Moparts

Edelbrock of idle stumble 440 engine

Posted By: fury4speed

Edelbrock of idle stumble 440 engine - 10/19/16 02:13 AM

This is pretty much a unmodified engine , a mild cam and a dual plenum intake , the spark plugs look good , not wet or black , I want to mess with the metering rods to try and cure a off idle stumble , this is a Edelbrock 600 CFM , any suggestions? thanks.
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/19/16 02:55 AM

what's the initial? ported or manifold? Is AP tip in immediate/adequate volume? does it do it when fully warmed up? idle vacuum? what springs are in there? float level at 7/16 or slightly lower (richer)? they (the 1406) are lean & I would purchase the strip kit
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 10/19/16 03:25 AM

Start by moving the accelerator pump rod to the hole closest to the air horn in the accelrator pump rocker link.
Doug
Posted By: Jim_Lusk

Re: Edelbrock of idle stumble 440 engine - 10/19/16 03:28 AM

Manifold vacuum at idle?
Posted By: fury4speed

Re: Edelbrock of idle stumble 440 engine - 10/19/16 04:21 AM

I have the strip kit , it is a model 1311 750 CFM , I looked up the number , the accelerator pump rod is on the position that you mentioned , will check the manifold vacuum , thanks.
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/19/16 04:25 AM

and the initial
Posted By: bobby66

Re: Edelbrock of idle stumble 440 engine - 10/19/16 04:31 AM

Ignition first, then fuel. What's the initial timing?
Posted By: John_Kunkel

Re: Edelbrock of idle stumble 440 engine - 10/19/16 05:17 AM


IMO, off-idle stumble is the hallmark of the Edelbrock...running the idle mixture a little over-rich helps more than the other solutions.
Posted By: TJP

Re: Edelbrock of idle stumble 440 engine - 10/19/16 04:38 PM

I am surprised no one has asked where the primary throttle blades are with respect to the off idle transfer slots. If they are open too far it will create a stumble that will drive one nuts trying to correct the issue. shruggy
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/19/16 05:03 PM

see if you have a "square" or very close to that
Posted By: dogdays

Re: Edelbrock of idle stumble 440 engine - 10/20/16 12:17 AM

Also begin saving your pennies and dimes for a different carb. At least half the 750 Edelbrocks out there have a pretty incurable stumble. They are famous for this.

When the inevitable post comes along after me saying "I run 10s with my Edelbrock 750" you can sell yours to him. It never fails. During the time that I was buying carburetors from Ebay I noticed that the 750 Edelbrocks were selling for less.

R.
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 10/20/16 12:32 AM

Originally Posted By dogdays
Also begin saving your pennies and dimes for a different carb. At least half the 750 Edelbrocks out there have a pretty incurable stumble. They are famous for this.

When the inevitable post comes along after me saying "I run 10s with my Edelbrock 750" you can sell yours to him. It never fails. During the time that I was buying carburetors from Ebay I noticed that the 750 Edelbrocks were selling for less.

R.

Does yours run 10's with a Holley? Just wondering. Nothing is incurable, just hasn't had the correct fix applied. If the car stumbles it's either rich or lean at the hit. Determine which it is and correct the issue.
Doug
Posted By: 451Mopar

Re: Edelbrock of idle stumble 440 engine - 10/20/16 02:19 AM

When mine had an off idle stumble, the fuel level was too low in the bowls. Adjusting the floats for more fuel in the bowl fixed the problem.
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 10/20/16 04:04 AM

read this https://board.moparts.org/ubbthreads/ubbt...s-800cfm-14ough
Doug
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 10/20/16 02:43 PM

My mild 440 also had a small stumble that was minimized by adding more initial timing (14 initial, 36 all in) and sitting idle mix to max vacuum. I alsobought the tuning jets and rods, installed a A/F bung and tuned to A/F. Then I swapped the 915 heads and iron intake with Eddy Performer heads and a CH4B manifold. Car starts and runs/pulls hard. But when I stomp on the gas it goes completely flat/lean for a sec, then must get a burst ofgas and goes balls out.. It makes me lurch forward it is so bad. I bought and installed the .043 squirter and a new accelerator pump,but have not tested it yet.

I am ready to buy a Quickfuel 750 and be done with it, but am bummed as I have the finelines stock fuel lines..

Good luck solving yours. Check initial and idle mix with vacuum gauge.
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/20/16 04:59 PM

Quote:
But when I stomp on the gas it goes completely flat/lean for a sec, then must get a burst ofgas and goes balls out..
I'm sure you've checked this but is the AP tip in immediate upon the slightest throttle movement? & of good duration and are you on ported for the vac can?
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 10/20/16 05:11 PM

Originally Posted By RapidRobert
Quote:
But when I stomp on the gas it goes completely flat/lean for a sec, then must get a burst ofgas and goes balls out..
I'm sure you've checked this but is the AP tip in immediate upon the slightest throttle movement? & of good duration and are you on ported for the vac can?

