off idle stumble with Edelbrock 750 -UPDATE -FIXED
#443767
08/19/09 11:20 PM
08/19/09 11:20 PM
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Joined: Aug 2005
Posts: 697 Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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I've recently replaced the intake and carb on my 1970 440 and have an issue I'd like some real world direction on before I tear into the carb. I had an Edelbrock performer RPM intake and a Holley 850 Double pumper on the car previously. The car ran well, and was great leaving a stoplight either in my neighborhood at low speeds or when moving off the line a little quicker This combo was really too tall for the stock hood and I wanted a more stock appearing engine compartment. I swaped in a 1971 square bore iron 440 intake and an Edelbrock #1411 750 cfm vac secondary carb. I'm OK with the overall performance of this combo as this car is a driver and I'm willing to trade maximum performance for street manners. The issue I have is an off idle stumble at light throttle; I need to give the car much more throttle to leave a stop smoothly than I did with the Holley. If I rev it up and slip the clutch more, it works great, but at light throttle it stumbles/bogs. I've been reading on the internet and this seems to be a fairly common issue with this carb on larger displacement engines. Has anyone had real experience with these, I just wanted a reality check before I go tearing into this carb and spend a bunch of money and time for marginal results! Thanks! Scott
Last edited by 70Sbird; 09/08/09 08:38 AM.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: racincuda]
#443769
08/19/09 11:34 PM
08/19/09 11:34 PM
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Joined: Jul 2006
Posts: 4,319 Puyallup, WA
StealthWedge67
master
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master
Joined: Jul 2006
Posts: 4,319
Puyallup, WA
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Not that it can't work, but you are in a long list of guys that have faught with the Eddy 750 off-idle stumble. Do a search on it, you'll be amazed. I tried every setting and rod / jet combo immaginable. Tried two different carbs, same issue with both. Went to a Holley 750, Sooooo much better.
LemonWedge - Street heavy / Strip ready - 11.07 @ 120
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: 70Sbird]
#443771
08/19/09 11:44 PM
08/19/09 11:44 PM
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Joined: Feb 2003
Posts: 10,294 Someplace you aren't
SomeCarGuy
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 10,294
Someplace you aren't
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Is it a new carb?
Might just be a weak accel pump not shootng out fuel right away.
Look down in the carb and move the throttle, see if fuel comes out right away.
I want my fair share
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443774
08/19/09 11:55 PM
08/19/09 11:55 PM
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Joined: Jan 2005
Posts: 2,179 S.E. Conn
Hoof Hearted
top fuel
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top fuel
Joined: Jan 2005
Posts: 2,179
S.E. Conn
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I have been through this personally with a couple of Eddy 750's and I have a solution that Does Work! 1) Verify that your floats are set properly 2) Try different springs for a quicker opening of the needle. 3) Verify that your accelerator/plunger is good(replace if any doubt) 4) Adjust the linkage that operates the accelerator; There's 3 settings, I believe the arm should be in the top hole. 5) Finally, the thing that most guys won't try: Remove the Primary Squirters and drill them out very, very slightly(get some tiny, tiny drill bits). Don't be afraid to try it. The last one is what did it for me. Let us know how you make out.
2005 300C Hemi 2014 Ram ProMaster 2500
I Rekey, Repin old Chrysler locks and cut keys by code
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Hoof Hearted]
#443775
08/19/09 11:59 PM
08/19/09 11:59 PM
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Joined: Aug 2005
Posts: 697 Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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Quote:
I have been through this personally with a couple of Eddy 750's and I have a solution that Does Work!
1) Verify that your floats are set properly
2) Verify that your accelerator/plunger is good(replace if any doubt)
3) Adjust the linkage that operates the accelerator; There's 3 settings, I believe the arm should be in the top hole.
4) Finally, the thing that most guys won't try: Remove the Primary Squirters and drill them out very, very slightly(get some tiny, tiny drill bits).
The last one is what did it for me.
Let us know how you make out.
so you're suggesting drilling out the accelerator pump shooters slightly? I can do that fairly easily! the kit they sell has three sizes and maxes out at .043" compared to the .035 on there now
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: 70Sbird]
#443777
08/20/09 12:14 AM
08/20/09 12:14 AM
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Joined: Jan 2005
Posts: 2,179 S.E. Conn
Hoof Hearted
top fuel
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top fuel
Joined: Jan 2005
Posts: 2,179
S.E. Conn
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yep. Start small, it don't take much out initially and be sure to follow/drill straight thru. (No coke bottleing at the end) Instantly noticable improvement. You made it clear your wishes were to stay stock looking and have more clearance. You Were Clear on this point. Yet the usual Anti-Eddy/holley-rules crowd had to ignore your preferences. I love Moparts, don't you?
2005 300C Hemi 2014 Ram ProMaster 2500
I Rekey, Repin old Chrysler locks and cut keys by code
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: SomeCarGuy]
#443779
08/20/09 08:02 AM
08/20/09 08:02 AM
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Joined: Oct 2003
Posts: 7,506 Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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Get the tuning kit for that carb and follow the booklet instructions that came with that carb and you should be able to easily fix your off idle stumble problem. These are some of the easiest carbs I know of to tune, and the booklet makes it a no brainer. Edelbrock did their homework. For your application you shouldn't have to modify anything on the carb to get it to work well. Per many good comments on this thread, make sure the carb is healthy to start with - good pump diaphram, floats set properly, etc, then just make changes to the rods, springs, jets, pump rod, per the booklet ( calibration reference chart )and you should be good to go.
Fastest 300
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Crizila]
#443780
08/20/09 09:06 AM
08/20/09 09:06 AM
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Joined: Aug 2005
Posts: 697 Central IL
70Sbird
OP
mopar
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OP
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Central IL
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Thanks for the feedback, I guess I should clarify, I want a stock appearing engine compartment with the stock air cleaner and coil location, those were not options when I had a dual inlet holley and tall intake.
Last edited by 70Sbird; 08/20/09 09:07 AM.
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Crizila]
#443782
08/20/09 09:50 AM
08/20/09 09:50 AM
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Joined: Aug 2005
Posts: 697 Central IL
70Sbird
OP
mopar
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OP
mopar
Joined: Aug 2005
Posts: 697
Central IL
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"Pretty, but can it fight." Stock appearing ? - "CAT" on the side of your battery aint workin.
You have to understand this car is a driver that is still in the process of becoming a complete car from the abandon project in boxes and pieces that it was when I purchased it a few years ago, I'm just trying to do this one step at a time, and I already had the battery!
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: 70Sbird]
#443785
08/20/09 10:56 AM
08/20/09 10:56 AM
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Joined: Jul 2005
Posts: 1,770 Wethersfield,CT
Ray440
top fuel
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top fuel
Joined: Jul 2005
Posts: 1,770
Wethersfield,CT
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Has anyone tried this before? Below the accelerator discharge squirter there is a small weight and a check ball. Buddy of mine had removed the weight and his stumble is gone. Leave the check ball in.
1969 Plymouth Road Runner 440 auto 2017 Ram 1500 Quad Cab 5.7 Hemi
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Re: off idle stumble with Edelbrock 750 - suggestions?
[Re: Ray440]
#443786
08/20/09 02:43 PM
08/20/09 02:43 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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Quote:
Buddy of mine had removed the weight and his stumble is gone. Leave the check ball in.
That would make sense as the weight would take up space & interfere w the flow, then if you dial in your shooter nozzle dia
Last edited by RapidRobert; 08/20/09 02:44 PM.
live every 24 hour block of time like it's your last day on earth
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