I have a Ray Barton 528 hemi in my cuda and the car runs so rich to the point that where my eyes burn real bad if I stand next to the car for more than a minute. The motor has less than an hour of run time since I bought it. It has two edelbrock performer 600 cfm carburetors and they were setup when the car was dyno tuned. Brand new msd distributor with 6al box and edelbrock performer mechanical fuel pump. Fuel pressure is 7-7.5 psi. The car ran fine last fall and I went to start it up to get it ready for the summer and it is running like absolute garbage now. My first thought was the gas went bad over the winter so I drained the whole system and filled it up with fresh gas with no luck. I have to give it gas to keep it running and it acts like it is loading up when I rev it. There aren't any vacuum leaks anywhere that I can find. Is it possible that the fuel pressure is too high and pushing past the needle and seat and just dumping into the motor? This is already the 3rd fuel pump that I had to put on this motor as the first two were bad right out of the box and were putting out 9 psi and flooding the motor. Any help would be greatly appreciated.

What fuel pump? Should only be about 6 psi.

Mechanical Edelbrock performer. The description for the pump says it makes 6 psi max and the first two made 9 and the last time I ran the car it was at 6 but now it is a little over 7.

http://www.edelbrock.com/automotive/mc/carburetors/pdf/carb_owners_manual.pdf

Page 5 gives fuel pressure specs, says to set it at 5.5 psi at idle.

Being a dual quad setup you probably will need more volume but not more pressure than a single setup.

I've also seen the brass float get pinhole leaks over time and start sinking. Make sure your needle and seats are not leaking by.

If your using a fluid filled gauge near engine heat it might not be accurate.

I bought an Air Fuel Ratio gauge for my 70 Challenger. Best money I ever spent on a gauge. I now can tell the AFR at every level of load etc.
It sure beats pulling the spark plugs out and checking.

First i would get a simple spark tester that is adjustable and can read the kv output of the the spark i have one in my tool box .
MSD should jump a blue 1 inch long spark no problem . 45kv no less.
second you could take a flash light and look into the throtle at the main boosters to see if it is dumping fuel there should be no droplets coming from the boosters under say 2800-3000 rpm .
If you see the boosters dribble fuel at idle then floats set to high or fuel pressure to high.
third 7 psi is not that high but i would follow the Edelbrock recommendations. Do you have a fuel pressure Regulator?
IF no i would get one! and set the pressure where you want it.
Also you can use a timeing light to see fuel spray coming from the booster in the carb throat while increasing the RPMs.
Also could the timing have changed ?
that motor prob likes 18 to 20 deg initial at say 1000 rpm and 34 total all in at 2000-2200 rpm.
I would start with this .

Pretty much what's been said above:

#1. Fuel pressure (if accurate) is too high, 6-6.5 max.

#2. Float level too off, Carters/Edelbrocks need to be set right, also look for a sunk float, even brand new ones sometimes have tiny pinholes, also bad gas can easily clog a needle & seat open overfilling the bowl.

#3. Vacuum leak somewhere, Hemi's like to suck intake gaskets, hard to find but very common.

The gauge is not liquid filled, however I don't have another gauge to compare it to for accuracy. I didn't install a fuel pressure regulator because when I called edelbrock about the problem with my first two pumps, I was told that I didn't need a regulator with that pump and that there was no way to adjust the pressure of the pump. I didn't install a regulator after that either because I figured it would only be masking the problem of the pumps being that they are only supposed to make 6 psi max and not 9. I will try to get a helper tomorrow to keep it running so that I can look down the carburetor and see whats going on.

I don't have a tester to measure the output of the spark, but when I pulled a plug and cranked the motor over I had very strong spark.

I'm betting on a float or needle & seat issue.

Are the rods being pulled down at idle? They should be.

open the star screw (two of them) on top of each carb, and rotate them a bit to see the enrichment rods.

Put new spark plugs in it, then see how it runs.

^^^^^^^^

This too.

Did you have the same gas in it all fall/winter with no stabil? I was told it had shelf life of 30 days. You may have goo in your bowls/needle/seat. Any gas coming out of the primary vents or do you see fuel wetness on top/around the carbs?

Since it ran fine before parked and now runs rich, the bad gas scenario is most likely the culprit. Time to open it up and see what's going on inside, having a buddy "look down the carb" isn't going to get you anywhere.

The metering rods are down during idle as far as I can tell and I took a look down the carburetor while it was running and gas was pouring out of the boosters so definitely either the needle and seat or fuel pressure. . Im going to pick up a regulator tomorrow and try that next.

Did you loosen the screw and slide the cover off to the side so you could see the rods with the motor idling? Rev it just a bit and watch them jump up?

