How to Set Idle Mixture Screws

[@stevefickler1994]

I've adjusted 1000s (Yeah THOUSANDS) of carbs in 25 years of doing Emissions Testing at my business. Check the freaking vacuum hose hook ups before you do anything. Like he says, CHECK IGNITION SYSTEM FIRST. I also drag races cars for 40 years. This guy knows his stuff, too.

[@19amw87]

I'm getting ready to have the engine rebuilt in my c30 and have been binge watching your videos the last couple days, it's pushed me towards getting a properly sized avs2 instead of fighting my 800cfm performer, and take the time to fully tune it instead of just setting the idle circuit and choke. I appreciate all the work you've put in and just wanted to share some past tuning experience, the way i was taught as a teen I was taught by an old timer to set the idle circuit like this: (Starting with a warm engine) Set both idle air screws 1.5-2 turns out, back the throttle screw out until the throttle plates are fully closed, open 1 idke air screw until rpm stops climbing and note position, close that screw until rpm stops dropping and note the position, turn that idle air screw open about 3/4 of the way to max rpm. Repeat with the 2nd idle air screw. Double check the 1st idle air screw. Double check the 2nd idle air screw. Set the throttle screw just high enough for a smooth idle (on manual transmission trucks), for automatic set the parking brake (and block the tires), put it in gear, and set the idle just high enough to be smooth (preferably with someone in the cab holding the brake pedal). On all the stock 350 truck engines I've had this ends up being 800-850 rpm when checked with a tach. For beat up old work trucks it was "good enough" but using the vacuum gauge would definitely make for a more precise tune. Prior to having anything more than the most basic timing gun we always set the advance to 10 degrees on the timing marker on the timing cover (with the distributor vacuum advance disconnected), it wasn't until several years later I found out those tabs are rarely accurate and most of ours were only running 6-8 degrees advanced in reality

[@kirklarson116]

Welp, this vid completely explained a problem that has been confusing me for years. I have one of these edelbrocks on my lightly built 283 thats in my 56 chevy truck. Slightly bigger cam, intake, headers and distributor and a bunch of chrome dress-up stuff. I couldn't figure out why I had to run my idle mixture screws all the way shut...it made no sense to me. It ran "just ok" but I could tell it was rich, I started playing with the metering rods and jets and got it the best I could. Well, today is carb rebuild day because the accelerator pump was leaking. Got it cleaned up and started back together but had to come in the house to get my glasses so I could read the jets and figured I'd have a beverage and watch a tuning video. I'm glad I did...you gave me some great information!!!

[@MuscleCarSolutions]

Good! If you have any questions, don’t hesitate to let me know. Always happy to help.

[@kirklarson116]

@@MuscleCarSolutions ​Thanks for the offer to help...not sure if I need help but maybe. First off, I have a 283 that came out of a 57 Chevy truck and since 1996 has resided in my 56 Chevy 3100. I had the machine shop do whatever they needed to machine just to clean it up for a stock rebuild. I wanted a little bit of a cam for a little bit of that sound. Have headers and an Edelbrock manifold from the late 90's. Got the rebuilt carb on today and went through the process of setting idle mixture and idle speed. It's idling good now and responds instantly to WOT. I have it idling at 780-790 and at that idle it's at 9.5" Hg. Now for the weirdness. I get tach and MP responses when I mess with the drivers side idle mixture but I can close the passenger side all the way and there's little difference in idle. My manifold is a square bore but it has a divider that separates the left and right side of the carb. This divider isn't sealed by a gasket...is this a problem? I am certain all ports and passages are clear. It's running good but I'm not sure it's running right. I've seen spacer/adapter plates that are installed between the carb and manifold...is this something I need? I'm a competent mechanic...just not totally competent in tuning with performance stuff. I look forward to reading your thoughts, Thanks, Kirk

[@Gary-Anglebrandt]

Same here. I get response from the Edelbrock, but it's minimal. Makes me curious about my old Quadrajet, too. I replaced it with an Edelbrock when the idle mixture screws didn't do anything. I thought the bore holes were wore out, but maybe it was the same thing as what he describes here. I still have it, so maybe one day I'll give it another try. Great stuff here. Can't wait to try this the right way now.

[@clean1566]

You know you’re making a good video, when it makes you want to go tune your carb, right

[@bradsheap6474]

I just got me a new truck with a carbureted 5.7 350 and it’s idle is a little rough. I was thinking I needed to play with some screws but thanks to you I now realize I need to double check my fuel pumps and spark plug and even my air filter before I even consider messing with the carb. Thank you!

[@MuscleCarSolutions]

Timing!

[@bradsheap6474]

@@MuscleCarSolutions ya I’m hoping it’s not timing or imma have to recruit my uncle to help me out with that lol

[@MuscleCarSolutions]

@@bradsheap6474 timing and carb tuning are done together.

