Edelbrock carburettor problem.

ulwe · #1 (**permalink**) 09-26-2002, 02:52 PM

Im new to this forum.... but registered my cobra 2 years ago, and now after 10.000 kilometers, want to make some improvements. Does any of you have some tips about Edelbrocks carburettor? I have a 600 cfm manual choke, and this babe isnt soooo good. Originally the motor is leaning back/down by approx. 5 degrees but Ive put the engine in horisontal. This makes the carb tilt forward in the same amount. Now, when I brake hard and/or takes a sharp corner with the foot off accelerator pedal, engine stumbles or dies. I think it gets very rich and dies, I have black smoke when I start up again. So, is this flooding floats? What can I do? So far, I assembled an fuel pressure regulator and set it to 5 PSI with an minor improvement. HELP!

Ron61 · #2 (**permalink**) 09-26-2002, 03:15 PM

Ulwe,

I don't know much about the Idelbrock carbs as I have always used Hollys but there are guys here that are really good on them. You could contact Bill Emerson of Emerson Motorsports as that is what he uses an nearly every Cobra he builds. I am sure that Double Venom could also help you. sorry I can't be more help but it does sound like a float or air fuel mixture problem. I am not sure about the 5 pounds pressure as I run 7-9 pounds in my Hollys. Oops, almost forgot Mr. Fixit. I am sure he could probably give you some good ideas also.

Ron61
Ron Widener

flipper35 · #3 (**permalink**) 09-26-2002, 03:26 PM

Sounds like floats, but I am just saying that to keep near the top for someone knowledgable to respond.

scottj · #4 (**permalink**) 09-26-2002, 03:27 PM

Ulwe,

If the problem started after tipping the engine 5 degrees, then I would try a carb spacer milled at a 5 degree angle. A machine shop can make one using a gasket as a template.

Scott

JT · #5 (**permalink**) 09-26-2002, 09:57 PM

This does sound like a float problem-black smoke indicates a rich condition. I would suggest a carb rebuild with new needles & seats, and careful float adjustment. Remember, gasoline has lots of additives in it which eat up the seats quickly.
Now, just my opinion: I don't think changing the engine level would affect things too greatly, these cars operate at all sorts of angles. I may be wrong.

ulwe · #6 (**permalink**) 09-27-2002, 11:23 AM

Thanks Folks,
we have the same thoughts...... actually I dropped the intake manifold at a workshop on wednesday for milling to a parallell situation. I couldnt use a spacer due to limited space to the hood, I hope that I can squeeze in a 5 mm heat insulator after milling.
Carb was new, but OK, it has been sitting in petrol for 4 years now, could the needles already be finished? Saw an ad for off/road needles, better when floats are bouncing around? Does these have a spring that closes the needles?
Float adjustment I have tried (not carefully thou.....) only within Edelbrocks recommendations. Will make this again, when the carb is back on horisontal.
More ideas? If I cannot get this sorted out until winter, is next step to make an homemade injection system? My spine tells me there is more problems to discover in that area, than I can ever find in a carb...........

Ulf

concobra · #7 (**permalink**) 09-27-2002, 10:18 PM

Edelbrock carbs. are very sensitive to float adjustment. A 5 degree engine tilt could effect the conditions you are experiencing. As with any fluid, gas will move to the area/height of least resistance and under hard braking or cornering gas sloshes up the fuel circuit and into the manifold. Try setting the floats at the lowest possible level without running out of fuel during full throttle extended engine pulls. It's a matter of trail and error to get the level right.

As an example of this fuel overpull. Have you ever watched a carbed race car dive into a corner hard with heavy braking then upon exiting the corner the driver opens the throttle and a large flame shoots out the exhaust. This is caused by fuel sloshing up the main circuit and dumped into the manifold.

Hope this helps.

ulwe · #8 (**permalink**) 10-13-2002, 01:32 PM

Thanks,
your advice made it very OK!
My solution was to mill down my Edelbrock performer 289 intake, so the carb is in horisontal. I also made an heat insulator from "bakelit" 2-component hardened plastic, now we have 5 degrees celsius here, so this will be evaluated next summer. But with the horisontal position, it runs very OK now, next step will be to make my own, hand-made AFR gauge! Anyhow, I will try, and see if I can get it to work.

Many thanks,
Ulf

TFIVEUK · #9 (**permalink**) 11-16-2002, 07:35 AM

Don't mill the intake, the carb is supposed to run with a small degree of forward tilt - the problem you are experiencing is because the fuel level is to high in the bowls, remove the carb horn and adjust the floats to give a lower fuel level.
This exact problem is in the eddlebrock troubleshooting manual!

