Edlebrock carb problems

[47convert]

I'm having trouble with my 600 CFM Edlebrock carb and I know a lot of you guys love them so here goes: This is the second Edlebrock I've had on this engine - the first being a manual choke and this one with an electric choke. The 350 Chevy is basically stock with an air gap dual plane intake and dual exhaust, followed up wit a Muncie 4 speed. The car continually runs way too rich, smoking out of both exhaust (black smoke) every time I touch the gas or shift gears. My gas mileage is horrible and it's sometimes hard to start because of flooding. The first carb acted the same way and they were both brand new with no modifications. I use a stock GM manual fuel pump - could it be putting out too much pressure? I lnow - get a gauge and check it - I'll do that tomorrow. What else could it be?

[rumrumm]

Edelbrock carbs like about 5 lbs. of pressure. Since both carbs have done this, I would guess fuel pressure to be the main culprit. You may have to lean it out with jets and/or metering rods since you have a basically stock 350.

[reborn55]

Edelbrock carbs have a tendency to be shipped with incorrect float settings.  may want to check that.  May have to do some recalibrating--a jet and rod combination---Friend uses #1426 jets--.095 and #1456 rods--.073x.047. Good results.   May also try switching primary and secondary jets.  making the primaries smaller.  If you have a hard start hot a 1 inch phenolic spacer will help.

[Mikej]

You also need to make sure the throttle plates are closed. If to much of the transition slots are uncovered ,it will run to rich. This will be gassy, burn your eyes, at idle. If you can adjust your idle screws in and out with no difference than the plates are open to far.

[slocrow]

I'm having trouble with my 600 CFM Edlebrock carb

47convert; I've got similar problems with my 750 manual on a 402BB/700R4. Because of the way it ran I also perceived it to be running rich. I've gone one step down on both the primary jets and rods with some mileage improvement and believe it's still running rich. If it was rich the step downs didn't much help my bog problem. Oh, it helped somewhat but not enough. I then believed it was a heat (percolation) problem so I installed a 1/2" phenolic spacer which didn't seem to do anything. Off the line the car still runs strong when cold but when hot it can pop and bog like it's loading up, with anything more then half throttle. Mid-range is unaffected.
I stopped by the Edelbrock trailer again last weekend at GG Indy and spoke to a rep about my apparent heat/perk problem. He agreed and suggested a new product they have which is used instead of a phenolic spacer. It's a new product they offer, a two hole heat gasket with crush proof mounting holes. It's suppose to keep the heat away from the carb. His opinion was that the phenolic was just a spacer and not a heat shield.
I'm installing it today. We'll see on the trip to KY this weekend.
I'll probably jet down again today as I still think I'm rich and need to check the jets & seat as I smell gas after I shut down.
I mention this because yesterday when I inquired they (Edel) mentioned that stock pumps can put out from 3 to 9 pounds pressure. Though that line is one their techs have been using for years, to direct away from their product I believe.
Good luck with your carb problem and let us know.........Frank

[Dave]

I'm having trouble with my 600 CFM Edlebrock carb

47convert; I've got similar problems with my 750 manual on a 402BB/700R4. Because of the way it ran I also perceived it to be running rich. I've gone one step down on both the primary jets and rods with some mileage improvement and believe it's still running rich. If it was rich the step downs didn't much help my bog problem. Oh, it helped somewhat but not enough. I then believed it was a heat (percolation) problem so I installed a 1/2" phenolic spacer which didn't seem to do anything. Off the line the car still runs strong when cold but when hot it can pop and bog like it's loading up, with anything more then half throttle. Mid-range is unaffected.
I stopped by the Edelbrock trailer again last weekend at GG Indy and spoke to a rep about my apparent heat/perk problem. He agreed and suggested a new product they have which is used instead of a phenolic spacer. It's a new product they offer, a two hole heat gasket with crush proof mounting holes. It's suppose to keep the heat away from the carb. His opinion was that the phenolic was just a spacer and not a heat shield.
I'm installing it today. We'll see on the trip to KY this weekend.
I'll probably jet down again today as I still think I'm rich and need to check the jets & seat as I smell gas after I shut down.
I mention this because yesterday when I inquired they (Edel) mentioned that stock pumps can put out from 3 to 9 pounds pressure. Though that line is one their techs have been using for years, to direct away from their product I believe.
Good luck with your carb problem and let us know.........Frank

Geeze Frank thanks for sharing the new heat spacer thingy now after im home? My Edelbrock has sucked from day one also. I get great mileage but the idle sucks and it vapor locks at high speed not at an idle. And yes if hotrodsrj chimes in i set the float and did all I can do. Ive run 3 of these now and 2 were good but this one is junk......... I hat to say it but if I had or maybe wanted to spend the bucks right now id buy a new holley and put this pos on Egay...............
Dave

[slocrow]

Geeze Frank thanks for sharing the new heat spacer thingy now after im home?

What are you talking about? I shared that info with you extensively. You said thanks and that you had to get back to your gin. Don't you remember?
..........Wait a minute, at least I thought it was you. There wasn't anybody there that looked like you a little, was there? If so then that's who I shared that info with while you were driving around by the airport. Yeah that's it, I told your look alike...........(smile).

[32coupe]

Oh my my, when are you guys going to learn the benefits of propane?
I don't have any of these problems on any of the cars that I have fitted with an off the shelf, or even a swap meet, propane carby.

I have never had to jet one, the ones that I use dont even have jets. I just set the idle mixtures and fire it up and drive.


Good luck with that gas stuff you guys love so much.

ps: no vapour locks either.

