Holley Carburetor: Part 2 of Idle Circuit

In this video, we conclude the Holley Idle Circuit and mods

[@lonniepeek2685]

This guy really knows his stuff. He is such a good instructor and understands how carbs work.

[@holleycarbshowtosadvice40y90]

Thanks Lonnie.

[@rodneyf.9595]

Worked out well Randy thank you . I been building these for years and this helped my car so much !

[@holleycarbshowtosadvice40y90]

glad i could help Rodney , i have been modifing holleys for a long time and still get excited when i learn some thing new,ps nice lookin car.

[@IBMara]

Thanks. Very thorough and easy to follow.

[@holleycarbshowtosadvice40y90]

Thank you for watching.

[@patrickmontgomery6353]

I am so glad I found this channel. Those who are good, do. Those who are great, Teach. Those who can't, criticize and thumbs down. Thank you for sharing all your knowledge.

[@holleycarbshowtosadvice40y90]

Patrick I appreciate the kind words, and I hope this information helps you, leave me a comment if there is anything I can help you with.

[@Moparmaga-1]

Thanks Randy for sharing your knowledge

[@holleycarbshowtosadvice40y90]

Thanks a lot.

[@ITSNOTMEITISYOU]

Thanks Randy for taking your time to share the knowledge you’ve acquired thru experience. I’ve always had a saying that no body woke up one morning and knew everything they know. My second one is “you learn something new everyday if not you didn’t pay attention”. Well I have the privilege to pass my knowledge on as a carpenter to a young man that’s my helper every day. Just my way of teaching is I won’t answer the question but ask him questions till he answers his own that way has to apply different thought patterns on how to solve an equation. But the best way to learn is from someone who knows what their doing and to just get your hands dirty and tear into it! So thanks again I know that was long winded response there😂👍🏻👍🏻

[@holleycarbshowtosadvice40y90]

Your right , I hope we can teach the younger generation to repair , build and design things, I hope I never stop learning something new .

[@bertramlrezenet9311]

Keep up the good work Randy! You're doing an excellent job! 👍

[@irzoro]

Thank you Randy for sharing these two videos. These are the golden nuggets of expertise that are gained only through experience. Experience is something no school or university can teach, it must be earned through toil and time, trial and error...Thank you again sir!

[@TheMuncieracer]

What would cause the fuel to drip out of booster on a 1969 600 holley while trying to get it to idle ? Fuel level is set just below plug port. Will not idle because it's trying to flood out

[@TheMuncieracer]

I bought it and been all rebuilt

[@ITSNOTMEITISYOU]

Amen you are 100% correct

[@ITSNOTMEITISYOU]

@@TheMuncieracer make sure the air bleeds that are down in the body on each side of the boosters are clear. I believe he said the inner ones are for the high speed so if clogged it’s not controlling the signal loss to the boosters thus pulling the fuel thru. I really hope I’m not just speaking out my back side but I believe that is the circuit that would cause that to happen. Also check your fuel pressure but only if this doesn’t work. Good luck

[@holleycarbshowtosadvice40y90]

Any thing that restricts the idle circuit or the wrong main body to throttle plate gasket will cause this .

[@edgolding9962]

Very informative,learn a lot from your expertise . will do some trials on my carb , thanks for the video.

[@holleycarbshowtosadvice40y90]

Thanks Ed.

[@mattfountain2023]

Another great video! Thanks Randy!

[@holleycarbshowtosadvice40y90]

Thanhs

[@nepoleonbonaparte6517]

Very good info thanks look forward to watching more ..

[@holleycarbshowtosadvice40y90]

Thank you

[@tonylewis4392]

Excellent Randy You have a special gift of turning complex and annoying into simple and enjoyable

[@holleycarbshowtosadvice40y90]

Thank you, i really appreciate that.

[@imken2392]

Great videos...part 1 and 2. First person I've seen that actually addresses transfer port sync correctly. I'm going to tune a buddy's Demon tomorrow. The idle eze feature on them eliminates the need to drill the butterfly's to add more air.

[@holleycarbshowtosadvice40y90]

That is a great feature on the demons the new holley xp series has it too. I can tell you under stand what your doing, nice chatting with you.

[@carlpalmer1823]

great vidieo thanks for the info tried it on my carb and it works

[@holleycarbshowtosadvice40y90]

Thanks for watching

[@ab_customz_llc]

Got yourself another subscriber! Job well done Randy!

[@holleycarbshowtosadvice40y90]

Thank you

[@timdigstone]

I LOVE IT Randy!!!!

[@holleycarbshowtosadvice40y90]

Thank you

[@thesillybilly]

You two over there giving us instructional while your drinking????? Hell yeah!!! My kind of video!!!!