I have been using 600 like yours since like 1985. Been on every 340 I ever had at one point or another. I have tuned it quite a lot since I trailer it on vacations all over the country including driving it to the top of Pikes Pike twice. They got to be lean to make up that mountain.

Anyway just recently put a temporary fuel gauge on my mechanical fuel pump equipped 340 and had 6-8 PSI depending on RPM and throttle position.

My car also has the hemi vapor separator mounted on the fuel pump connected to a factory 1/4" steel return line. It has a 3/8" suction line for the fuel pump. It was the first time I checked fuel pressure under load with the hemi VS/return line and I had plenty of pressure even under WOT. Been driving with this fuel setup for 10 years and 25K miles since 2007 on my most recent 340 with my trusty 1405 600 carb..

IMO 7-7.5 psi fuel pressure is not your problem.


What do the spark plugs look like? Get used to pulling them out, you need to keep track of them.

The Edelbrock carbs will get "eaten up" by the ethanol content in pump gas if they are allowed to sit for a long period of time. If you pull the tops off of the carbs you'll most likely find some white slime in the bowls. That slime gets into the fuel passages and blocks things up. My guess is that you're actually running lean not rich due to a blocked passage. People think the stinky idle is rich but typically it is dead lean and misfiring.

Ok, I will pull the top of the carbs tonight before I buy the regulator. Definitely running rich and not lean though with the amount of gas that was dumping into the motor.

If you have gas coming out of the boosters then you probably have a problem with the needle and seat.

It isn't uncommon for these carbs to develop issues if you let them sit for very long with ethanol pump gas in them. I had an old truck that I didn't drive very much with an Edelbrock carb on it and I constantly had to pull the top off the carb and clean it out. The pump gas swill just eats at those carbs if it sits in there for very long.

I pulled the tops of both carbs off and it was clean inside. No white slime or residue from the ethanol. Pulled out the needle and seats and they were clean too. I cleaned everything up with carb cleaner, rechecked the float adjustment and put everything back together and it still wont idle by itself and it is still leaking gas out of the boosters. If I give it just a little gas it will stay running, but it still has very strong fumes from the exhaust that will burn your eyes even after a few seconds of it running. I'm ordering the fuel pressure regulator tonight and I'm really hoping that this will be the end to the problem. I appreciate all the help so far.

Did you verify the floats were not leaky? If so, how?

They were floating on the gas that was in the bowls and when I pulled them out they were not full of gas.

Did you shake them and listen for slosh? Doesn't take much to keep the needles from seating. Had it happen twice to me over the years. First time I resoldered the seam, couple years later I just replaced them.

I didn't shake them, but I did take them off to clean the needle and seats and I couldn't hear anything moving around and they were very light so I'm almost positive that they are still good.

I got the fuel pressure regulator installed and it does seem to run a little better and nowhere near as rich, however the problem is still there and I cant get the car to idle. I have the regulator set to 6 psi. I pulled out all the idle mixture screws and sprayed some carb cleaner in there and into the air bleeds as well. Does this sound like an idle circuit problem? I still cant get the car to idle by itself to see if everything else is okay.

The only way that I can get the car to idle is if I turn the idle up to around 1500-2000 rpm; I'm not sure as My car doesn't have a tach.
The vacuum was at 5 in/hg and when I looked at the metering rods, they appeared to be bouncing up and down a little bit. Im not sure if the vacuum is that low or the metering rods are bouncing slightly because of the idle being so high.

I run a pair of 750's atop a blower. As others have suggested, Edelbrocks are sensitive to pressure and float height.

I'd get your pressure down to 5-5.5 psi. (Up to 7 with a Holley)

If it's still flooding internally and the float isn't leaking, try lowering the offending float(s) slightly.

The stock step-up springs (orange) are rated at 5 in/hg. So if your engine is hovering at 5" vacuum at idle, the rods could be lifting (richening). Get your vacuum up or switch to stiffer springs. I'm leaning towards pressure/float height.

I took the whole carburetor apart again, cleaned everything again, lowered the floats a little more, and dropped the fuel pressure down to 5 psi and the car still will not idle. It is still running rich too. It only wants to idle at roughly 1500 rpm. I can sill see gas coming out of the boosters, but I believe the only reason now is because of how high the idle is. I am pretty much at a loss of what to do at this point.

You raised the float? That would make the problem worse. If you lower the float it will shut the fuel off at lower level in the bowl.

My bad, just a typing mistake. I lowered the float.

Does anybody here have a hemi, preferably 528, and know an average vacuum reading at idle?

Is there a set adjustment as to how far the primary throttle blades should be open at idle?