[@felkerforcongress]

I really do appreciate your video... I have an edelbrock 4 barrel carburetor and had it adjusted on my 1986 monte ss, and when it gets hot outside and the engine warmed up, the car chokes itself and sputters when you hit the throttle hard. My mechanic adjusted last fall before I stored it for the winter and noted he adjusted it on the lean side. This showed exactly what i needed to adjust. Think I was running a little too lean. I ended up making slight 1/4 adjustments counter clock wise to both screws, and that so far seemed to take away that stalling away when I get into the throttle. Very informative and easy to understand.

[@MuscleCarSolutions]

Idle mixture screws aren’t in play past 1000 rpm. Keep the name in mind. IDLE. What you’re describing gets into the actual tuning of the carb. I’d verify the float level. This is where having a pressure regulator becomes critically important. Dial it in at 6 psi and adjust down from there. Make sure you have a spacer between the carb and intake to block the heat transfer. This time of year in hot climates need that spacer to block the transfer of the heat from the engine to the carb.

[@felkerforcongress]

I finally purchased a 3/4" Spacer from Edelbrock and it took care of my issues completely. No more stalling after car is up to temp, and starts with ease after its up to temp. Thanks again for the great info MCS!

[@GarrettGaina]

I've watched this and your dual quad video recently and I feel like I've learned so much. I've been helping my dad wrench on his 1962 Chevy Impala after many years of sitting. He's had the car longer than I've been alive and I'm happy to finally be able to work on it with him after being generally useless when I was a kid, lol. It's a dual quad 409 with 650 cfm edelbrock's. It's bored .030 over from a previous rebuild, has lower compression pistons, and my dad said it has a bigger cam than stock. I got it timed better earlier this year, about 35 degrees total mechanical advance, but I don't remember the initial timing. I had the idle mixture screws set for around 1.5 turns, but we can't get it to idle below 1400-1500rpm. I've got it in my dads head to put a fuel pressure regulator in the system and to pick up a vacuum gauge so we can get accurate readings. He was just happy to get it running better than it was this year and wasn't interested in pulling the carbs to see if we were engaging the transfer slots or making any other heavier adjustments. I know there are a lot of unknown variables in this rambling paragraph, but do you have any tips for helping a dual quad 409 idle happier?

[@MuscleCarSolutions]

I think you’re on the right track in verifying the transfer slots aren’t exposed. Easy job to pop the carbs off to verify. Then you know your starting point with the carbs. Verify the fast idle cams aren’t engaged on either carb. What is your engine vacuum at idle? What step up springs do you have installed? 650s are w bit aggressive for a low compression engine so you’ll likely always fight a rich condition. Start with the above and see what you can discover.

[@GarrettGaina]

@@MuscleCarSolutions I don't have many answers for you. Unfortunately my dad has the car put away for the winter now as it cools down here in Michigan. I appreciate the response I hope to get on the right track in the spring.

[@MuscleCarSolutions]

@@GarrettGaina if you’re using ethanol added fuel, make sure you drain the carburetors and put an additive in the tank to keep it stabilized and as much of the moisture out. This is what I use for long term storage. amzn.to/3vyT29A

[@db3170]

Vacuum leak my guess

[@jeffschubert4715]

I enjoy watching and learning from you...needs to be more people like you...great job..always look forward to seeing new videos from you..

[@MuscleCarSolutions]

Wow! I really appreciate your kind words. I do it for fun and to hopefully help folks with their projects. Thank you!

[@vickikgibson9470]

This is such great information. You are the first one I found who actually shows how to use a vacuum gauge system to set it up! Now I will go get that so I can get a better set up on mine for my 85 Camaro I drive every day. One has to change things for winter vs summer driving!:) Thanks so much!!!:) Great job! Now all I have to do is figure out the throttle cable. My mechanic put a tie on it! Like whaaat!?? Now I have to replace or fix it better!

[@MuscleCarSolutions]

Glad it was useful! I try to be very through in these videos.

[@vickikgibson9470]

@@MuscleCarSolutions And that is really appreciated. People don't know that older cars will be needed, even if they are transferred over to other running systems. But being able to work on my own car over the years has sure helped me out. Living alone means you also have to be very self sufficient as possible. Information like this that is detailed, telling how, why and what to do MATTERS...A book can only say so much! Show and tell was always the best teaching method. So great job there buddy. I will recommend your videos and use this myself as I trim mine this spring:) I have one just like this! I learned to weld so I could rebuild my entire car. She is looking way better than me!LOL Cheers!

[@MuscleCarSolutions]

Something very satisfying about putting your hands on something and leaving it better than you found it! Thank you for the kind words. If you can weld, tuning a carburetor will be easy! 👍

[@Beekeeper_of_All_Trades]

fantastic tutorial. thank you for explaining how things interact with each other. Without knowing how carburetor components work with all the adjustment screws it would be impossible to properly tune

[@madformustangs-sl7br]

Very good advice, been in the trade 40 years, got taught way back when it was only carbs, same principal for every carb engine, not just 8cyls. I learnt to listen to the engine when setting up, but checking with a vacuum gauge is far more accurate.

