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Carb Tuneing
Posted By: Moparnut426
Carb Tuneing - 10/11/11 07:20 PM
Well I did some tuneing on the Demon this noon. First off, my secondary float was high, Like almost a full turn to get it back down to where is should be. 2nd, I had the idle adjustments off, and 3rd Ill have to set the timing down a smidge, it did a very slight diesel 1 time when I shut it down. I think Im at 34* now, Ill take it down to 32 or so and see how it acts.
I did notice the 408 never really reacted when I turned the idle screwes inn. Shouldnt it almost die whe the screwes are turned inn?
Could this mean my idle it soo high?
Kasey
Posted By: Mr.Yuck
Re: Carb Tuneing - 10/11/11 07:35 PM
I'd probably turn the screws all the way in then back out 1.25 turns, then fire it up to 2400rpm set your timing, then back it down to 8-900 and set your mixtures and go from there. 34* seems like it would be low enough
Posted By: Moparnut426
Re: Carb Tuneing - 10/11/11 07:36 PM
Ill try that. Couldnt hurt.
Kasey
Posted By: joedust451
Re: Carb Tuneing - 10/11/11 07:39 PM
Yes it should die when 1 is turned in, sounds like the transfer slots are too exsposed & its entering the main metering, in any case its getting too much fuel at "idle".
Posted By: Moparnut426
Re: Carb Tuneing - 10/11/11 07:53 PM
So how do I adjust it out of that if its past the idle cuircut
Kasey
Posted By: sixpackgut
Re: Carb Tuneing - 10/11/11 09:15 PM
set the transfer slots for both pri and secondary then start the engine. to adjust idle rpm, use your timing and not the screw on the side to raise and lower your idle rpm. adjust AF screws. readjust timing. recurve dist. done
if you have a msd dist, i dont think you can recurve easy like a mopar one because they suck
Posted By: joedust451
Re: Carb Tuneing - 10/11/11 10:28 PM
Quote:
set the transfer slots for both pri and secondary then start the engine. to adjust idle rpm, use your timing and not the screw on the side to raise and lower your idle rpm. adjust AF screws. readjust timing. recurve dist. done
if you have a msd dist, i dont think you can recurve easy like a mopar one because they suck
MSD dist. suck 
, Don't know which one you say is hard to dial in 
. I loved mine on my SB, i'll NEVER use a MP dizzy again, there a big PITA IMO with sloppy shafts too boot.
This is the one i use & its simple/simple/simple, just need an aftermarket box, but who cares everyone gets them anyways, The MP boxes suck, at least the orange units.
http://www.jegs.com/i/MSD+Ignition/121/8534/10002/-1
Posted By: joedust451
Re: Carb Tuneing - 10/11/11 10:38 PM
Quote:
So how do I adjust it out of that if its past the idle cuircut
Kasey
Square up the transfer slots on the primaries, even if its 4 corner idle the rear ones sit higher on the base, so you may never exspose them unless you open the butterflies more then the primaries, so start off with squareing up the front slots, then find out how far you needed to turn on the throttle screw to reach it, then open up the secondaries as much as the front, so if your primary throttle screw is 1.1/2 turns from fully seated, then set the back at 1.1/2 turns, then set all mix screws at 1.1/4 open, fire it up, make sure float level is good, set timing for highest manifold vacuum, then tailer in the mix screws & throttle shafts to obtain the best idle & the RPM where you want it. Hope this makes sence.
make sure the secondary idle is closed or it will pull fuel from there and the mixture screws will not kill the engine.
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 03:01 AM
Well I did all that and the idle screws are only about 1/4 to 1/2 out, and it dosnt die with them screwed inn. Do i need different idle air bleeds?
Kasey
Posted By: MR_P_BODY
Re: Carb Tuneing - 10/12/11 03:09 AM
Quote:
Well I did all that and the idle screws are only about 1/4 to 1/2 out, and it dosnt die with them screwed inn. Do i need different idle air bleeds?
Kasey
Did you have the transfer slots squared before you
tried to turn in the mixture screws... if they were
open to much you werent on the idle circuit
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 03:12 AM
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Well I did all that and the idle screws are only about 1/4 to 1/2 out, and it dosnt die with them screwed inn. Do i need different idle air bleeds?