[@holleycarbshowtosadvice40y90]

Thanks

[@HotRodDave]

Great advise on carbs. I liked and subscribed

[@holleycarbshowtosadvice40y90]

Thanks Dave

[@deesel666ify]

Good stuff!👍 Appreciated!!

[@holleycarbshowtosadvice40y90]

Thank you

[@jimkillen1065]

Sir its been a long time ago and I was not sure that I had it right as it was around 40 years ago lol . I did not know about the mod to install the restrictor . I read about putting a piece of wire in the metering block .I read that in a hot rod mag . I really appreciate these videos . I had to make the mods to the engine when I went from a 4 speed to a automatic and make the motor idle proper

[@holleycarbshowtosadvice40y90]

Us old timers have to stick together lol.

[@flinch622]

Thanks for posting, Randy. Assuming no vacuum leaks (and heads are in good condition) the fix this offers is based on cam demands/behavior, and alot of folks reaching for a big cam need to look at this. About what level of manifold vacuum at idle would you look to do this mod? Your point about transfer slot exposure is spot on: having to crank butterfly's open just to maintain idle indicates something else needs attention. Also, have you ever had to resize the hole that cross connects transfer slot to idle port in extreme cases? As a side note, I've found small gauge pin sets need to be mic'd when first received for best confidence when mapping out a metering block before modifying anything - grabbing drill bits based on a pin that isn't as advertised loses time and gnashes a few teeth.

[@holleycarbshowtosadvice40y90]

i check all my guage pins for size and drill bits too ,also because its so easy to get them out of order,there are some that are more accurate than others, but they are expensive. if i feel i need more idle mixture i would modify it to a 4 corner idle circuit .nice talking to you.

[@garygarren7078]

I love it!!!

[@holleycarbshowtosadvice40y90]

Thank you

[@timgroleau1612]

Well done.

[@holleycarbshowtosadvice40y90]

Thanks Tim.

[@chriscurrie5238]

Great Video, thank you. I have a 390cfm 4160 vac secondary on a 215 and have an issue where to get cruise at 14.7:1 I have to set idle too rich at 12.3:1, if I set idle to 14.7:1 then slow cruise goes to around 16:1 and engine hesitate when accelerating from such lean conditions. I assume not much fuel is coming off the main jets at 1800rpm cruise conditions, so do I need to jet up the idle fuel restrictor a bit and then screw in idle screws a bit? Higher rpm cruise is around 13.8:1 so gets progressively richer at higher rpm. WOT is currently around 12.5:1. Also, could I just confirm what tap size you used as it sounded like you said 6/32" unf which doesn't sound right, just so I can order some grub screws before taking carb to pieces. Thanks Chris

[@holleycarbshowtosadvice40y90]

I would try larger idle fuel restrictor or a smaller idle air restrictor.

[@chriscurrie5238]

@@holleycarbshowtosadvice40y90 thanks for replying. Smaller main jets and setting idle around 14:1 seems to have sorted the issue.

[@howardpenland2647]

Hi Randy! Would like to see whats involved in transfering secondary transition slot screw from bottom of Holley 830 double pumper to the top of carb.

[@holleycarbshowtosadvice40y90]

Yes look at my videos I have one that covers it.

[@VeghTheHun]

I'm not sure of I missed it in the video, but when you tap the hole and install the plug screw in the metering block, are you doing this on both primary and secondary metering blocks? Also on both sides of the metering block?

[@holleycarbshowtosadvice40y90]

If you have a two corner idle circuit , then just the primaries, 4 corner idle circuit then primaries and secondaries , on the metering block that faces the main body there are two fuel restricters on the same side of the meter block install one on each idle fuel restricter circuit of the metering block this is a mod I make for racing engines with big cams usually.hope this helps.

[@donrutter6765]

I'm doing a 4778 700cfm and the metering plates dont even have brass orifices for the 2 holes next to the power valve. They are huge. I stuck a .017 guitar string in the 4 holes of front/back metering blocks, but I expect I will need to go bigger. Idle screws adjust out good @ 1 1/2 turns, 4 butterflies drilled, but just idles rich. Randy, I was wondering where you got the threaded plugs for the IFR's and whats the best way to drill them, I have a drill press.

[@holleycarbshowtosadvice40y90]

The guitar strings aren't going to fix it fine your idle fuel restrictor mabe located at the top of your metering blocks on the left or the right side there should be a screw in idle fuel restrictor .

[@russellmorrow6704]

Mr Randy i have a 600 with vac sec on my 350 chevy.its all stock.my problem is its seems slugish when i stomp it.ive adjusted it with a vac gauge.another problem im haveing is a hard start when warm.it usally starts up fine when cold but i have to spin it alot sometimes when warm.any advice would be great.thank you in advance.

