) ?

Did I mention get rid of the filter before the pump ?
 
silver step up spring those are the stiffest. start there

8" of vacuum is a problem with that carb. (at 8" i assume its a MP cam)

600 eddy will not work with more than [email protected] duration

check for a intake/carb gasket leak too
 
Johnny Dart said:
The filter before the pump has got to go.There is a sock (filter in the tank)that filters the fuel to the pump.Could be restricting fuel to the carb big time.

There is nothing wrong with an Edelbrock carb.For the street they can be tuned to run very well.They are also the easiest carbs to tune.If you cant tune your Ede,with the ease of them and parts available,you surely arent going to tune a thermoquad.

Any carb your working on,if you dont know how it works,and dont have it set-up right it will run crappy.

Get the manual for the carb,and learn how to set it up.
Usually these carbs run pretty dam well right out of the box.

Just wondering why you changed from the stock (yellow spring) ?

Did I mention get rid of the filter before the pump ?
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I agree with all this........but I still aint runnin a Crappelbrock. LMAO
 
I agree, that filter before the pump has got to go. Never seen that before. Eldelbrock carbs run great on mild engine builds. If your going for performance, edelbrock is not the answer.
 
It's pulling fuel because the idle circuit is WAY lean...that elec choak carb is just too lean out of the box for a 340...I fix this problem a couple of times a month all summer long...
I wouldn't put an Edelbrock carb in a wheelbarrow... the engines I build have camshafts with a min of 250@50 so that is out of any perf envelope that any of those carbs might cover.
 
Strokerscamp, It seems you REALLY like th eddie carbs. I got a 750 cfm I'm using as a paper weight right now. I'll sell it to you for a good price:) I'm talking from expirence also, I've ran both eddie and holley on the same engine with no changes and the holley pulled harder and ran smoother out of the box. 360/268 cam/10:1/3.23 gears/. Holley street avenger 670 cfm.
 
63dartman said:
Strokerscamp, It seems you REALLY like th eddie carbs. I got a 750 cfm I'm using as a paper weight right now. I'll sell it to you for a good price:) I'm talking from expirence also, I've ran both eddie and holley on the same engine with no changes and the holley pulled harder and ran smoother out of the box. 360/268 cam/10:1/3.23 gears/. Holley street avenger 670 cfm.
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Surely you're being sarcastic? I LOATHE the Edeljunk carburetors. I wouldn't put a Crappelbrock anywhere but in the garbage. The last Edelcrap I worked on ended up IN the scrap pile on the way to the recycler. THERMOQUAD all the way!!! Holleys are good for really high horsepower stuff. I've worked on a lot of cars with Crappeljunks on um too, so it's not for a lack of experience. They're JUNK, CRAP, GARBAGE, TRASH, REFUSE, SCRAP. Does that clear up how much I "REALLY" like them? LOL
 
There not really junk...they can get the job done,but for all the work that you put in to get them right the return is lacking...a set on kill Edelbrock 800 thunder carb is 20 ft lbs and 20 hp down from a std 750 Holley with duel idle and as much as 55 hp down from a set on kill 750 Nuytten or Bolaws or C&S type of carb..

years ago on moparts someone told me that he dynoed this new Thunder series carb and it was hp to hp the same as his own tried and true 800 cfm custom Chuck Nuytten or alike $1200 custom piece...I said bull ****..!! but he stood by his statement he said that the BSFC number weren't pretty but it made the same hp...Now this was a guy who wouldn't spend a buck to see a cyclone.So I was suspect...But that day I ordered a brand new Edelbrock 800 Thunder carb to do a dyno comparison with...At that time my 800 cfm dyno champ was a Bolaws...
So after setting the floats and getting the egt's and air fuel as close as I could using the Edelbrock carb the difference was 55 hp and a bit more tq....if your looking for hp...leave the Edelbrock in the box.
 
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