Kasey
Did you have the transfer slots squared before you
tried to turn in the mixture screws... if they were
open to much you werent on the idle circuit
yes, I turned the carb over, squared up the slots, was pretty close to closed, wasnt opened very far at all, and I tuned it from there. still didnt die out after screwing them inn.
Kasey
Posted By: MR_P_BODY
Re: Carb Tuneing - 10/12/11 03:45 AM
Pull the mixture screws and blow out the ports with
a air nozzle/blow gun then try it again
Posted By: sixpackgut
Re: Carb Tuneing - 10/12/11 03:53 AM
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Well I did all that and the idle screws are only about 1/4 to 1/2 out, and it dosnt die with them screwed inn. Do i need different idle air bleeds?
Kasey
Did you have the transfer slots squared before you
tried to turn in the mixture screws... if they were
open to much you werent on the idle circuit
yes, I turned the carb over, squared up the slots, was pretty close to closed, wasnt opened very far at all, and I tuned it from there. still didnt die out after screwing them inn.
Kasey
fuel is getting in the motor from somewhere. if it was me, i would take the carb off, completely drain it and blow air into the little hole under the throttle blades and see if you feel air comming out the airbleeds with the mixture screw all the way in or its getting alot of fuel out of the transfer slot.
check to make sure you dont have a blown PV also
Posted By: Crizila
Re: Carb Tuneing - 10/12/11 04:01 AM
I had similar issues with my 750 mighty demon with "idle-Eze". 1. Try dropping the float levels a little more. 2. Make sure the idle air bleeds ( outers ) are the correct size. Mine were supposed to be .070" per the spec. Actually mic'ed .067". When I corrected that, I could kill the motor ( barely ) when I turned the mixture screws all the way in. Idled best with the mixture screws 1/2 turn out. BTW, you only want to "square" the transfer slots on the primary side. Secondary butterflies should be set to the bottom of the transfer slots ( not visible from the underside at idle. If you have "idle-eze", base line it at 1 1/2 turns out.
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 04:01 AM
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Well I did all that and the idle screws are only about 1/4 to 1/2 out, and it dosnt die with them screwed inn. Do i need different idle air bleeds?
Kasey
Did you have the transfer slots squared before you
tried to turn in the mixture screws... if they were
open to much you werent on the idle circuit
yes, I turned the carb over, squared up the slots, was pretty close to closed, wasnt opened very far at all, and I tuned it from there. still didnt die out after screwing them inn.
Kasey
fuel is getting in the motor from somewhere. if it was me, i would take the carb off, completely drain it and blow air into the little hole under the throttle blades and see if you feel air comming out the airbleeds with the mixture screw all the way in or its getting alot of fuel out of the transfer slot.
check to make sure you dont have a blown PV also
Ill do that again. I have a new PV inn it. Ill check to make sure they are clear.
Kasey
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 04:04 AM
Quote:
I had similar issues with my 750 mighty demon with "idle-Eze". 1. Try dropping the float levels a little more. 2. Make sure the idle air bleeds ( outers ) are the correct size. Mine were supposed to be .070" per the spec. Actually mic'ed .067". When I corrected that, I could kill the motor ( barely ) when I turned the mixture screws all the way in. Idled best with the mixture screws 1/2 turn out. BTW, you only want to "square" the transfer slots on the primary side. Secondary butterflies should be set to the bottom of the transfer slots ( not visible from the underside at idle. If you have "idle-eze", base line it at 1 1/2 turns out.
Ive done this, and also have 70s on the idle air bleeds.
The screws are about 1/2 out now but wont kill it off. Heres a thought just popped inn my head. Is it suposed to die individually, or when all of them are screwed all the way inn.
Kasey
Posted By: Bob_Coomer
Re: Carb Tuneing - 10/12/11 05:09 AM
Hey Casey
Does it have a idle speed screw on the back throttle shaft, most 4150's dont but some HP series do. Some you can adjust with the carb off on the bottom side of the base with a small set screw. You can turn it in a 1/2 turn or so. This will help give the engine some extra air without being so much in the front transfer slots. Thats why you see lots of old holley out there at the swap meets that have holes drilled in the butter flies. If you dont care to do this, this still might be a option, you can get replacement butter flies cheap if you want to go back so..
Make sure the floats are close, back the idle speed screw all the way out, then turn the idle mixture screws out about 1 1/2 to 1 3/4 turns from a light seat. This is probably hair fat but should provide a base line to adjust from. Turn the idle speed screw in to it just touches the cam, then turn in 1/2 turn see if it will idle, if it wont turn it in another 1/4 turn and try again.