[@holleycarbshowtosadvice40y90]

that could be a ignition timing issue , late initial timing or not enough advance due to stuck mechanical advance and vacuum advance . checking timing with a timing light, should see 35 to 40 degrees total timing at 3000 to 3500 rpms. hard start hot can be a lot of diffrent things could be a blown power valve in the carburetor or to much heat and gas boiling in carb hope this helps

[@nummerfinfeable]

Hey Randy...what do the numbers on the throttle plates mean?. brilliant videos, makes working with Holley`s a bit more less daunting.

[@holleycarbshowtosadvice40y90]

Think they may be an engineering number not sure. Sorry took so long to reply , must have been when we were having so much channel problems.

[@mikef-gi2dg]

The BAD A CARB MAN tackles idle circuit again! I don't think my mild SBC would ever need this mod, but I know where to go for the how to. I have not seen this detail anywhere else, period. Video info like this, makes me want to stay with the obsolete carburetor, and forget the EFI.

[@holleycarbshowtosadvice40y90]

Glad I could help.

[@mjess7934]

Thanks Randy for your technical advice on this problem. I did every thing you said Now I cant get the carb to idle down below 1800 rpms. What do you think it could be?

[@holleycarbshowtosadvice40y90]

Can you refresh my memory from the start, give me all your information. Thanks

[@backnine]

Hi Randy Good video. My metering block 2300 2 barrel on a 440 six pack center carb does not use the main well cross over system. It has idle pick up tubes that go into the top of the metering block into the main well. Is there a way to remove these tubes for cleaning or modify. I have tried to do this on scrap metering blocks of the same configuration and it did not work well. This is an area that will get gummed up and not feed fuel properly to the idle circuit. Also I have seen a lot of warped metering blocks over the years. Fuel will leak from the main to the power valve vacuum side and cause a very rich condition. Is there a way you check the sealing of the metering block to the body. I have filed down the face of the body to make it flat but have not figured a way to take the warp out of the metering block as of yet. Thanks Harold

[@randallcribb7015]

I have not been able to remove them without damage , i change the metering block to the other circuit with out main well tubes, if you look at the top of the metering blocks, main well if it has a cup type plug it wont have the idle tubes , if it is flat on top it has idle tubes , if you switch make sure it is from list#1850 and check orifice sizes, usual sizes of power valve restrictions are .046, idle fuel rest. is some where about .025 to .030 , emulsion holes usual about .027 . you will need some gauge pins to check sizes to be sure . ps I have never tried to remove jets and pry idle tubes up from the bottom of the main well , don't know if it will work . hope this helps randy

[@holleycarbshowtosadvice40y90]

Yes you can't remove them without damaging them, only way around this is to find you a metering block with out the tubes. I change them out. You can get an idea of sealing surface flatness with a short straight metal ruler, you have to cut to length. Has to fit inside the out edge. Hope this helps.

[@yazming1720]

Hi Randy first of all thumbs up on all ur videos very informative & easy to comprehend. I would like to ask if you could make a video on Holley 600cfm model#1850 on how to install a Holley Electric Choke. I've installed it on my carb but it binds & can't figure out where its binding or why. It will GREATLY be appreciated. Thanks Yazmin Venice Beach, CA

[@holleycarbshowtosadvice40y90]

Do you have a gasket between the choke cap and the housing?

[@joebassett4939]

Hello, I have a very old 4150 with a governor for a big truck engine 534. I believe it has idle restrictions under the idle well plugs. Do you think I can relocate like you did in the video? Thanks for your time

[@holleycarbshowtosadvice40y90]

Man you bring back old memories for me , I can't tell you how many old 477 and 534 engines with the Holley carburetors that I had rebuilt with the governor's built into them. If it has the idle plug with the idle tube all one piece it is hard to get the plug out of the metering block without damaging it, I tried but had know luck, it's possible to do , but I don't think it's worth your time and effort , man that was a long time a go, those where the good old days., One thing I can tell you about those motors , they had to have the timing right , I made the mistake of checking the.ignition timing with out disconnecting the vacuum advance hose , and the mechanical advance was frozen up , later the customer said his exhaust manifolds where glowing orange, all that was wrong was the truck pulled heavy loads so, under a heavy load the vacuum was down to almost nothing so the vacuum advance was not advancing the timing under a constant load , and the mechanical advance was frozen , so all it was seeing was initial timing , that's what made the exhaust glow hot ,I repaired the distributor and never for got that.

[@butchking154]

hi randy have been waching your vides for a long time , got a question , do i need to change out the ifr bleed on the sec side of a 4 corner idle also already done the front thabks butch

[@holleycarbshowtosadvice40y90]

Normally I don't but with some four corner idle circuits you may have too, l like to change out my idle air bleeds to a larger size after my transfer slots are set correct, then if I'm still to rich I will lean the ifr, just don't go to lean. Hope this helps.