[@MuscleCarSolutions]

@@madformustangs-sl7br I do a lot of tuning for folks who “did it by ear” and almost 100% of the time, its miles away from being good. The tools are available! Use them!

[@robbroberts2180]

Great Video with commentary that is understandable for guys like me. C3 with a SBC 350 Edelbrock. Many thanks !

[@MuscleCarSolutions]

Cool! I know these make for longer videos, but I want to cover all of the “why” when going through the process. Very glad you found it useful.

[@turnipsucks6416]

I'm a newbie at this, and the video is fantastic. Will be practical applicating this to my kids car soon. Thank you!

[@MuscleCarSolutions]

Glad it’s helped! Just let me know if you have any questions and I’ll do what I can to help.

[@turnipsucks6416]

@@MuscleCarSolutions Sounds great. Thank you.

[@BPattB]

Thank you great job just picked up a use Edelbrock 1406 and and the transfer slots were exposed all the way. The idle screw wasn't even touching anything, I backed off the fast idle screw and watched the transfer slots disappear. This is a great this is a great video for someone that's about to put a used a Edelbrock on their car!!

[@MuscleCarSolutions]

Glad it was helpful!

[@BPattB]

@@MuscleCarSolutionsyour videos are what KZbin used to be, and still should be. People with an area of expertise giving their opinion and help!

[@MuscleCarSolutions]

Very much appreciate your kind words. You’re the exact reason why I decided to make these videos. Couldn’t be happier it was useful for you. Thank you!

[@BPattB]

@@MuscleCarSolutions 👍

[@diesel1586]

I love this because I’m in the process of replacing the old Qjet with a 1406 on my ‘85 K10 and I’ve been referencing these videos over the weekend, yesterday was the rebuild and mounting phase, today will be running the fuel line, I bought the Edelbrock line with the banjo bolt which I’m not too crazy about but hopefully it’ll work out. That being said, it does give me a little extra confidence to be able look back at some of the videos, so thank you for that

[@MuscleCarSolutions]

That was the whole reason I started doing these Edelbrock carburetor videos! Glad they’ve been useful for you!!!

[@cutl00senc]

Now we need a video about setting initial ignition timing and what to do about vacuum advance. Great video!

[@MuscleCarSolutions]

It’s coming. Just waiting on an engine to get out of the machine shop. Hopefully in try next month or two. Thanks for watching!

[@AZHighlandHomestead]

@@MuscleCarSolutions have you made this initial ignition timing video yet?

[@nursecuenca]

On my edelbrock carburetor, vacuum manifold hose goes toward transmission. Is that port where I place vacuum gauge? I'm learning about cars from watching your videos.

[@cutl00senc]

@@nursecuenca vacuum gauge can be attached to any port on the manifold. I use the port on the carb in the front on the lowest level closest to the manifold. Should read high at idle and drop on rev ups.

[@ke6bnl]

I have an edlebrock carb on my 327. The issue I have is to start the truck I can not give it any throttle to start it, or it will crank a long time. What should I look into?

[@cbb_joker24dpmotorsports61]

By far 1000% this video has helped me the most I appreciate you going from top to bottom with this and all the in-betweens❤ thank you!!!

[@MuscleCarSolutions]

Nice! I’m glad it was useful! Thanks!

[@stiefbeen22]

I assumed the engine was rather new/fresh, but this explains it. Thanks for the video and your reply.

[@MuscleCarSolutions]

Its fresh now! That poor old small block was worn OUT! I’m surprised it ran as well as it did.

[@Jim-sr4sm]

Thanks for your help with the Carb adjustments!

[@EduardoPerezGandia-k8i]

A very instructive video. I have learned how to calibrate the carburetor for my Chevrolet Caprice 1966. Thank you very much.

[@MuscleCarSolutions]

@@EduardoPerezGandia-k8i glad it was useful!

[@bobbydelamar606]

Great video. I need to tune up my 1970 Roadrunner with the 383. It starts and idles but it's hard to get it there. The exhaust burns my eyes. I just got the car so don't know everything about it. Sounds like it has a bigger cam. It has a 4 barrel Edelbrock and the mixture screws don't seem to effect it. I have not put a vacuum gauge on it yet.

[@MuscleCarSolutions]

If the mixture screws have no effect, you’re into the transfer slots. Nothing you can do until you fix that and get the idle down. What’s you’re initial timing set at?

[@bobbydelamar606]

@@MuscleCarSolutions I dont remember, It's been awhile but timing I think is at 8. What's a good set point? I've been fixing a few things on this car from the previous owner. I found a rag wrapped around the oil pick up tube!! Probably when they messed with the cam.

[@bobbydelamar606]

@@MuscleCarSolutions I'll check the timing again. The vacuum advance wasn't hooked up to the distributor. I think I have it right now.

[@MuscleCarSolutions]

@@bobbydelamar606 8? Go 12-16 initial. Guess we need to start at the beginning. What’s your fuel pressure regulator set to? 4.5-6 is your best target range.

