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(390 fe, hei dist with msd 6a, comp cams CCA-CL33-224-3, 7105 edel intake, 670 quick fuel brawler, fmx transmission) I recently put a new quick fuel carburetor on my engine after not being able to fix my off idle hesitation with a street avenger. The carb runs great except for it seems unusually rich at idle, it starts to chug some after a while at stop lights and it soots up the pipes and anyone behind me, its below freezing and I dont even need the choke to start it. It idles at the right rpm, 700 in park and about 500 in drive, timing is set around 16 at idle, which is what ran fine with the previous carb. I already increased the idle air bleeds from 27 to 31, and each of the 4 screws are 1 and a quarter turns outs. I know if it's rich i should move them in, but with already having bigger than stock air bleeds, I would assume they should be wanting to move out more. The transfer slots are set to a tad bigger than the stock adjustment, still mostly squares. I already replaced the power valve, it has a 7.5 while pulling about 14-15 vacuum. the floats arent too high either, set right in the middle. Any Ideas about this are appreciated, thanks.
 

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Decrease the size of the idle feed restrictions in the metering block, and then put the idle air bleeds back to what they were.

The Brawlers are intended for much more modified engines than what you have(bigger cams, single plane intakes) and will be stinky rich at idle and cruise on a milder cammed combination like yours.

You went from the badly lean at idle Avenger(what was Holley thinkin'??!!:rolleyes:) to a heavily rich idle racer carb....you went from one extreme to the other.
Your combination would likely have been great with the good old List #3310 Classic 750 Vacuum Secondary, and you wouldn't have had to fight with it.
 

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Your going all wrong with your adjusting your carb and you changed out the high speed or also called the main bleeds and they have no effect on idle as with the small size you posted all you did was slightly lean out the main circuit which does not go into effect until speeds over 40 mph and 2000 plus rpm at higher engine speeds to where there is enough air velocity to start pulling fuel from the boosters.

Post your complete engine specs such as compression ratio and heads and some other things. Also your timing might not be correct and that can effect things as well and I am not familiar with a Ford engine as I am a chevy guy but the same concepts apply to tuning and they still work the same. Also what vehicle is it in and also your carb is way out of adjustment with your idle mixture screws all out at 1 plus turns on all 4 idle mixture screws. I have dealt with 4 corner idle carbs a lot and when your idle circuit is calibrated correctly with correct timing on what your engine needs to run right the idle mixture screws will be about no less then half to no more then about 3/4 of a turn out on all four or 1 turn at the most but 90 percent of the time its between those numbers.

The 4 corner idle circuit carburetors are way more sensitive and will set differently vs a 2 corner idle circuit. What controls the calibration of your idle circuit and off idle circuit which is also known as the transition circuit if your idle air bleeds which should be around the .070 size and are the bigger outer air bleeds and also the biggest thing that controls how rich or lean your idle circuit is the idle feed restrictors in the metering blocks and I know most likely you have .033 in both front and rear metering blocks and depending on engine build on small blocks with mild cams in the [email protected] or less its on the too rich side but a big block would handle a richer mixture vs a small block since its a bigger engine.

The first thing is you need to verify your timing is correct on the initial timing and also what is your vacuum advance set on as is it on timed port or full manifold as that will effect things on your timing curve as well. What you would want to start off wise is have about at least no less then 12 degrees initial timing and also if you have an aftermarket distributor with an adjustable vacuum advance canister you want to adjust it to give no more then 12 to 14 degrees on the vacuum advance and hook it up to full manifold so it will give your engine more timing at idle so you would have 12 degrees initial for a starting point then if you have 12 degrees from your vacuum advance and put it on full manifold you will have 24 degrees of timing at idle and it will make your engine work better and also give your carburetor the proper timing it needs to be adjusted.

Also I don't know if your hei style distributor is the in cap design but if it is you need to limit your vacuum advance as msd makes a vacuum advance limiter plate so you can limit your vacuum advance from giving to much timing while cruising. You also want to have your mechanical advance start no earlier then about 1300 rpm or you can have an erratic idle cause of timing going in and out if you use really light springs. You would want a timing curve for the mechanical advance to start at about 1300 rpm then be all in around 3000 rpm or a little higher range.

You will want to check your initial timing with the vacuum advance disconnected to get that set and then when you go to check your vacuum advance timing you will have to hook it back up to full manifold to see how many degrees its adding and if its adjustable you want to set it to give you the 12 to no more then 14 degrees. If your balancer has timing marks it will be easier to set your timing. If you don't get a timing tape or look up on google and do a search on making your own timing tape and then you can set things. You also want to make sure that your TDC mark on your balancer is correct and lines up correctly with your timing tab.