[@butchking154]

@@holleycarbshowtosadvice40y90 thank u my friend hope to hear more vidios from ya take care butch

[@victoroneill4381]

Hi im running 2 x650 double pumper quick fuel drag/street carbs on a 671 blower.Now its running extremelly rich at idle 11.0 -11.7 (eye watering stuff lol ) and also rich at cruise 11.2 -11.6 on the AFR gauge and screwing in the mixture screws does not make much if any change at idle.Im looking to maybe drill into butterflys as you showed but have a couple of questions.Will increasing the idle air bleeds have the same effect as drilling holes into the butterflys?Why drill holes into all 4 butterflys why not just the primarys? when tuning the x4 mixture screws starting 1.5 turns out setting to the highest vacuum reading by 1 mixture screw do i then adjust all other mixture screws to wat the same setting is as the first one is set at? or do i adjust the others one at a time as i did with the first? Does adjusting the mixture screws have any influence at cruise and full throttle? I have reduced primary jets 3 sizers down is better and this also did help slightly lean the idle and cruise but still too rich at idle and cruise. solid cam 5.85 lift.vacuum at idle is 7-8 yes low but no vacuum leaks. any help and ideas i can try would be greatly appreciated thankyou.ps like your vids very helpful informative cheers from Newzealand

[@paintkaine]

Victor Oneill I have almost this same issues. I was wondering if you ever sorted it out. Thanks

[@victoroneill4381]

@@paintkaine Hey Aron sorry late reply havnt spent much time on the car much since last.though i did find 2 spark plug leads slightly burnt and timing was out a little which once i sorted those issues it brought up afr readings slightly but still little rich.I will prob still drill the primary throttle blades when i get more time though cant see why this wont work. cheers

[@holleycarbshowtosadvice40y90]

Yes there is a difference between bypassing air and idle air bleeds ,first check and see if your in the transfer slot to far, being it's two 4 barrels keep the transfer slot very small maybe .015 to .020 maybe smaller , drill bypass holes if needed, then change your idle air bleeds if needed to a larger size you may have to increase air bleeds alot , also you can just drill the primaries butterflies , I like to drill both if it's a four corner idle circuit but that's up to you , should work either way, go slow with all your changes, start with maybe one turn out on mixture screws , and go from there .I don't know if yours is a four corner idle circuit , if so keep your transfer slots small, if you by any chance have a air bypass built in under your air cleaner stud you might not have to drill your butterflies .I know this gets confusing hope I can do a video soon.

[@victoroneill4381]

@@holleycarbshowtosadvice40y90 Hi yes its a 4 corner idle circuit.i have been bust with other stuff but yes im thinking def drill the primaries and go from there.thanks for your help.cheers

[@joeyharris8268]

So you have to drill the idle restrictors yourself? Cant get em in different orifices already?

[@donrutter6765]

Joey Harris I cant find them, he said he can though.

[@holleycarbshowtosadvice40y90]

If your carb has screw in bleeds you can change them out, if yours has press in tubes be careful not to drill them to big because you can't go back.

[@cuzz63]

I dont have gauge pins but found that I can often use a drill bit and then use my calipers to measure the bit.

[@holleycarbshowtosadvice40y90]

Absolutely.

[@bertramlrezenet9311]

Hello gentlemen, sorry for butting in. A set of numbered drill bits comes in handy in this case, as the number on the bit specifyes a diameter.

[@Cuzntime]

So if the IAB's and IFR's do the same thing (make the idle circuit richer or leaner), how do you know which one to change first if you have a rich condition?

[@donrutter6765]

Cuzntime --- IAB's make a far less difference in A/f ratio change, try the other first. You dont have to change IAB's unless you have a dyno to see a difference.

[@Cuzntime]

I have a tunnel ram with 2 brand new Quickfuel SL600's (4160 style) and my idle mixture screws are all the way in (bottomed out) and its still a little rich (I have a big cam .270 @ .050).. The transfer slot is not over exposed and the PV is not blown.. I have the secondaries cracked open a little too.. The carbs came with .031 IFR's and just ordered some .028, hopefully that will help.

[@holleycarbshowtosadvice40y90]

That don't do the same thing , one controls fuel to the idle the other is the idle air bleed , transfer slots are fixed first then then take the guitar wire out and and adjust with your ldle air bleed if its still rich go bigger .

[@Blakep7704]

If you get the idle restrictor jet to large can the idle air bleeds be replaced with larger ones? If so what effect will this have over all?

[@holleycarbshowtosadvice40y90]

Making the idle air bleeds larger will lean the idle circuit, as long the transfer slots are correct and the idle fuel restrictor is not to large, every thing has to be balanced.