[@bobbydelamar606]

@@MuscleCarSolutions Okay I'll recheck timing again. If it's mechanical fuel pump, is it the same procedure for checking pressure?

[@ryankennedy9414]

Great video. I used your guidance today trying to sort out my 1406 on a 1980 Dodge 318. The truck was given to me so I don't know the cam, but initially I thought it had some lope, but after some tuning, maybe not. Has long tube headers, that's it. We had issues once warmed up, at a stop in gear the truck would start to lurch against my foot on the brake, to the point where it would eventually stall if I didn't shift into neutral. This only started when I had the transmission rebuilt, I assume as it no longer had the slip the old one did. I did the screws all the way in, then two turns out, and backed the idle down and it was much better. Vacuum over 19 all the time. It still has some issues though, which I was looking at your other video about tuning charts on. I personally thing the 600 is a little overkill for this engine, and I am guessing its running rich. It smells rich, and at any throttle off coast you hear small backfires within the exhaust. I am just ordering a timing gun with RPM so I can do this idle tune more correctly (going by feel right now) but this sure did help alot. I did notice, when screwing in and out to find the limits where it started to stumble, it definitely does way out, or nearly in, I found the range in between hard to choose. It seemed between those two point there was good two turn of screw adjustment that didn't alter the RPM or vacuum so I was a little stuck on where to leave it. I am looking for cruising, and thinking its running rich I went on the lean end. Thanks for the great video!

[@MuscleCarSolutions]

Yup, that’s entirely possible. It’s kind of on the edge of being too big. If you look at the video on how to select a CFM, you’ll see it’s probably close to one or the other. I think if you’re honest about the max rpm, it will probably point you at the 500 being a better size. But you’ve got the 600, might as well run through the tuning chart and see how good you can make it? Sometimes it’s tolerable once you get it dialed in. And for sure, there is always a point where no matter what you do, it doesn’t get better. That’s usually your time to lock her down and go have fun!

[@ryankennedy9414]

@@MuscleCarSolutions Thanks. I forgot to mention, while I had the Vacuum gauge on that port, the EGR valve had no vacuum and the engine seemed happy, but when I put the vacuum line back on the EGR the idle went more choppy. It seemed like the truck was much happier with no vacuum on the EGR. Any thoughts? I sorted adjusted around that so it was sounding happier when I put the vacuum line back on, as setting it perfectly without it meant it didn't run great when I put the line back on.

[@davidhaxton5050]

Great video for helping people like me who are not great at all this tuning stuff!

[@MuscleCarSolutions]

That was the entire reason why I started this channel in the first place. It’s not difficult. Just need an explanation and you’ll find out you’re capable of it! Thanks for the feedback. Much appreciated.

[@CarlosOro777]

Good helpful video! I have recently bought a new EB 1406 carb for my 79 Dodge RC 360 and was having issues getting it to start and idle correct, I took out the left Idle Mixture screw to inspect as you suggested and discovered the tip was broken (and got stuck inside) so I had to drill it out and got a new screw, but now when I tried to make the idle adjustment it won't reach highest vacuum as shown, it was in the red zone (at 15/ LATE IGNITION TIMING) how do I fix this!?

[@MuscleCarSolutions]

@@CarlosOro777 don’t know if there is a fix. If you drilled into the seat that screw meters fuel though, it’s going to be impossible to adjust. Vacuum isn’t a set number for all engines. Without knowing the cam profile it’s hard to guess what the vacuum might be. What’s you’re ignition timing set to?

[@1badombre82]

Super helpful! Will be doing this after I reset my timing this weekend. And I'm glad you told me to check the metering needs after. And as always I gotta make a joke. "Don't be that guy that's always playing with it" yeah yeah my girlfriends always saying that too 😅

[@MOPARMuscleLEBANON]

one of the best and easy videos i've ever watched , am having problems suddenly with my street demon 625 carb on a stock 400 big block mopar with MSD ready to run distributor and coil , running very rich no power going uphill , i put a 600 cfm edelbrock now for testing ran okay not bad ( sure it needs some tunning ) but weird thing is when am backing up my car on a slight hill to enter my garage it spits black smoke out of the exhaust and it hesitates what could be the problem

[@MuscleCarSolutions]

Start with the easy stuff. If it’s spitting out black smoke, it’s likely rich. So look at all the common things that would cause that condition. Needle and seat - obstructed or trash holding it open. Good time to view the rest of the inside. Any trash or debris, clean and new kit! Fuel pressure. I’d you’ve watched any of my videos you know I’m a huge proponent of running a pressure regulator - no matter what type of pump you’re using. Gives you another adjustment point, which could be used right here. And as always; timing. Carburetors and timing go hand in hand. So recheck your initial timing. If you’re down around sea level, I generally start at 12-14 BTDC. Floats are another. The street demon uses a nitrophyl floats but they can experience some changes depending on age and condition, as well as being set too high. Heat! If you’re north of the equator, you’re likely into warmer weather. If the carburetor is bolted directly to the intake, the longer it runs, the more heat it absorbs. The more heat, the more the ethanol added fuels hate it. I’ve done videos on all of these topics if you want to take a look at go more in depth.