After you do that then you need to reset your carburetor and make sure your not showing to much transfer slot on the primary butterflies as if you do then it will be running off the transition slot and not the idle discharge ports like it should be. You want to make sure your secondary side is open up at least a minimum of a 1/4 turn open but make sure its not open up to much to start off with. You want your primary transfer slot to be showing at least .020 and be open no more then .040 so it will be in the range that is good for the carburetor to idle well along with having the idle mixture screws to be able to adjust correctly to what will work best.

You will need to start from scratch and start over with things cause I can tell you now the idle mixture screws being that far out will foul your plugs and leave the black soot in your exhaust and cause a lot of problems. Get your timing checked first and then we can go from there and I can give a lot more information on setting up your carburetor and to what your looking for.
 

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Ok you got your initial timing right and I read to fast and like ericnova72 said your to rich on your idle circuit and you need to do is buy some idle feed restrictor blanks or a smaller size like .028 and you can drill them bigger if they need to be with a drill bit gauge set of a 61-80 size range. I would start with .028 idle feed restrictors in the front and rear as they have to be kept equal as that is how four courner idle carbs work vs a 2 corner. I had a small block once with a 228/[email protected] 547/547 lift hydraulic roller cam and I ran a 650 double pumper from quick fuel that was a brawler and I had timing set at 16 degrees initial with my vacuum advance of 12 degrees for a total of around 28 degrees combined at idle and I had my main idle set at about 900 rpm with my cam and I ran my 650 with .031 idle feed restrictors front and back and my idle mixture screws on all 4 screws was at 3/4 of a turn out and I had my primary butterfly setting between .020 and .040 thousandths and the secondary opening around a half a turn open and it ran well but that was a small block and a big block will slightly differ but you need to start off with a .028 size ifr and see how it does adjusting wise and if turns out to be to lean then you would move up to .031 and that would be leaner then what you currently got but a step up richer then a .028 ifr size front and back. They are a 6/32 thread size and you can get a ten pack from summit.
 

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Too much idle fuel, that cam doesn't need a carb with four corner idle.

There isn't any mandate that 4 corner idle have every idle screw adjusted the same number of turns, simply dial them back to give the engine what it wants. This can go as far as shutting the rears off and closing their butterflies.

The purpose of four corner idle carbs is to provide more idle air for big cams that need the engine turning 900 or higher RPMs to idle. This keeps from having to adjust on a primary only idle carb's throttle butterflies so far open the it ends up exposing so much transition slot that the carb causes engine stumbles as it is opened. This isn't that much cam, but I'll conceed it's getting toward that edge. Would not be a cam I'd use on an FE, the heads have terrible exhaust flow in the valves and ports let alone the rest of a convertional system, this is an engine that does better with a split duration cam. The Chevy guys are always whining about a poor flowing exhaust on the SBC, all I can say is, 'you ain't seen a poor flowing exhaust port till you've faced down a production FE head'. You best meet those heads with a die grinder in one holster and a set of early 427 exhaust valves in the other.

Anyway, you need to work on tuning the carb with out going crazy on air correction jets, one wonders why it is guys just bolt an Edelbrock on an engine and go to tuning the engine while Holley guys resort to all this jet manipulation to solve what should be simple tuning issues, certainly good for Holley's bottom line if nothing else. And I'm not trying to sell anybody on Edlebrocks, it's just an observation that guys runnng Holleys seem to abandon basic tuning practices and resort to all sorts of jet changing exersizes to solve basic and expected tuning issues. The Edelbrock is considerable more difficult to tinker with in this regard so the average guy just doesn't automatically resort to changing air bleeds, power valve and accelerating pump jets instead of getting the ignition advances set up correctly, plugs gapped properly, etc.

Some other things lead into this cam being on the high side of what a typical production converter wants for stall speed. Depending on what yours actually is combined with gearing and vehicle weight, this cam might want a little more freedom before facing the converter hooking up. This would allow more freedom with idle speed which in turn allows more base advance which the FE's crummy combustion chambers would like, so maybe the hot idle is more like 800 to 900 RPM out of gear with the in gear more like 700 to 750 using more base advance like 16 to 18 degrees instead of trying to use more idle air to speed the engine up.

Bogie
 

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On a 4 corner idle carb yeah its not etched in stone all the screws have to be equal but you don't want to shut off the secondary side screws all the way as that will make it way out of a good best tune in the first place and in my experience from very mild cams as little as 211/[email protected] all the way up to [email protected] and over cams regardless of what the specs are with proper timing and the proper idle circuit calibration with the best size ifr being equal front and back and keeping all the idle mixture screws all equal worked better then just closing off the rear and then opening them up say an 1/8 of a turn to still let some fuel in the rear and adjusting the primary side idle mixture screws more like it being a 2 corner idle then a 4 corner idle.