[@hilide]

So if I want to lean out my idle circuit, why couldn’t I increase my idle air bleeds sizes? Wouldn’t that have the same effect as decreasing the idle fuel restrictors? What effect if any on the transfer circuit if I increase idle bleeds or decrease idle fuel restrictors? Is it better to decrease idle fuel restrictors and leave the idle bleeds alone to lean idle mixture. My carb has removable air bleeds and IFR Thanks

[@holleycarbshowtosadvice40y90]

As long as the idle fuel restrictors aren't to large , you should be able to increase the idle air bleeds , and lean the mixture.

[@wakullabrocno32427]

Have you converted metering blocks to e85?

[@holleycarbshowtosadvice40y90]

I have converted to alcohol but you are much better off buying a block designed for alcohol. Hope this helps

[@mickangio16]

Hi, Randy. Your Holley carburetor videos are great but I think you should re-do this one without the confusion between the idle feed restriction and the idle air bleed. It doesn't seem like anyone realises how important the idle feed restriction calibration is for not only having a good solid idle but best drivability, throttle response, fuel mileage, and even emissions. In my opinion it's the most important modification you can do to tailor your Holley carb to your particular motor (and your own) requirements. Also, as respecting subscriber I would like to ask why does your channel only show 2 old videos? I think I've seen them all but if I want to watch one I have to look for it insead of just going to your channel for playlist. Looking forward to more. Keep swinging that screwdriver (carefully- it could hurt someone!) Thanks.

[@holleycarbshowtosadvice40y90]

I looked at it , I think you right.

[@jesslackey1003]

Questions if you have three emotion holes instead of two do you get better throttle response

[@holleycarbshowtosadvice40y90]

Jess i pefer the three hole, alot of aftermarket blocks will have up to five emulsion holes, but if you look closely most blocks only use three holes and block two. But I'm not saying you can't use more , usually three is enough, I can't say for sure about throttle response but I believe a fine tuned carburetor with the right size throttle plates and a three circuit emolsion is the way to go. Hope this helps. Thanks for the question and thanks for watching.

[@jarmominkkinen9409]

Tanks grate tips four May center carb .Have sixpack mopar 440..I drill The aire bleed litell bigger.the idel are grate Have.13.8 fuel Air.Can adjusterbal The idel mixur skryv abaut 2 turns aut.(.Normal Temp).Tanks Again👍👍👋👏

[@holleycarbshowtosadvice40y90]

That's great.

[@holleycarbshowtosadvice40y90]

Your welcome.

[@hippiemiller]

👍

[@holleycarbshowtosadvice40y90]

Thanks

[@skyper57]

Hi MATE why cart i just drill out the air bleed to make this circuit learner ...just asking

[@holleycarbshowtosadvice40y90]

You can but with if you want it right do transfer slots first. Hope this helps

[@Dodgechallengersixpack]

So this is recommended if you cant get idle adjusted after drilling throttle blades?

[@holleycarbshowtosadvice40y90]

Explain to me where your at , and describe your problem , and I will try to help.

[@Dodgechallengersixpack]

Just planning ahead. Not sure how the 6 pack will idle with new cam going in.

[@bgbalmes]

Hi Randy, I have a 4412 that I am try to richen up the idle circuit. I have the mixture screws almost all the way out and she is still lean. It has brass plugs at the top of the top of the idle circuit.0.40 is the size. What do you recommend me drill it out to make it richer. 0.43?

[@holleycarbshowtosadvice40y90]

If your talking about the idle fuel restrictor .040 is plenty big enough, I'm guessing your idle circuit is blocked or restricted or you have a vacuum leak, you can drill your ifr out to. 043 but i don't think it'll help. Hope this helps.

[@StandAloneAdventures]

Does this affect your fuel curve or just for leaning out the idle circuit?

[@holleycarbshowtosadvice40y90]

It has a an effect on the idle which is part of your fuel curve but not as much as the high speed bleeds.

[@73sebrougham]

Hey buddy , I have a question . I just bought a holley ultra 950 xp carb on my 440 , solid lifter .557 cam aluminum edelbrock heads 451ci , with 11.1 compression . My airfuel ratio is very lean at idle , it's pig rich at cruise and it's perfect at wot , 12.0 air fuel . It's really rich at cruise and it's stalling at idle and won't run unless I hold the gas . All settings are stock out of the box , except for a 3.5 power valve and .035 tube type squirters . How can I lean my cruise speed out ?