[@stephencrisci2905]

What color springs n metering rods should be in carb for stock 5.7 dual exhuast...stock cam...😊thank you..good video helpfull...

[@MuscleCarSolutions]

There is no set answer. Make sure the carb is to the factory settings and start tuning. Springs depends on your engine vacuum.

[@Tk-ou9ec]

Older video I know but a quick question for you! I too am running an Edelbrock 500 on my mild 318. It was professionally tuned for me back in 2019 and has never given me grief at all,it just runs good. However,lately under very light throttle it will stumble a wee bit,nothing major,but noticeable. I do not own a vacuum gauge but I’m lead to believe that this represents a slight lean condition? Otherwise carby is fabulous. Your thoughts please.

[@7C_3D_PRINTING]

Thank you thank you thank you for these videos. My buddy has a 70’s nova 305 rebuilt for drag and strip. Has a Holly carb and a dui distributor. I’m gonna go and implement some of the stuff I’ve learned from your videos.

[@NickGreiner1988]

I've had the best luck tunings carbs by making sure the engine gets to full operating temp first, thst means taking it for like a 10 minute drive first then quickly parking up then setting the mixture screws. My car never gets quite as hot if i just leave it idling, plus the plugs start to foul up anyway. If i only idle it up to temp then set tge mixture i find that when i think I've done a good job and go for a drive, when i stop and the car is idling, it's usually richer than i had initially set it.

[@MuscleCarSolutions]

@@NickGreiner1988 yup. Always at operating temps. But even that’s a bit of a moving target.

[@brycedelaney4301]

I'm about to start my sbc for the first time with the distributor roughly set and the carb. I haven't ran this edelbrock before so I don't know what to expect. Any tips on how I should go about the first start of the engine with rough timing and carb?

[@deankay4434]

You have to begin cold to check choke operation, linkage to fast idle cam and adjust as needed to factory AFB settings. Check timing chain condition while rotating crank to TDC, backward while watching rotor. If 0-10, some wear, if 12-16 replace, if 15-16 or up, it can jump a tooth. If fresh paint, run compression test, cylinder leakage and adjust hydraulic lifters both roller and flat tapper at zero lash on push rod up only, not spin or rocker wiggle, then tighten 1 1/2 turn to place the plunger pistons in the lifters bore. Then place on 8-10 degrees BTDC on power stoke. With key on, engine off, "ST125" or other spark tester in wire #1, retard distributor and slowly advance until spark occurs. Tighten distributor and use timing light. It is just left of the die cast Tach-Dwell Meter in the tool box on top of the 7 distributor wrenches. Have a nice day. DK, ASE master tech since 78, retired.

[@AngelJMartinez-t5q]

This is a great video! not bad at all i am looking for symptoms on why the engine dies when idling or turning i have to put it on park and turn on again. Does it have to do with ignitions like spark plugs ?

[@MuscleCarSolutions]

Timing or fuel. Your challenge - figure out which! What RPM do you have your idle speed set for in drive?

[@joshuaatkins5197]

Great refresher! There's a reason I don't use multi-purpose screwdrivers with attachments on carbs though. It's hard to drop a hole screwdriver down the throttle blades but a screwdriver tip? Bye bye. Also thank you for not playing obnoxious music while you're trying to explain this.

[@MuscleCarSolutions]

It’s at idle. Throttle plates are closed. Zero worries.

[@joshuaatkins5197]

@@MuscleCarSolutions guess I was thinking they aren't always closed in every situation and dropping something down the carb is never a good situation 🤷‍♂️ so for people learning ( what this video seems to be aimed at) it might not be a good habit. Happy Sunday 🍻

[@dynamike7108]

If you put the vacuum gauge on the ported side to begin it will tell you if the transfer slots are closed. No vacuum means they’re closed. I usually screw the idle adjustment in to get max idle with no vacuum. Then I know I can always turn the idle down but not up

[@superdave103harley]

Still one of my favorite videos! Excellent brother

[@MuscleCarSolutions]

Thanks! Glad you liked it!

[@maaseace]

I have an problem on Elderbrook on my sons 1964 k20, when we parked it about a year ago it ran just fine. I put the fuel stabilizer in as well, went to go get it running for the summer, and it will not start. I purged the fuel line all the way up to the carburetor. I noticed when I loosened the line at the carburetor there was a lot of air pressure coming out. The air was purged out, I attempted to prime the carburetor. The engine runs just fine when I pour fuel into the carburetor but it doesn’t seem like I’m getting any fuel out of the carburetor jets. What should I look for when I get back to this thing?

[@MuscleCarSolutions]

Mechanical pump or pump in tank, doesn’t matter. Disconnect the line at the carb and crank the engine over or cycle on the pump and see if you’re getting fuel. If not, start at the carb and work back. Replace fuel filters. Disconnect and blow through the lines with compressed air to see if any garbage comes out. Lastly drop the tank, empty and clean. Once you have that sorted out, then remove the carburetor, clean,inspect and put a new kit in it.