A 4 corner idle is better suited for bigger cams like stated but there is still no reason it can't be tuned for a milder cam by changing out the ifr sizes and that is just part of tuning beyond jets and power valves and the normal stuff.

Just like an edelbrock carb they all can be tuned to work right if one will learn how whatever style of carburetor they want to use functions and transitions from one circuit to another and learn advance tuning and there is nothing wrong with changing out the ifr size to lean it out and keep the four idle mixture screws balanced the same but that is just my two cents and experience as when it comes to hot rodding there are no complete etched in stone on carburetor tune and adjustment range to a certain degree but the four corner idle works better when set up correctly then just shutting the rears almost all the way and opening up the front ones more cause of it being on the too rich side in the first place.

That is what has worked for me but I have never worked with a big block engine before especially one like that one. But the same principals would still apply and I know other factors are there as well. I honestly like a 2 corner idle setup for milder cams vs a 4 corner when they are at least in the lower 220's @50 range but the 4 corner setup can still be used the same as on big cams just one needs to get it leaned out and that is why the stuff comes with changeable restrictors in the first place.

If one wants to you can make it a 2 corner setup by taking out the rear idle mixture screws and putting in some brass allen screws and then take the rear idle air bleeds down to a smaller size to compensate with there no longer being the idle mixture screws being there so its not way lean that point and put in around a .039 to .049 size and then it will be pretty much like what quick fuel does with there slayer carburetors that come as a 2 corner idle setup but the base plate and main body are already made as a four corner idle but they just don't have the rear metering block so they put in smaller idle air bleeds and a bigger size idle feed restrictor in the rear vs the front to calibrate it like holley does on there 2 corner idle vacuum secondary and smaller double pumpers.

Bottom line you can do several options and what ever is the easiest for you to do and get it to tune good and give your engine what it wants without it being to much or to little then as long as it is good with what it needs then its golden and tuned right for what it needs.

That is what is nice with the holley styles of the quick fuel carbs you can do a lot more with them vs the older holley brand names that don't have the changeable air bleeds and idle feed restrictors etc and give you the options without having to do your own customizing of things such as drilling and tapping the blocks.

I never really mess with changing air bleeds as I 95 percent of the time have left them be as they are and only have changed out the ifr sizes to make my engine get the idle calibration it wants without it being to rich or to lean and run right and cruise with no issues and have a proper idle setting and throttle opening etc. Edelbrock carbs are good as is others but they all have there pros and cons.

Yeah I am a holley carb guy but edelbrocks are a lot easier to tune on very mild builds for some people vs a holley without having as much knowledge on tuning them. Not saying anything that anybody is wrong as I am just sharing my experience with them in case somebody else would read this someday and use any information to maybe help themselves get a good tune. But in my experience changing out the idle feed restrictor sizes to either lean or enrichen the idle circuit is no different then changing the metering rods in an edelbrock to change the idle circuit calibration.

Just a different way of how to truly fine tune a holley style carb vs an edelbrock. On mild engines if you put the right out of box holley carb on it say a vacuum secondary like the street avengers then they bolt on and do pretty good without having to change anything on the idle circuits on mild engines but with a double pumper from holley or regardless if a vacuum secondary or a double pumper on the quick fuel and holley clones they are always going to be more rich out of the box as they are calibrated for engines with bigger cams and higher idle settings but no reason that they can't be tuned to run on a mild engine its just a different way of tuning them vs a edelbrock.

Most people who have holley style carbs never learn about how the idle circuit is setup and works and how it is tuned and many never learn how to tune that and they just move the screws in and out and try band aid fixes cause they are not being able to tune the idle circuit which accounts from idle to off idle while cruising through town and none of the literature that comes with those carbs explain anything about that vs an edelbrock that gives instructions on changing out the metering rods to make the idle circuit richer or leaner vs holley styles that gives nothing and that is why so many get caught up in doing things such as drilling butterflies with holes in them on cams that don't need holes drilled in the butterflies cause they don't have the right calibration on the idle circuit to begin with and that is where folks end up messing there holley style carbs up and have them all out of whack and then wonder why things are not running right even with the right timing curve and setup and good matching engine build.
 

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Wow, you guys have been talking a lot while I've been at work. Thank you for all the knowledge, everyone. First thing I did when I got home was went back to the original air bleeds, which were actually 28s not 27s. I turned in the idle screws a bit, and at exactly 3/4s a turn out on each it idles smoother than ever with no gas smell or tailpipe soot. I liked to think of myself as pretty experienced with tuning, but this is my first time with a 4 corner idle so I guess this was a good learning point.
 