Yeah, my issue may be diff. than the ops. I saw a good stream of fuel before in carb before I changed the AP and squirter. I moved to teh closest hole to airhorn with no help. I have a vacuum secondary casrb. Vacuum is high at idle at 21.

Hopefully the op can lessen his issues with timing and A/F. There are just so many threads all over the internet with this issue and that these carbs aren't meant for modified engines..
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/20/16 05:34 PM

I would see what the squirt looks like in your driveway at the offending RPM that it does it out on the road. You wouldn't be under a load but it might show something, it has to be lean for a reason & you'd think it'd be a reasonably easy thing to pin down. my 1406 needed richening (rods/jets) & would bog cuz the choke came off to quick (& I'm talking normal driving
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 10/20/16 06:18 PM

Fury4speed: I am sort of a rookie and wouldn't have been able to tune mine without the A/F meter. I only had a bung on one side fo the exhaust and got a reasonable gauge, but it really helped guide me with the rods/jets. I had it pretty well solved until I switched heads and manifold.. Can you weld a bung in the collector?
Posted By: dogdays

Re: Edelbrock of idle stumble 440 engine - 10/20/16 06:41 PM

It's done all the time. I don't think the bungs cost more than a couple $$.

The O2 sensor on gasoline engines has an 18mm x 1.5 thread same as a spark plug. People have used spark plug "de-foulers" with the externally threaded part cut off.

What my car runs or doesn't run is off the subject. The OP is having problems which sound so familiar, there must be 1000 different posts about this issue. The ironic thing is, most street cars that can run 10s have a 3000+ stall speed torque converter. This means that the engine never sees the condition plaguing the half of 750 Edelbrocks that have the stumble, except maybe on the drive back to the pits.

When I wanted a big Edelbrock I took AndyF's advice and bought an 800.

R.
Posted By: fury4speed

Re: Edelbrock of idle stumble 440 engine - 10/26/16 04:25 AM

Here is what I did , it runs and there is no stumble off of idle , at all , this worked for me.

Drilled out the accelerator nozzles to .045 (went to .041 first)

Installed the .113 primary jets

Installed the .073 X .037 metering rods

Installed the stiffest metering springs
Posted By: 451Mopar

Re: Edelbrock of idle stumble 440 engine - 10/26/16 06:03 AM

Did you ever check the fuel level in the bowls?
I did the same thing you did, made the carb "work" with what should be a really rich setup. Then I adjusted the float level for more fuel in the bowls and had to back those changes out because the carb was too rich.
Posted By: RapidRobert

Re: Edelbrock of idle stumble 440 engine - 10/26/16 06:22 AM

its all good now but I'm wondering if drilling the nozzles is what did the trick
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 10/26/16 02:55 PM

Originally Posted By fury4speed
Here is what I did , it runs and there is no stumble off of idle , at all , this worked for me.

Drilled out the accelerator nozzles to .045 (went to .041 first)

Installed the .113 primary jets

Installed the .073 X .037 metering rods

Installed the stiffest metering springs

This is close to where I am at so I hope it runs once I finally get going.
Can you give a brief description of your motor specs/parts as it would help..
Posted By: fury4speed

Re: Edelbrock of idle stumble 440 engine - 10/26/16 03:19 PM

I changed the rods (smallest diameter that I had first and no change or big change that I could notice

I drilled out the nozzles to .041 next and that made a difference

I changed the springs to the weakest springs , made it worse (I guess that seemed to hold them down in the jets longer so maybe a lean condition

I change back to the strongest springs and that was better

I drilled out the nozzles to .045 and that helped a lot

I ordered a marine accelerator pump as I read where that makes a difference p/n is 1468 but it is still on the way here and I have not installed it

I guess it was a all around lean condition , the floats were fine and were at 7/16
Posted By: fury4speed

Re: Edelbrock of idle stumble 440 engine - 10/26/16 03:26 PM

Originally Posted By p d'ro
Originally Posted By fury4speed
Here is what I did , it runs and there is no stumble off of idle , at all , this worked for me.

Drilled out the accelerator nozzles to .045 (went to .041 first)

Installed the .113 primary jets

Installed the .073 X .037 metering rods

Installed the stiffest metering springs

This is close to where I am at so I hope it runs once I finally get going.
Can you give a brief description of your motor specs/parts as it would help..