[@alfredovegacortes777]

Hello Sir I have a question about a 4 barrel carburator on a 1985 winnebago itasca motor home it has the 7.2 engine on it that it doesn't pass the smog check as it seems the carburator is using too much gasoline, is there an adjustment to reduce the amount of gas the carburator uses ? thanks

[@MuscleCarSolutions]

Unsure what engine that is. Factory stuff is usually pretty simple. If there’s a problem, it’s not usually an adjustment. It’s determining where the problem is. Rebuild. Filters. Garbage in the carburetor.

[@blownzed]

You adjust your carb with vacuum advance hooked up? Doesn't the timing keep changing with the vacuum changes? And doesn't that affect the idle? Help me understand this because every other source says to block off the vacuum advance prior to adjusting the carb.

[@MuscleCarSolutions]

@@blownzed it wasn’t. I capped the line at the distributor

[@hvspeed6102]

Great video. One question I can’t seem to get answered. Doing all of what you’ve shown, I end up with over a half turn difference between sides, in order to get the best readings/ idle quality. Is that normal? Stock SBC 350, essentially same stuff you’re working with. Runs fine, just always hear the two screws should be adjusted the same number of turns. I just replaced my older Edelbrock 600 with a new AVS 650, both carbs were the same way, 1 1/2 turns on one side, 2 1/4 the other. Thanks.

[@gurtajdhillon23]

Hi there, wondering what your fuel pressure gauge + regulator+fittings you have connected to the fuel line elbow? Im really liking that setup, do you have/need a return line? Thank you

[@MuscleCarSolutions]

Mostly Russell fittings connected to an Edelbrock fuel line. No return line on this set up.

[@jennysmith3224]

I enjoyed your videos 👍 Is there a way to know if the transfer slots are exposed with carburetor already installed? 2nd question , Why is there two air fuel mixture adjustment screws. 3rd question The carburetor we have only has a vacuum tub going to left slot and right slot is closed off. Son insisted on buying 1984 Chevy s10, Small block, serial number is faded. Stripped down to just engine and carb. Help please

[@MuscleCarSolutions]

Well it’s a bit of a guess but one way to know almost for sure is if the idle speed is around 1000 rpm. Other than that, remove it and confirm and start the fix. Thanks for watching!

[@Brian-lu3tf]

What do you do when due to cam, ect, in order to get the idle where it needs to be(950 in my case), the idle speed screw has be far enough that the transfer slots are exposed? I know on Holley's I can set the secondaries cracked, and that helps with that, and in extreme cases in the past, drilled holes in the throttle blades...what about on the 1406 AVS? The overlap on the cam in this engine (350 chevy, prior owner installed a pretty hot cam, not sure what the specs are), and I am pulling a max of 12.5 inches of vacuum...Got the initial advance on the HEI at 14 degrees, total advance 38, all in by 2800...if I advance more the idle goes up, but so does the temp...so I cannnot really go much further...I have a vacuum advance that adds 10 degrees at idle as well, so with that hooked up, I am idling at 24degrees. I have heard everything from drill small holes in the plates like we used to on holleys, to adding a vacuum bleed to the PCV or Full Vacuum port(right now feeds the HVAC system)...right now, I turn the carb over after getting it idling as good as I can at 950, set the mixture screws best I can using vacuum guage, I get very little effect, and almost half the transfer slot is exposed under the blades...

[@db3170]

Digital tach a must adjust air/fuel mixture for maximum possible rpm then readjust idle screw then readjust mixture screws for maximum rpm then readjust idle screw again down ultimately closing the butterfly and creating high nozzle velocity and remember to fatten up for cooler temps

[@metropdmhatt]

Thanks so much! Does it matter what side of the carburetor to plug-in vacuum gauge? I get different readings, depending on which one. I may have a cracked header.

[@MuscleCarSolutions]

8:40 in the video tells exactly what port it goes to. Full manifold vacuum. If the gauge reads zero vacuum, there’s no reference point to adjust.

[@CompanyofWolfs]

Did my hiace 1994 cleaned it and then it stalled when starting up. Then adjusted the white screw on the side of the carburettor and the fuel idel now it seems to be okay but have to pump gas when cold starting otherwise doesnt always turn over. Also stalled downhill wich was odd whats wrong with it? Didnt used to do that

[@kend6875]

I have a question, you talk about making sure the transfer slots aren't exposed when you put the carb on. So looking at the carb with the base sitting up towards you should you be able to see the vertical slots at all before you put it on? At 6:33 you can see them and say they should be backed off quite a bit but you can see them. I ask because I am having a tough time getting my carb set up on my 72 C20. The 350 motor has had work done to it but I have no clue what, the person I bought it off of couldn't tell me anything. It sounds like it has a decent cam to it and has been bored 30 over (355 is all the guy could tell me that was done). It has an edelbrock 1407 on it and I put a edelbrock rebuild kit in it. I just can't get it to idle right and nothing seems to adjust it. I've watch all your video's a few times now and it seems like the transfer slots might be the root of all the issues.

