So I know there is probably a thousand post on this issue, but I had trouble finding one to match my same basis.

I have a Edel. 750 Weber Carb on a 350 bored .40 over. Has a 268 Lunati Cam in it and headers. Now... I have leaned this carb out to the point that the car has died out. But it still runs rich. I had a friend suggest there was a vaccum leak somewhere and I wasn't getting enough air in to mix with the fuel causing raw fuel to be dumped out the back.

This is probably the best idea I've gotten since I've had the car.
Now the only problem is he got fired the day after telling me this.

So now I'm stuck with the possible cause, but no way to get to the solution.

What I'm asking is basically how do I check for a vacuum leak.

Ask me for any other details and I will to the best of my ability paint a picture for you.

Also car is a 1991 Camaro RS. started out its life as a 305. PO changed it to a carbed 357.

 

Stick a TINY wire down the air bleeds to clean them out. My air bleeds were clogged by rubber dust after I tried to make a rubber vent tube under my air cleaner... Rubber dust immediately clogged my air bleeds, engine started missfiring... Hydrolocked. Pulled the plugs and 5+ cylinders were FULL of fuel. It was crazy how fast it happened. I drove off the trailer and to tech... Clogged...


Tiny wire is found in a bread bag twisty tie...

Goodluck!

 

Check fuel pressure, too high pressure is a common problem for edelbrocks it seems.

 

I cleaned the whole carb, dismantled the whole thing and sat it in some clr and scrubbed it with a wire brush. But can't say for sure if I cleaned the air bleeds. Ill try that later today.

And as for fuel pressure. I'm running at 6psi atm. I've been slowly dialing it down. What's a good psi to be at?

 

4 to 6 psi for an Edelbrock.

 

Ive read 5-5.5 if you can set it with a regulator, mine was running 6-7psi and rich at idle

 

http://www.edelbrock.com/automotive_...404_manual.pdf

Page 8. No more than 6 psi at idle, no less than 2 psi at WOT.

 

For the record, what distributor are you running?

It's truly amazing how many carb problems are cured by fixing ignition issues.

 

Ok thanks for the replies,
I fed a tiny wire through the air bleeds, and the was little change if any.
I set the fuel pressure down to 4 (just to see how low is to low)
And I'm running a Delco-Remy Distributor.

About to give it a whirl and see if its running rich or not.

Also just wanted to double check, but there's only two air bleeds right?

 

So 4 PSI for fuel pressure was way to low. as was 4.5.
Sitting at 5 psi (where I had it before playing with it )
Still runs rich.

Any other suggestions?

Five7kid, What were you saying about Distributors possibly being the cause?

 

Inadequate timing advance at idle will require excessive throttle opening and low manifold vacuum at idle. Excessive throttle opening at idle and low vacuum will cause the main metering system to flow in enriched mod, causing a rich mixture.

What kind of Delco distributor? The stock '91 one?

 

By the way, putting a wire in the air bleeds will make it more rich.

 

See Page 3 of the instructions I linked.

 

I just used the wire to poke out any thing that may be clogging it, which there was nothing.

Also I'm not to entirely sure if it is the stock Distributor, But I'd say no more than likely.

And now after looking at the manual you linked, that I may just need to figure out a way to make the needle in the jet stay farther in, or for there to let more air in when accelerate. It really doesn't run to rich when I'm sitting at idle anymore just when I'm moving.

 

Your problems are similar to the same problems I had I did the fuel pressure check ,float check, then the re Jett. The remanfactured 750 I have part# 1411 was supposed to be jetted stock for a 402 cubed big block mine upon disassembly was jetted even larger than it was supposed to be which caused gas to mix with my oil which caused all sorts of issues and rich running problems. Too make a long story short make sure that's not a problem. The springs it should have come with stock are orange which are rich. the stronger the spring the higher the needle in cruise or power mode pending on your vacuum. So the blue spring which came with the tuning kit would flow the least amount of fuel yellow a little more, pink, orange, and silver i think was the highest(richest). Ater going through a few combos and checking the plugs my combo is .107 primaries and .110 secondaries 73x42 rods with yellow springs. And 4.5 psi hope this helps good luck