The engine is a 440 , edelbrock intake and 1411 carburetor , cam is suppose to be a mild cam , I bought it this way so I have no idea what it is the engine.
Posted By: buildanother

Re: Edelbrock of idle stumble 440 engine - 10/26/16 04:48 PM

I put a quick fix on my stroker 500", edelbrock 800 carbed, 400 bb, by stretching the springs about 1/8". It helped lift the rods enough to lose the flat spot. I had tried all the pump settings beforehand.
Posted By: 74RALLYE

Re: Edelbrock of idle stumble 440 engine - 10/29/16 05:21 PM

I tried everything previously mentioned (except streach the springs) and I could not get rid of the off-idle dead spot. I even tried a new 800cfm after giving ip on the 750cfm. I also have a low vacuum cam that makes it worse in my 440. The only fix for mine was a different brand carb.
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 10/29/16 11:46 PM

Occasionally the idle circuit will not feed enough fuel depending on the combo. Opening the idle feed tubes will usually fix it.
Doug
Posted By: gdonovan

Re: Edelbrock of idle stumble 440 engine - 10/30/16 11:33 AM

Anyone looking to part with one of these troublesome 750 cfm devices drop me a PM. I'll install it on my Duster which has wide band and have a look see.

Gary
Posted By: 74RALLYE

Re: Edelbrock of idle stumble 440 engine - 10/30/16 03:43 PM

I sold the 750 already. I still have the 800 if your interested. $150
PM me if you want it.
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 10/31/16 06:35 PM

I am with you and mine may be for sale. Just instralled nue acc. pump and the 43 squirter to no avail. Either the butterflies/weights are not kicking in the secondaries soon enough, or there is another issue. I actually need to peer in and make sure not a mechanical issue there restricting the opening. They eventually open, jsut not right away..
Posted By: fury4speed

Re: Edelbrock of idle stumble 440 engine - 10/31/16 07:34 PM

I have read where the marine accelerator pump works better as the spring is stronger and will push more gas out of the nozzles without collapsing the stock spring , never tried it though , the part number is Edelbrock 1468 , mine is working a lot better now , virtually no hesitation of idle.
Posted By: Lee446

Re: Edelbrock of idle stumble 440 engine - 10/31/16 08:01 PM

I have finally ended up with one of these notorious carbs, never had any problems with the 600 and 800's that a little tuning did not straighten out.... till now. I acquired a brand new 1411 for free. I put it on a mild 440, 240@50 cam, Holley SD intake and proceeded to tune. Big off line stumble, the distributor needed more initial and a curve anyway, so I bought the plate kit from FBO that allows you to limit total timing in the older MP dist, without having to play the braze up the slot and file game. This thing is great and this particular engine is very happy with 20* initial, 34 total, and using the vac advance adjusted to add 10 at idle on the full time vac port as recommended by FBO. Before I got the plate , I had tried the .043 squirter,HP orange(marine) acc pump plunger, and played with the jet metering rod combos until its infamous off line bog was almost gone, but not quite! Getting all of the timing issues squared away finished it off and made the car a joy to drive under all conditions but one. If you are at a complete stop and floor the throttle, it literally dies! You can hit the throttle briskly and smoke the tires, ease into the throttle and spin tires, but if you mat it, it dies! Pump is at max shot, passages are clear, and it will die every time if you mat it from a standing start, if you are already moving, no problem! it is like it is going massively lean. The floats are perfect, I am frustrated as the devil! I can put the tuned 1406 6oo cfm carb on it and it will come off the line sideways, same with my 800 performer, but that ****###@@ 750 has me stumped. It works great except that one situation. No bog in any other form of accelerating, just full bore from a standing start! Any ideas on this one??? Lee.
Posted By: bee1971

Re: Edelbrock of idle stumble 440 engine - 10/31/16 09:55 PM

Just use the google search on top of the Moparts page and enjoy all the lovely threads on the 1407/1411 off idle stumble , and then sit back for a month reading all 10,000 threads on how to fix it

Do you own a drill , a reciprocating saw , hammer , open wallet , and have unlimited time on your hands ???

Perfect , then the 1407/1411 is the carb for you

LOL
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 11/01/16 04:29 AM

Have ANY of you ever tried drilling the idle feed tube, changing air bleed size? Or is it easier to give up and complain? People will change metering blocks, air bleeds, squirters, squirter cams in Holleys till they turn blue. Heaven forbid you try something on a Edelbrock besides squirters, springs, rods or jets. Think outside the box. If it's lean, richen it up. It's still just a carb. Is it a full race Holley, absolutely not. Can they be a decent carb, yes.
Doug
Posted By: max_maniac

Re: Edelbrock of idle stumble 440 engine - 11/01/16 02:36 PM

Originally Posted By dvw
Have ANY of you ever tried drilling the idle feed tube, changing air bleed size? Or is it easier to give up and complain? People will change metering blocks, air bleeds, squirters, squirter cams in Holleys till they turn blue. Heaven forbid you try something on a Edelbrock besides squirters, springs, rods or jets. Think outside the box. If it's lean, richen it up. It's still just a carb. Is it a full race Holley, absolutely not. Can they be a decent carb, yes.
Doug


iagree It's not rocket science. Look into almost all NSS cars and this is the carb they run and do not have these issues that every one is complaining about. I actually tried the 800's for the last 2 years and then decided to go back to the 750's as my 60 ft times were better and so was my ET. Had a small bog at first and lightened up the rear air doors and the bog is gone.
Posted By: bee1971