[@MuscleCarSolutions]

What’s your initial timing set at?

[@kend6875]

@@MuscleCarSolutions I honestly don’t know I just went to check and my timing light isn’t working. As far as the transfer slots should you be able to see them when you’re looking at the bottom of the carb before you put it on?

[@MuscleCarSolutions]

@@kend6875 don’t ignore your timing. You can unscrew your idle speed screw all the way out and completely close the throttle blades. You can attempt to go through the process. But if you’re working on 5 degrees of initial timing, or your fuel system isn’t set up properly, it doesn’t matter what you do. You’ve GOT to get your TIMING and FUEL SYSTEM set properly FIRST. Sorry your light isn’t working. Go borrow one. Rent one at your local AP store. Buy a new one. Whatever you need to do, but nothing you do on a carburetor matters unless timing and fuel are right.

[@kend6875]

@@MuscleCarSolutions Thank you for the response! I’ll have to go buy a new timing light tomorrow and get one with a tach. And after watching your other videos I’ll have to get a fuel pressure regulator and get that in my fuel system. And get a vacuum gage. You’re videos are super informative! Not many people truly know how to work on carbs and I definitely don’t. It’s a big learning curve and I appreciate the help

[@MuscleCarSolutions]

@@kend6875 it’s a process. Sometimes that process is difficult. The details matter! When you get those details right and you start to see progress, then it all starts to make sense. Trust that process!

[@ragstarr]

hello! why would you run the distrub on the port vaccum? dont you wont more ignition on low rew/mixture? moste engines will overheat if the ignition is set to low (port vaccum)? sorry for bad english...

[@MuscleCarSolutions]

Anyone that tells you an engine can only run its vacuum assisted advance at full manifold isn’t educated enough on the topic. There’s a reason for both. Most of the street cars I tune are on ported vacuum. Once you get into the more aggressive cam profiles, manifold might be the better choice. The fact is there is no right answer. You tune both to see which is best for the application. If there was no reason for ported, the aftermarket carburetor companies would have removed it decades ago.

[@ronwatts268]

My vaccuum gauge isn't a steady reading it drops some then goes back to where it was. But it does change when turning the screws. Idle set at around 1000. 289 hipo 1405 carb

[@MuscleCarSolutions]

@@ronwatts268 need to know a bit more about the set up. Cam profile, intake, CR, transmission type and stall of it’s an auto, and where your vacuum leak is located. 😉

[@ronwatts268]

​@MuscleCarSolutions it's my father in-laws Mustang (k code) manual. I'm pretty sure it's stock considering what type it is. It has a Weiand intake. I'm not aware of a vaccuum leak.

[@MuscleCarSolutions]

@@ronwatts268 so stock cam, stock compression ratio? That takes us down a different rabbit hole on the carburetor being too big, but first I’d lock down why it won’t idle under 1000 rpm. Unless it’s a radical cam profile (which it doesn’t sound like it is), the next very common issue is a vacuum leak.

[@thorstencoates9255]

Question! For a 360 5.9L V8 small block. What size jets do I need for the carb. 0.107 inch, 0.098 inch or 0.089 inch jets.

[@MuscleCarSolutions]

Follow the tuning chart. Don’t make arbitrary jet size changes. Leave the stock rod and jets in and follow the changes on the tuning chart. I promise you that the results will be a lot better than making random changes.

[@thatguywithdt6110]

Great video! What could be causing my extremely rich idle on my 750 Edelbrock? I have fuel pressure set to 4-5psi. The AFR won't go leaner than 12 even with the mixture screws seated. It will get worse if I open them up. Can't close the plates all the way because then it will not idle at all.

[@MuscleCarSolutions]

How aggressive is your cam profile? What is your initial timing set to? And have you completely verified you don’t have a vacuum leak…. Any of those three could use the issue you’re experiencing.

[@thatguywithdt6110]

@@MuscleCarSolutions I believe the cam is stock, it gets around 18in of vacuum at idle. Initial timing is around 10°. Vacuum advance gives 20°. Have tried both ported and manifold. No difference except idle speed, still can't get it leaner tho. Haven't found any vacuum leaks.

[@MuscleCarSolutions]

@@thatguywithdt6110 well start with the easy stuff. I’d for sure put some more timing in it. I’m close to sea level and generally start at 12-14 with todays awful ethanol added fuels. If you’re higher in elevation, your timing will need to be significantly higher. 18” of vacuum is great! But sometimes the biggest number isn’t the best. A stock cam on a really good, efficient engine should bet that number no problem. If it’s a little worn, then you might have a happier engine with it adjusted for slightly less. Lastly is to close off the throttle plates. You’re likely into the transfer slots with a fairly high idle RPM. Close that down, reset the timing, start over on the idle mixture settings.