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 01:57 PM
There isnt a screw on the back throttle blades, but there id a stop. I was thinking I may tweek that stop and get the rears to open a bit more.
Kasey
Posted By: justinp61
Re: Carb Tuneing - 10/12/11 02:15 PM
Kasey, what carb do you have? I have a Quick Fuel Q-750 that I had to drill the primaries to clean up the idle. I tried larger idle air bleeds, adjusting the idle screw on the secondaries and timing, but the thing that helped the most was drilling holes in the primaries. I'd only do this as a last resort.
BTW, in my experience if the secondary idle is opened to far the engine will surge at cruise speed.
You should be able to kill it with one air mixture screw.
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 02:19 PM
Well I guess Ill drill the primaries. What is a good starting point for the drill size? I have a small pinvise, and some torch cleaning drill bits, so I do have some very small drill bits.
Kasey
Posted By: sixpackgut
Re: Carb Tuneing - 10/12/11 02:30 PM
Quote:
Well I guess Ill drill the primaries. What is a good starting point for the drill size? I have a small pinvise, and some torch cleaning drill bits, so I do have some very small drill bits.
Kasey
i wouldnt drill anything yet. what exactly is the problem?
it is diesling after you shut off? to much air and fuel getting in the carb. drilling holes will make it rpm higher. you only drill holes if you have to open the throttle blades to far to get the idle rpm you desire
how is the fuel getting into the motor with the AF screws seated? this your problem. i would suspect they are not really seating. demon carbs have that funky bowl that goes over the metering block. is it stopping the AF screws from turning in all the way?
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 02:41 PM
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Well I guess Ill drill the primaries. What is a good starting point for the drill size? I have a small pinvise, and some torch cleaning drill bits, so I do have some very small drill bits.
Kasey
i wouldnt drill anything yet. what exactly is the problem?
it is diesling after you shut off? to much air and fuel getting in the carb. drilling holes will make it rpm higher. you only drill holes if you have to open the throttle blades to far to get the idle rpm you desire
how is the fuel getting into the motor with the AF screws seated? this your problem. i would suspect they are not really seating. demon carbs have that funky bowl that goes over the metering block. is it stopping the AF screws from turning in all the way?
This is a quick fuel holley, not a demon. Its on my demon though 
.
Everything seems to be ok, and nothing seems plugged. The problem is a rich idle. Will not propperly tune inn, and wont kill off when screws are turned inn telling me Im past my idle slots.
Im very close to going nutso here. Pluss ive set every carbon menoxid detector of in the whole city block it seems like. There was 3 of them going off in the shop last night. 
Posted By: sixpackgut
Re: Carb Tuneing - 10/12/11 03:00 PM
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Well I guess Ill drill the primaries. What is a good starting point for the drill size? I have a small pinvise, and some torch cleaning drill bits, so I do have some very small drill bits.
Kasey
i wouldnt drill anything yet. what exactly is the problem?
it is diesling after you shut off? to much air and fuel getting in the carb. drilling holes will make it rpm higher. you only drill holes if you have to open the throttle blades to far to get the idle rpm you desire
how is the fuel getting into the motor with the AF screws seated? this your problem. i would suspect they are not really seating. demon carbs have that funky bowl that goes over the metering block. is it stopping the AF screws from turning in all the way?
This is a quick fuel holley, not a demon. Its on my demon though .
Everything seems to be ok, and nothing seems plugged. The problem is a rich idle. Will not propperly tune inn, and wont kill off when screws are turned inn telling me Im past my idle slots.
Im very close to going nutso here. Pluss ive set every carbon menoxid detector of in the whole city block it seems like. There was 3 of them going off in the shop last night.
thats funny
take a pic of the throttle blades and transfer slots on the pri and secondary as you have it right now.
did you try calling QF?
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 03:22 PM
The last time I called QF, I got yanked around, first they told me it wasnt one of their carbs, then it was, then they couldnt help me without dyno numbers, yada, yada, yada. Ill call them again today.
Kasey
Posted By: Crizila
Re: Carb Tuneing - 10/12/11 03:33 PM
This post is starting to remind me of the Abbott & Costello gig - "Who's on first".