Re: Edelbrock of idle stumble 440 engine - 11/01/16 04:26 PM

I didn't realize the NSS cars leave the line "OFF IDLE"

Thanx for clarifying that

LOL
Anyways

I tried drilling the idle tubes on my 1407 - Didn't work or help or change anything

On the street , daily driver , "OFF IDLE" the Edelbrock 800 series AVS is 1,0000 times better the carb
Posted By: p d'ro

Re: Edelbrock of idle stumble 440 engine - 11/01/16 05:30 PM

Originally Posted By Lee446
I have finally ended up with one of these notorious carbs, never had any problems with the 600 and 800's that a little tuning did not straighten out.... till now. I acquired a brand new 1411 for free. I put it on a mild 440, 240@50 cam, Holley SD intake and proceeded to tune. Big off line stumble, the distributor needed more initial and a curve anyway, so I bought the plate kit from FBO that allows you to limit total timing in the older MP dist, without having to play the braze up the slot and file game. This thing is great and this particular engine is very happy with 20* initial, 34 total, and using the vac advance adjusted to add 10 at idle on the full time vac port as recommended by FBO. Before I got the plate , I had tried the .043 squirter,HP orange(marine) acc pump plunger, and played with the jet metering rod combos until its infamous off line bog was almost gone, but not quite! Getting all of the timing issues squared away finished it off and made the car a joy to drive under all conditions but one. If you are at a complete stop and floor the throttle, it literally dies! You can hit the throttle briskly and smoke the tires, ease into the throttle and spin tires, but if you mat it, it dies! Pump is at max shot, passages are clear, and it will die every time if you mat it from a standing start, if you are already moving, no problem! it is like it is going massively lean. The floats are perfect, I am frustrated as the devil! I can put the tuned 1406 6oo cfm carb on it and it will come off the line sideways, same with my 800 performer, but that ****###@@ 750 has me stumped. It works great except that one situation. No bog in any other form of accelerating, just full bore from a standing start! Any ideas on this one??? Lee.


This is mine to a tee. But mine dies flat from stop or while moving, then kicks in hard. A little scary as it breaks loose and gets a little wild. Probably won't address it til springtime.
Posted By: dvw

Re: Edelbrock of idle stumble 440 engine - 11/01/16 09:49 PM

Originally Posted By bee1971
I didn't realize the NSS cars leave the line "OFF IDLE"

Thanx for clarifying that

LOL
Anyways

I tried drilling the idle tubes on my 1407 - Didn't work or help or change anything

On the street , daily driver , "OFF IDLE" the Edelbrock 800 series AVS is 1,0000 times better the carb


Many do. Mine will, but for reaction time I leave higher.
Doug
Posted By: max_maniac

Re: Edelbrock of idle stumble 440 engine - 11/01/16 10:26 PM

Originally Posted By dvw
Originally Posted By bee1971
I didn't realize the NSS cars leave the line "OFF IDLE"

Thanx for clarifying that

LOL
Anyways

I tried drilling the idle tubes on my 1407 - Didn't work or help or change anything

On the street , daily driver , "OFF IDLE" the Edelbrock 800 series AVS is 1,0000 times better the carb


Many do. Mine will, but for reaction time I leave higher.
Doug


Most times I do leave off idle and still no issues. Like Doug I do get on the converter at times to adjust reaction times. In fact when I do leave off idle my 60 ft times are better as I flash the converter more. Just the RT thats different.
Posted By: gdonovan

Re: Edelbrock of idle stumble 440 engine - 11/03/16 12:40 PM

I figured a bunch of guys would get in touch with me to get rid of their troublesome 750's

A single board member has been in touch after a week.

Actually had enough time to dwell on it and considering fuel injection!

Just thought it was funny...
Posted By: second 70

Re: Edelbrock of idle stumble 440 engine - 11/04/16 05:40 PM

I have a 1407 I'll sell you that came off my hemi for $150. It"s in like new condition with all factory settings.

The same price I sold the other one to a friend who has it on his corvette.
Posted By: gdonovan

Re: Edelbrock of idle stumble 440 engine - 11/04/16 11:37 PM

Originally Posted By second 70
I have a 1407 I'll sell you that came off my hemi for $150. It"s in like new condition with all factory settings.

The same price I sold the other one to a friend who has it on his corvette.


I'm all set, picked up a new Carter Comp series 750 this morning off Ebay.
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