Roscoe · #10 (**permalink**) 11-16-2002, 08:10 AM

Ulf,
Here is the solution to your problem:

1) Disconnect throttle linkage
2) Disconnect fuel line
3) Remove 4 nuts holding carb to intake
4) Remove carb and THROW IT AWAY!
5) Buy a Holley, Demon or AED carb.

Roscoe

wadesdad · #11 (**permalink**) 11-17-2002, 10:29 AM

Roscoe,

You are flat WRONG!

My Edelbrock is more erratic than a non-medicated schizophrenic female with PMS. This winter when I replace my Edelbrock which has performed badly no matter what I do, I will NOT throw it away as you have suggested.

I will try to get the fuel smell out then use it as a nice office decoration - perhaps a large mobile of some sort. Then and only then can my automobile know how be displayed properly - the best Edelbrock is one off of the car.

-wadesdad

HighPlainsDrifter · #12 (**permalink**) 11-18-2002, 10:54 AM

It's too bad you last 2 guys never learned engine theory before opening your big hole, but then you just can't teach people who don't want to learn.

Mr.Fixit · #13 (**permalink**) 11-18-2002, 11:19 AM

Lower the rear fuel bowl float a tad. I bet that under braking, fuel in the rear bowl is overflowing through the bowl vent and choking the motor with too much fuel. I don't know the guts on edelbrock carbs, but if a vent baffle kit is available, get it, holleys always need them.

mikiec · #14 (**permalink**) 11-18-2002, 11:55 AM

From what I have read the Edelbrock has a problem with high speed turns. Something to do with the placement of the float, needle and seat placement.

Mike

TFIVEUK · #15 (**permalink**) 11-18-2002, 06:25 PM

The fuel bowls on the Edlebrock are on each side; the problem is quite specific and infact its not a problem at all; the fix is listed in the Carbs userguide and takes about 10 mins to do and a whole lot cheaper than ruining a perfectly good intake manifold by milling it which will cause cylinder distrubution problems.
Edlebrock are exceptionally good carbs; made by weber, they are just different to Holley's and therefore people don't understand them and think they are crap. The Edlebrock is quicker to callibrate than the Holley and probably better designed but If people can't be bothered to read the instructions then I guess there is no hope!
P.S. I run a Holley for authenticity but think an Edlebrock is better.

ulwe · #16 (**permalink**) 11-23-2002, 12:46 PM

Latest News:
The fuel mixture gauge is in the Cobra now, and it tells me what spark plugs and my nose already knew, engine is running fat.
This blacksmith type of intake manifold will NOT be ruined by milling it, trust me. After milling it is equal in height to the intake ports, so the small amount of unequality is actually removed, but hey were talking 1/2 inch improvement here. To work more on float optimizing will be more awarding!!!!!!! The fix is not to read the manual, friends, the fix is to use good advice from different sources together with your own personal filtering!!!
Ulf

HighPlainsDrifter · #17 (**permalink**) 11-23-2002, 09:43 PM

LOOK CLOSE.......on the driver's side of the Edelbrock carb.....
and you'll see WEBER ! That tells me that weber designed and/or engineered these carbs. So my dual 'WEBER' carbs are newer than the old downdrafts,but just as effective.
Perry.

wilf leek · #18 (**permalink**) 11-24-2002, 08:03 AM

Hmmm, might have a similar problem.

Although my Edelbrock carb runs just fineon the straights, it just will not behave in tight turns, engine always loads up.

I have tried dropping the fuel level to the point where the engine leans out on WOT. I even fitted the higher flow needle valves to make up for the lower fuel levels.
I have blocked the channel that runs between the two float chambers at the rear of the carb.

Still the engine bogs when the sideways forces come on. Anyone got any further ideas? And no, junking it for a Holley would not be a helpful suggestion!

Personally, I think the problem may be that the floats lock up on their pivots with enough lateral g??

Wilf

ulwe · #19 (**permalink**) 11-25-2002, 12:03 PM

Wilf,
maybe you have something there? Haven´t thought about that, but yes the floats could very well lockup sideways.
Those high flow needles, was it the off-road type or was it only the bigger type?
About the connecting channel, I think the purpose of it is to equalize fuel levels between chambers, one idea I have is to put open cell foam there to reduce speed of sloshing fuel but allow some fuel to pass by.
When I read a 10 years old magazine, an ad for "vaacum controlled fuel regulator" hit my eyes........... next words was "absolute MUST for Edelbrock carbs"!!!!!!!!
Anyone with experiences of this gizmo?

Ulf

Dirty Harry · #20 (**permalink**) 11-25-2002, 12:30 PM

I have an Edelbrock 600 which performs very well now. I had a bit of a stumble when accelerating from mid-range. I went to the Edelbrock website, clicked on their tech line, e-mailed my problem and, voila! That same afternoon, I received a reply which walked me through the solution. I would advise checking with the company for advice about their product. My experience with them was a good one.