Posted By: joedust451
Re: Carb Tuneing - 10/12/11 05:20 PM
Kasey, Like i was telling you as we discused, Its deiseling do to a high idle, If you feel its rich & have pin drills, start opening up the 4 outer bleeds in .003" increments, Do not drill holes in the butterflies, that is a "last" resort, I'm sure the mix screws will start responding once you open up the IABs .003", those will be the outers, I'm guessing there .070", open them to .073", I had to open mine to .075" front & .073" back with my PF 750, The quik fuel is based on that floormat, Theres something else you need to check, make damn shure the gasket on the PV is not seeping, If there is a good seal on the MB & PV gaskets there should be no fuel behind the block in the "vacuum well" when you pull it off after draining, If its puddling in that area thats your problem, there should also be no heavy puddling in the intake, Have you checked the plugs too make sure there not foiling out, This also creats havick when trying to tune the idle.
Another thing you can do IF the IABs do not respond well, i had to do this on my PF, There are IFRs in the metering blocks, they should be screw-in bleeds, you can decrease that size by .003" on each (all 4). The carb can be tuned out for a clean idle without major headaches trust me, just some patiance & a general idea of what the engines telling you. BUT 1st. Make sure the plugs are fine & the PV/Bowl gaskets aren't leaking. DO NOT drill the butterflies just yet.
Posted By: sixpackgut
Re: Carb Tuneing - 10/12/11 05:26 PM
Quote:
Kasey, Like i was telling you as we discused, Its deiseling do to a high idle, If you feel its rich & have pin drills, start opening up the 4 outer bleeds in .003" increments, Do not drill holes in the butterflies, that is a "last" resort, I'm sure the mix screws will start responding once you open up the IABs .003", those will be the outers, I'm guessing there .070", open them to .073", I had to open mine to .075" front & .073" back with my PF 750, The quik fuel is based on that floormat, Theres something else you need to check, make damn shure the gasket on the PV is not seeping, If there is a good seal on the MB & PV gaskets there should be no fuel behind the block in the "vacuum well" when you pull it off after draining, If its puddling in that area thats your problem, there should also be no heavy puddling in the intake, Have you checked the plugs too make sure there not foiling out, This also creats havick when trying to tune the idle.
Another thing you can do IF the IABs do not respond well, i had to do this on my PF, There are IFRs in the metering blocks, they should be screw-in bleeds, you can decrease that size by .003" on each (all 4). The carb can be tuned out for a clean idle without major headaches trust me, just some patiance & a general idea of what the engines telling you. BUT 1st. Make sure the plugs are fine & the PV/Bowl gaskets aren't leaking. DO NOT drill the butterflies just yet.
if you can tell me what IFR you have in your blocks now, maybe i could trade you if i have smaller ones. they are the brass jets near the top corners
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 08:21 PM
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Kasey, Like i was telling you as we discused, Its deiseling do to a high idle, If you feel its rich & have pin drills, start opening up the 4 outer bleeds in .003" increments, Do not drill holes in the butterflies, that is a "last" resort, I'm sure the mix screws will start responding once you open up the IABs .003", those will be the outers, I'm guessing there .070", open them to .073", I had to open mine to .075" front & .073" back with my PF 750, The quik fuel is based on that floormat, Theres something else you need to check, make damn shure the gasket on the PV is not seeping, If there is a good seal on the MB & PV gaskets there should be no fuel behind the block in the "vacuum well" when you pull it off after draining, If its puddling in that area thats your problem, there should also be no heavy puddling in the intake, Have you checked the plugs too make sure there not foiling out, This also creats havick when trying to tune the idle.
Another thing you can do IF the IABs do not respond well, i had to do this on my PF, There are IFRs in the metering blocks, they should be screw-in bleeds, you can decrease that size by .003" on each (all 4). The carb can be tuned out for a clean idle without major headaches trust me, just some patiance & a general idea of what the engines telling you. BUT 1st. Make sure the plugs are fine & the PV/Bowl gaskets aren't leaking. DO NOT drill the butterflies just yet.
if you can tell me what IFR you have in your blocks now, maybe i could trade you if i have smaller ones. they are the brass jets near the top corners
Sixpack, Ill check. I wouldnt feel rght trading you as mine is a OLD QF and I dont have billet metering blocks.
Ill check it out though.
Kasey
Posted By: sixpackgut
Re: Carb Tuneing - 10/12/11 09:08 PM
do you have a drill bit set to measure your IFR's? what size is the carb?