[Pope Downunder]

I'm having trouble with my 600 CFM Edlebrock carb

Good luck with your carb problem and let us know.........Frank

I support what Frank says here.  At the Nationals (US) I fronted the rep and he gave me one of those reinforced gaskets.  Mine would boil dry when shut down hot, and make starting difficult.  This cured that problem.

My 500CFM manual choke carb was received with metering rods and jets for a blower motor (WAY TOO RICH) and with bent metering rods.  This is a real PITA when firing a fresh engine.  When we got the calibration in the ballpark it bogged off the line.  After some fiddling with metering rods and springs this was eliminated.  

For example, if you are not generating a decent vacuum, and the springs are too stong it will run rich. If you weaken the springs, it may run lean under power and backfire.

I am now returning acceptable fuel mileage and driveability is good.

[reborn55]

Kinda funny how things change.  When I was having problems with heat soak, the edelbrock rep told me to use the black one inch spacer--even gave me the part number.  Have been using it for around 4 years now with good results.  Things change as time goes by.

[BFS57]

Hello All;
I'm kind of a new guy but I, like some of you are experiencing the very same problems!
First, The Edelbrock I have was on my old engine (350 worn out) The hotter it got, the crappier it ran! Same edelbrock, New 350! The hotter it gets (and man it gets HOT!!) the problems start!
I did purchace a Metering rod/jet kit from auto parts (expensive) I have changed my rods according to the book. Had to go leaner with the new engine. Set the floats, While I was taking the carb apart to see boiling gas in the bowls, a good friend and Chevy expert (corvettes) noticed that when I put the manifold on (old, from previous engine) I did not put the exhaust block-off plates in the center of the gaskets! He informs me that this is used to heat up the stock cast iron manifold, and really isn't needed for an all aluminum manifold. Quick fix was to do the 1" fanolic spacer which screwed up all my linkage adjustments but I am having much better acceleration without bogging, but I still have flooding (Hot days here in Florida) which I took a look at my gas line routing and made major changes to that as well as puting a rubber hose over my 5/16" fuel line to (I hope) insulate it. If this doesn't work, I am planning on going the old route of putting wooden clothespins to act as a heat sink on the fuel line! This aids in vapor lock as well as keeping the gas temp down so the gas doesn't expand and "push it's way into the carb and past the needle & seat to flood the carb.
I plan on removing my intake and re-doing it with the block-off plates installed this time! I remember throwing away those plates and wondering what they were for. I also remember that my old engine also didn't have these plates installed eithor! Remember, in both my cases the hotter it got, the crappier it ran! Maybe we should all look at this situation and see if all of you guys are having these heat related problems because of these block off plates!
Believe me, I am not an expert, just trying to learn what does what, when!

BFS58

[GPster]

There seems to be a lot of talk about "vapor lock" with this problem. I read a discription and reason for this problem in (of all places) a bout about updated electrical wiring in older cars. The author is highly respected in his field and ours and had been a part of restoring an old caddy so the queen of England could make a return tour of Canada. It seems when you substitute new blends of gasoline, more efficient fuel pumps and the demand for more flow a lot of the problem is the size of the fuel line. Pushing the gas from the tank and pressurizing the fuel line is part of the cure because the newer blends of gasoline are so volitil that under the low or negative pressure in the lines from the sucking of the old style pumps it doesn't take much heat to actually cause the gas to flash (vaporize) in the fuel line. The problem gets worse if the demand for flow is increased. You need to look at the whole system and chose what you will start to modify to prevent it. If you have boiling gas in the float chamber of a carb it may be because of heat in the manifold or it may be because the line was hot delivering gas to the carb or that the pressure on the gas in the lines to the carb was so high that release of thepressure to atmosheric pressure cause it to flash. Too bad I didn't realize any of this stuff when I was running a 392 "Hemi" with a Carter Series "E" AFB off a 5/16" fuel line. Of course those were the days of $.42 a gallon gas and $1.50 minimum wage. GPster

[47convert]

I don't think my problem has anything to do with heat because it sometimes floods when cold starting and sometimes when it's warm, but it always startd - just dumps a lot of black smoke out the pipes. And the gas mileage is real bad - I'm going to install a fuel pressure regulator today and see if that makes a difference. Thanx

[C9]

Set the carburetor up as Edelbrock recommends.

Go here for the info: http://www.edelbrock.com/automotive/eps_intro.html


I set up my Edelbrock 750 for the 3300' altitude where I live now following the chart.
The metering rod springs were also changed to pink and that's all that was done.
The carb works great.  (32 roadster with 462" Buick, mild cam, good ignition etc.)

Summit more than likely will have the parts you need and it only takes a couple of days to get them.

Aside from that, it sounds very much like you could have a bent metering rod and it's stuck in the up position.
Pull the metering rods and roll them on a known to be flat surface to check for any subtle bending.  (A plate of thick glass works fine for this, just leave the short bent piece hanging over the edge while you roll the rod.)
You can straighten rods by hand, but be very careful, it doesn't take much to bend them.

If you're running any kind of cam the vacuum levels will be lower than stock and that will pull the rods up and at idle and low speeds - when they should remain down - and feed excess fuel to the engine.
Vacuum pulls the rods down and the springs raise them up.
As you can see it's a bit of a balancing act.

Get a metering rod spring assortment from Summit or Jegs or wherever - usually $7.  or so for an assortment of five pair.
Give the orange springs a try and if there's a bog transitioning to the secondaries use the pink spring - or whatever spring your vacuum gauge tells you to use.

Engines in good condition with stock cam or very mild cam will idle 17-19" vacuum.
An engine with a 280 degrees (advertised duration) will idle 10-12" vacuum.

Store your used springs in a clearly marked container because the paint comes off them after a short while and they're impossible to identify with a good degree of accuracy.

[47convert]

Great info! Thanx