[@holleycarbshowtosadvice40y90]

I'm going to need some more information can you tell me things like stall converter, cam intake center line and duration at .050 also how far are your idle mixture screws are turned out, and engine vacuum at idle and in gear if its an automatic trans, also is your vacuum above 3.5 inches of vacuum at cruise. to lean out your cruise is usually done with the main jet , you can lean it some with your high speed air bleeds there is other ways to get correct mixture, one good thing about the holley ultra , it is very adjustable also shoot me the list number and I will help you get it right, also let me know how your distributor is set up [ advance locked out ] or how much base timing are you running, sorry so many questions, randy

[@randallcribb7015]

check engine vacuum make sure power valve is closed at cruise , if the power valve is open at cruise it will be very rich , if idle is lean you can change idle fuel restrictor to a larger size or put a smaller idle air orifice if they are replaceable , make sure you have enough torque converter stall or it wont idle. hope this helps randy

[@Moparmaga-1]

Hi, can I gain power by changing to a 1.75 throttle base plate, from the 1.563 ? I'm looking to make my classic hp 830 (80509) a little more suitable for my 471 big block mopar street strip car,

[@holleycarbshowtosadvice40y90]

If you have an 830 Holley your throttle plates should be 1.687 and I have made this modification but it's not a simple mod , does help throttle response , works better on the 750 Holley main body, we are trying to get the parts together for this video , please don't try this with out a video.

[@frankrizzo3922]

I have a question about a Double Pumper that has been gone threw but wont idle at all? Revs fine just no slow speeds.. float adjustment good, cant find any vacuum leaks ethier... I'm stumped..

[@holleycarbshowtosadvice40y90]

Check main body to throttle plate gasket, the wrong gasket will close off the idle circuit , this is most likely the problem.

[@frankrizzo3922]

@@holleycarbshowtosadvice40y90 yea the kit came with many different base gaskets... i had to guess which one... i bet your right, i guessed wrong... thankyou for the info.. 😁

[@butchking154]

hi randy , do we need to change jets up or down after this mod on the front metering block thanks buddy

[@holleycarbshowtosadvice40y90]

You should not have to make a main jet change after this mod, this is just a better way for the idle air and fuel to emulsify. When moving the idle fuel restrictor to the top of the metering block. 035 is the proper idle fuel restrictor size to start with . Thank you for watching.

[@butchking154]

@@holleycarbshowtosadvice40y90 sounds good buddy thanks for the reply

[@swatson0061]

Would you do this on both metering blocks on a double pumper? Or just the ones with a 4 corner idle circuit?

[@holleycarbshowtosadvice40y90]

Yes I do it to the primary block and if I'm changing to a 4 corner idle circuit, I will modify the secondary too. That video I made a mistake on the size of the screw in fuel restrictor it should be .035.

[@swatson0061]

@@holleycarbshowtosadvice40y90 thanks alot. I have a 350 that is burning everyones eyes at idle. Lol

[@holleycarbshowtosadvice40y90]

Alot of times you have to go to a bigger size of idle air bleeds to correct that richness that burns your eyes. Hope this helps.

[@swatson0061]

@@holleycarbshowtosadvice40y90 so would you try to restrict the idle circuit first? Or air bleeds?

[@holleycarbshowtosadvice40y90]

Larger air bleeds first, then smaller idle fuel restrictors if needed. Hope this helps.

[@jamest4363]

Is this why my 950 holley puts too much fuel to my engine?

[@holleycarbshowtosadvice40y90]

Absolutely could be

[@johna7184]

I have a 4781-5 that is fouling plugs at idle with a 270'ish cam at .050. My timing is locked at 42 degrees. This is a new engine and the car has only been driven once. I mainly idle it in the driveway. The transfer slot primary side is less then .040 and the secondary throttle position is 1/4 turn increase over factory preset. I have strong sensitivity on all four air bleed adjustment. Can I still be running rich even though my idle mixture screws are operating as they should? It sounds like what you are saying is that the fuel restrictor mod is only needed to gain functionality of the mixture screws?

[@holleycarbshowtosadvice40y90]

John always start out with your transfer slots and then work with your idle air bleed , then I will work with the idle fuel restrictor, but you have to remember with a cam that big you need alot of compression and a good strong ignition system. Try going through the idle circuit first and if that doesn't help let me know. Also does your carb have an adjustable air bypass? If not you can drill holes in butterflies and close your transfer slots even more , the more cam you have the less transfer slot you won't exposed , that way you have more control over your idle mixture.hope this helps.

[@johna7184]

@@holleycarbshowtosadvice40y90 Hey thanks for the reply much appreciated. No I don't have an adjustable air bypass. I'll have to drill the holes. The engine is a 489 BBC cam duration is 259/267 @ 50, I have an MSD digital six plus with mostly new components, but I need to check my secondary output. I'm not sure how.

[@holleycarbshowtosadvice40y90]

John sounds like you have a good combination , hope this helps.