Posted By: RobX4406
Re: Carb Tuneing - 10/12/11 09:20 PM
Initial timing setting... don't care about total at this point. IMO, street cars should never be timed based solely on a total number.
If it's 34 total and 6 initial, you're not going to have much luck. Not knowing the cam, most SB mopars I've ever been around like at least 12* initial and a few were in the 24 range.
Posted By: Moparnut426
Re: Carb Tuneing - 10/12/11 09:42 PM
Quote:
do you have a drill bit set to measure your IFR's? what size is the carb?
The carb is a 950hp from what QF told me. It has a 850 base plate and a 750 main body. The base plate measures slightly smaller than what an 850 should, but a lot bigger than a 750 base plate. Like I said this carb has me all confused.
Ill take it back appart and measure the meetering blocks for you guys.
Kasey
Posted By: Crizila
Re: Carb Tuneing - 10/12/11 11:52 PM
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Quote:
do you have a drill bit set to measure your IFR's? what size is the carb?
The carb is a 950hp from what QF told me. It has a 850 base plate and a 750 main body. The base plate measures slightly smaller than what an 850 should, but a lot bigger than a 750 base plate. Like I said this carb has me all confused.
Ill take it back appart and measure the meetering blocks for you guys.
Kasey
" Who's on first".
Posted By: Moparnut426
Re: Carb Tuneing - 10/13/11 05:13 PM
Here is my front metering block.
I havent measured the holes yet, but they are small.
Kasey
Posted By: Moparnut426
Re: Carb Tuneing - 10/13/11 05:15 PM
A second shot of it.
There was no signt of fuel puddleing behind the metering block at all.
Posted By: sixpackgut
Re: Carb Tuneing - 10/13/11 05:17 PM
Quote:
Here is my front metering block.
I havent measured the holes yet, but they are small.
Kasey
I bet those AF screws are not seating inside the metering block like they should
Posted By: Moparnut426
Re: Carb Tuneing - 10/13/11 05:19 PM
Should I invest in a set of billet blocks??
Kasey
Posted By: sixpackgut
Re: Carb Tuneing - 10/13/11 05:34 PM
Quote:
Should I invest in a set of billet blocks??
Kasey
no, nothing wrong with what you have. but those AF screws look like they would hit the little gaskets. get these
http://cgi.ebay.com/ebaymotors/BRASS-IDL...=item2568257bf5
Posted By: Moparnut426
Re: Carb Tuneing - 10/13/11 06:03 PM
I think I have a set of those on another carb. ill get them.
Kasey
Posted By: SCATPACK 1
Re: Carb Tuneing - 10/13/11 07:27 PM
Square up the transfer slots on the primaries,
This may be a silly question, but what does this mean when you say square up the transfer slots?
How do you do this?
thanks
Posted By: Moparnut426
Re: Carb Tuneing - 10/13/11 07:45 PM
Quote:
Square up the transfer slots on the primaries,
This may be a silly question, but what does this mean when you say square up the transfer slots?
How do you do this?
thanks
I finally figured it out from another member.
The transfer slots are about 1/8" long and a few thousands wide, and to square them up is to make a square out of them when view from the bottom of the carb. its only like 1/2 to 3/4 of a turn from dead closed to achieve this.
Kasey
Posted By: joedust451
Re: Carb Tuneing - 10/14/11 12:33 AM
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Here is my front metering block.
I havent measured the holes yet, but they are small.
Kasey
I bet those AF screws are not seating inside the metering block like they should
I agree, looks like it runs out of thread at the end & it has a thick boss, try some standard mix screws on all 4 corners.
Posted By: Moparnut426
Re: Carb Tuneing - 10/17/11 05:18 PM
Well after having my metering blocks out again, and talking with a tech guy at AED I think I may have either a warpped metering block, or a tiny crack where its pulling inn ectra fuel. So I ordered a set of Billet metering blocks from quick fuel. 93 bucks, and even if it dosnt cure my issue its not bad cash to spend on.
Kasey
Posted By: mopowers
Re: Carb Tuneing - 01/25/13 05:42 PM
Quote:
Well after having my metering blocks out again, and talking with a tech guy at AED I think I may have either a warpped metering block, or a tiny crack where its pulling inn ectra fuel. So I ordered a set of Billet metering blocks from quick fuel. 93 bucks, and even if it dosnt cure my issue its not bad cash to spend on.
Kasey
Did you ever get this figured out?