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Too much idle fuel, that cam doesn't need a carb with four corner idle.

There isn't any mandate that 4 corner idle have every idle screw adjusted the same number of turns, simply dial them back to give the engine what it wants. This can go as far as shutting the rears off and closing their butterflies.

The purpose of four corner idle carbs is to provide more idle air for big cams that need the engine turning 900 or higher RPMs to idle. This keeps from having to adjust on a primary only idle carb's throttle butterflies so far open the it ends up exposing so much transition slot that the carb causes engine stumbles as it is opened. This isn't that much cam, but I'll conceed it's getting toward that edge. Would not be a cam I'd use on an FE, the heads have terrible exhaust flow in the valves and ports let alone the rest of a convertional system, this is an engine that does better with a split duration cam. The Chevy guys are always whining about a poor flowing exhaust on the SBC, all I can say is, 'you ain't seen a poor flowing exhaust port till you've faced down a production FE head'. You best meet those heads with a die grinder in one holster and a set of early 427 exhaust valves in the other.

Anyway, you need to work on tuning the carb with out going crazy on air correction jets, one wonders why it is guys just bolt an Edelbrock on an engine and go to tuning the engine while Holley guys resort to all this jet manipulation to solve what should be simple tuning issues, certainly good for Holley's bottom line if nothing else. And I'm not trying to sell anybody on Edlebrocks, it's just an observation that guys runnng Holleys seem to abandon basic tuning practices and resort to all sorts of jet changing exersizes to solve basic and expected tuning issues. The Edelbrock is considerable more difficult to tinker with in this regard so the average guy just doesn't automatically resort to changing air bleeds, power valve and accelerating pump jets instead of getting the ignition advances set up correctly, plugs gapped properly, etc.

Some other things lead into this cam being on the high side of what a typical production converter wants for stall speed. Depending on what yours actually is combined with gearing and vehicle weight, this cam might want a little more freedom before facing the converter hooking up. This would allow more freedom with idle speed which in turn allows more base advance which the FE's crummy combustion chambers would like, so maybe the hot idle is more like 800 to 900 RPM out of gear with the in gear more like 700 to 750 using more base advance like 16 to 18 degrees instead of trying to use more idle air to speed the engine up.

Bogie
At least for now it cruises like a dream, and I drive the thing everyday and everywhere, but it certainly aint fast. Somewhere down the line I'll get into the cylinder heads and I'll look into a more sensible cam. Doesn't seem like many people mess with FEs that much, thanks for pointing me in the right direction.
 

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I have a soft spot for FE's, kind of grew up on them as a young engineer and racer/hotrodder. I've done many ugly things to those heads. Today I'd just go to Edlebrock or Blue Thunder. They are not only aluminum but have modern chambers, which is something that really wakes these motors up while the aluminum knocks a lot of pounds off this porky engines and the chambers with the aluminum's fast heat transfer lets you boost the compression without pinging the thing to death. This works even better with a flat top piston, hints just incase you contemplate a rebuild. In the right hands these can become wicked motors but they aren't crazy about high revs about 6200 is the end of the safe zone, so building big displacement is the best bet unless you stumble into a NASCAR crank and rod set.

Bogie
 

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Past time to edit my last entry, but I just looked up on my desk top cabinet to see a blown 390 piston I use as pen and pencil holder along with some Harley Davidson, Boeing an NASA cups, and an Atomic Energy Commision glass ash tray that we fried in reactor a long time ago it used to be bright yellow but over the years has faded back to its original clear glass but the glass is changed it peels away in layers if you pick at it with your fingernail. Some of this stuff I've carted around for nearly 60 years. Time sure flies, seems like only yesterday us boys was in high school.

Bogie
 

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Glad you got it going better and love the history Bogie that sounds pretty cool :D. Those 4 corner idle carbs are so sensitive that just making an 1/8 of a turn makes a difference on the idle mixture screws to change things if its within good range on what the engine needs. On the older 2 corner style normally it takes over a 1/4 of a turn to get a change but it can differ at times depending on things. Keep at it and you will become a pro over time as with more experience it gets a lot easier and more simpler and less time consuming to tune those.
 

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I always enjoy hearing the history, too. I've just graduated high school myself, I got into these old engines and cars a couple years ago and I got some of my friends into it, too. The heritage in it and the experiences its given me are priceless. I've already done a couple garage rebuilds, but some more serious work and those cylinder heads will hopefully be soon to come.
 
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