[@philb386]

Hi Randy I have watched these 2 vids multiple times before I started drilling the holes in the butterflys. Instant success ! I had been at my wits end trying to lean off the idle, these vids were the best explanation I could find. So I have solved one problem but created another now, I have a lean stumble off idle, not accelerator pump fault, that works fine this is a lean spot as you are at minimal throttle for instance like when you just want to creep the car along it will stall. If you blip the pedal it will move fine. Is this a lean transfer slot problem do you think. It didnt do this when is was running a rich idle. The carb is a 670 Brawler vac secondary. 4 corner idle. 6 months old. Kind regd's Phil. NZ

[@holleycarbshowtosadvice40y90]

I need your ifr size. Make sure the float level is correct up to the sight hole this is critical and accelerator pump has no play at idle after drilling bypass holes. Sounds like the ifr circuit may be lean. Make sure ignition timing is set correct . Let me know. Hope this helps.

[@williamrivera4878]

I have a holley and the car runs good only issue is it won't pass 6500 RPM it's a Mazda rx7 and it should run about 10000 RPM do have any recommendations I've seen high RPM plates any help will greatly appreciated thanks I've also tried changing the jets all sizes

[@holleycarbshowtosadvice40y90]

William I know very little about rotary engines, sorry.

[@therocketshopper]

What changes usually need to be done to a 750 holley HP DP to use it on a 2x4 application on a tunnel ram?

[@donrutter6765]

brian taylor Smaller carbs.

[@holleycarbshowtosadvice40y90]

It matters how much cubic inches you have sometimes more accelerator shot and some less idle fuel but there is a lot of information I would need to get you close.

[@bobsuruncle7717]

I wish i new hàlf as much as you forgot👏.

[@holleycarbshowtosadvice40y90]

Let me know if I can help.

[@kerrygatling663]

Not sure if this was asked before, but is there a visual way to look at a metering block to determine if it's a 3 or 4 circuit block?

[@holleycarbshowtosadvice40y90]

Look on the main body side of thr metering block, right above the idle circuit. Hope this helps.

[@kerrygatling663]

@@holleycarbshowtosadvice40y90 What should i be looking for?

[@holleycarbshowtosadvice40y90]

An extra hole above the idle circuit is your intermediate circuit.

[@kerrygatling663]

@@holleycarbshowtosadvice40y90 ok Thx u👍

[@kerrygatling663]

@@holleycarbshowtosadvice40y90 Thx you👍

[@JoeyGarcia]

So what happens when you have 4 corner idle? Does that means you have to do the idle feed restriction mod to both the front and rear metering blocks?

[@powers6963]

yes

[@JoeyGarcia]

Thanks for getting back to me. I tried this modification. I measured the piece of wire to be about .018" and it didn't make too much of a difference. I don't know if I should either 1) try a bigger wire, b) drill the idle air bleeds, c) swap the main body for a retro fit so I can have screw in bleeds, d) install an transition slot restrictor, or e) all of the above.

[@powers6963]

Make sure you're transition slots aren't open too much. Get them squared up and make sure the floats/pressure are where they should be. Also, make sure you've got plenty of initial timing. I wouldn't mess with the air bleeds until you figure out the IFR size needed. Air bleeds are more for timing and fine tuning of the idle circuit AFR. If you're idle mixture screws won't kill the engine, something's off (probably transition slots too exposed). Hope this helps.

[@holleycarbshowtosadvice40y90]

Joey i guess your rich at idle , first check your transfere slots to see if there to far open if so refere to my other video and mods .

[@donrutter6765]

Transfer slots open too much will make the motor idle on the mains circuit and not the idle circuit. It will always idle rich. Start drilling your front butterflies at 1/16 drill bit. If its not enough, drill the back butterflies 1/16. Go to 1/8 on the front next and so on. But you start setting your idle on the REAR butterfly adjustment, not your front idle screw.

[@MattsRageFitGarage]

I took a couple of my spare Holley carbs apart today that were sitting on the shelf to examine the metering blocks and noticed that both carbs (4548 and 80457) have no pressed in IFR jet in either location. They are wide open holes all the way. The 4548 is from 1973 and the 80457 is from 1995. Would these metering blocks have some sort of predetermined orifice size cast inside of the circuit well where I can't see them? I ran both carbs on the same vehicle and they both acted totally normal with normal AFR readings. I did notice both metering blocks are using 4 well plugs on top of the metering block and I noticed some only seem to use 2 well plugs? is that why?

[@holleycarbshowtosadvice40y90]

Some holleys have an internal idle circuit in the idle well and some don't, look carefully at the top of your metering block the two outer wells sometimes have a flat plugs with an idle tube made into it, the inner wells will have press in cup plugs, but trying to remove the idle tubes out of the block will usually ruin the idle tube. Hope this helps.

[@MattsRageFitGarage]

@@holleycarbshowtosadvice40y90 The 4548 carb has cup plugs on the outer wells and flat plugs on the inner wells. The 80457 has cup plugs in all 4 holes.

[@holleycarbshowtosadvice40y90]

Some of the older holleys didn't have restrictors , most did. Some had the internal idle circuit , and i told you wrong the idle tubes were in the inner wells my bad, I would not try to take them out. If you use the non restricted idle circuit make sure you keep the transfer slots tight as possible, then most of your idle mixture will be controlled at your mixture screws.hope this helps.

[@timgroleau1612]

Still a great video

[@holleycarbshowtosadvice40y90]

Thanks again

[@garageforcerestos]

impressive knowledge Randy, do you help people one-on-one?

[@holleycarbshowtosadvice40y90]

If I can help you just let me know, you can leave a comment or we can talk by phone.

[@butchking154]

randy were did u get your 6/32 plugs at

[@holleycarbshowtosadvice40y90]

Bought em from a fastener company thats no longer in business, I also need to find a supplier. I'll look too, let you know butch if I find some.

[@butchking154]

@@holleycarbshowtosadvice40y90 k thanks buddy

[@holleycarbshowtosadvice40y90]

butch i found these plugs at aft fastners there called 6/32 by 1/8 socket set cup plugs. I believe these are the ones They have 100 cups for under 4 dollars. Take it easy bud. The all brass ones are more expensive.

[@butchking154]

@@holleycarbshowtosadvice40y90 hey thanks randy u are a godsend thank u for letting me know, i also found some at ruaral king farm store the name of the company is midwest fastner corp out of michigan thanks happy holiday my friend

[@holleycarbshowtosadvice40y90]

Thanks and take care brother.

[@dustinandersen1405]

Smokey yunic playing in the grey area of innovation. Cheating for those stuck in the box thinkers

[@holleycarbshowtosadvice40y90]

Thanks.

[@emmeygramzmoomar0304]

Hi randy ur always on point I love it brother... How can i possibly talk with you about a problem i have thats been causing us soooo much problem s

[@holleycarbshowtosadvice40y90]

Sorry it took so long , email me your number at [e-mail])

[@bgh70]

6-32 is a six-thirty two tap, not six thirty seconds. It's a number 6 screw with 32 threads per inch. 6-32, not 6/32. Your black plugs are just 6-32 set screws, which are very easy to find.

[@holleycarbshowtosadvice40y90]

I'm fine with that.

[@oscarantonionagaya7556]

Hola es posible un carburador 850 cfm trabajé como 650 cfm por motivo que el motor 350 es muy pequeño para ese carburador, saludos

[@holleycarbshowtosadvice40y90]

English only

[@oscarantonionagaya7556]

@@holleycarbshowtosadvice40y90 no problem,saludos desde Tuxtla Gutiérrez, Chiapas

[@oscarantonionagaya7556]

@@holleycarbshowtosadvice40y90 no problem , un saludo seguiré viendo tus videos con el traductor

[@michaellopez550]

What's the deal with a 850 base plate on a 750 body

[@holleycarbshowtosadvice40y90]

It's a good up grade , for a 750 double Pumper, I will try to do a video soon.

[@nepoleonbonaparte6517]

Got one at the moment that won't idle a pro systems 4 corner idle carb has the passages front to back epoxeyed up to isolate the mixture crews I can't get it to idle at all dead cold it is fine after a minute ot two it's won't idle at all.up down up down ..cover the carb with your hands it idles must have a Crack in the main body that I can't find .everything is square no wwrpage..am I missing something in the metering blocks. ..I have done many been racing holleys for 4 decades this one is stumping me .any advice will be appreciated

[@holleycarbshowtosadvice40y90]

If you epoxy to far up the idle track you will block the idle mixture hole at the end of the track, not the transfer slot but the idle mixture holes. I usually only epoxy about an inch or two of the track at the most. if this is it just get the right size drill bit and measure another plate to get the proper depth of the hole , gently drill the epoxy out carefully not to go to deep and check the small idle hole that leads to the bottom of the throttle plate just below the butterfles to make sure there open.hope this helps.

[@nepoleonbonaparte6517]

@@holleycarbshowtosadvice40y90 thanks much I will check it out today thank you thank you !!

[@nepoleonbonaparte6517]

Do you think I should just replace the base plate with new AED base plate?

[@Baker504]

Good video👍🏻

[@holleycarbshowtosadvice40y90]

Thankd.

[@ronsmith7739]

In my opinion, Holley's are not a very good carburetor, it is a good high performance carb, but not for gas mileage. Carter, especially the AVS, and the Rochester Quadrajet carburetor are very good gas mileage. The reason is the vacuum secondary's in the four barrel carburetor, they are easy adjustable and Holley's are not. the main reason on Holley's are "double pumper's and not for gas mileage. The power valve, which is simply an open and close, not variable and that's it.

[@holleycarbshowtosadvice40y90]

I think holley's are a great carb and not just for high performance use ,but for fuel mileage I do like metering rod style carbs too.