[@thatguywithdt6110]

@@MuscleCarSolutions I'm literally at the sea level myself. I have a stock distributor so I can't give it any more advance without modifications or it will ping. Total is 40° already. Don't know if the engine has ever been rebuilt. I could close the plates more but opening the mixture screws won't make it idle faster like it normally would. It will just get richer and worse.

[@MuscleCarSolutions]

@@thatguywithdt6110 so that leads to one last issue. You have a vacuum leak somewhere that’s demanding more fuel to go along with the air. 750 Edelbrock. On what engine? What intake manifold?

[@lyleleavell6200]

What about secondaries activating to soon? Is the weighted vacuum secondary sufficient to prevent premature secondary opening? I may be attributing a part throttle bog/gasp to the wrong system in the carb.

[@jessestone4650]

Question: if u are using a spacer/ elderbrock heat insulator spacer, should you richin up the mixture a little bit? Example get the most vacuum, for the best lean condition, and then Richin just a bit?

[@MuscleCarSolutions]

Reset if you feel it’s necessary. The engine will tell you if it wants more (or less) fuel. Remember idle is just a condition under 1000 rpm. Once you’re past that, the idle circuit is no longer metering the fuel the engine needs.

[@oleandreasjensen5263]

THANK YOU. You are an awesome teacher . - Its awesome to learn so much as I do with support from your videos.. Love these Edelbrock Carbs.

[@MuscleCarSolutions]

All I can do is show it. You’ve got to apply it and so the work so good job!

[@oleandreasjensen5263]

@@MuscleCarSolutions Well, In my opinion you do so much more than to show how these carburators works. Thank you for the insight I have learn from your very well done , and highly valued videos. Best greetings from Norway : )

[@MuscleCarSolutions]

@@oleandreasjensen5263 very much appreciate the kind words. Very glad these have been useful for you!

[@Wikkus]

Hi man! Great video, very useful. I've not had an Edelbrock carb before, but now I have one (a 1406) and I'm having trouble with it idling very rich (like eye-watering-standing-next-to-a-nitro-motor rich ;) ) My first step was, having read the manual and watching a couple of your other videos, to install a fuel pressure regulator -- this motor came with a non-stock Carter 0-2208 pump which, from what I gather, is most often used on marine motors. It was delivering 6.5psi, so I wound it back to just over 5, but it's still running rich. The motor is the original 350, but I don't really know the history of it and haven't opened it up to peek inside. What I do know is that it has an (older) Edelbrock Performer manifold, a pair of Trickflow aluminum heads, some long-tube headers, an MSD 6A, MSD billet dizzy, MSD coil. Cam is unknown, reciprocating stuff also unknown. Was seeing ~15"Hg on the vacuum gauge when I hooked it up, and it's running ~32deg total advance. My next step is going to be to pull the idle mixture screws out and check them. I don't have compressed air -- I'm just a guy with a single car garage -- would canned air suffice? Any other ideas gratefully accepted.

[@MuscleCarSolutions]

Before blowing through the idle mixture screws, I’d pop the top off and check for debris in the bowls. Blow through the needle and seats. Adjust the float level lower. Then blow through the idle mixture screws. Check the electric choke setting. Reassemble and check again.

[@mcanji3511]

Hi, what distributor is this on this motor? Do you have a pcv valve on the valve cover vacuum line? Thx

[@MuscleCarSolutions]

FAST HEI. No longer available. Yes I run a PCV.

[@frankg5177]

Great video but have a quick question, I have a big block Buick with a good sized cam 469 lift at 268 duration, Edelbrock 750 with Edelbrock B4B manifold with Headers the best I can do is 17" of vacuum timing is set to 15 deg at idle (no vacuum advance and I get a lot of needle bounce on my Vac Gauge assuming that is the cam, any thoughts on this situation?

[@MuscleCarSolutions]

Step up spring! Change to match that 15” of vacuum at idle. What’s happening is the spring is too light.

[@frankg5177]

Great I will open the hatch and see what they are doing and order a tune kit

[@frankg5177]

Forgot should I expect to see them sucked down or floating?

[@MuscleCarSolutions]

@@frankg5177 at idle the pistons will be down and steady there.

[@joseduranjr4963]

Any suggestions on adjusting a 2bbl carb on my 1979 Lincoln mark v with the 400 engine

[@MuscleCarSolutions]

@@joseduranjr4963 there’s not much you can do with the factory carburetors.

[@Cleanairmufflers]

I have a Ford M400 in my 1978 Ford Bronco and I am having trouble with vapor lock , will setting my idle screws to run on the richer side help to avoid vapor lock at idle ?

[@MuscleCarSolutions]

The issue is the poor quality fuel and ethanol. That’s what your fix is. Adding more fuel won’t cure it. Stock carburetor and intake?

[@dalejohnson3520]

Would you also use a air/fuel ratio meter to help with the adjustment. I use one on each bank to ensure that both sides are balanced and also use a thermal reader to check each cylinders temperature so that you get the most out of each cylinder. This also tells me if there is a weak cylinder so that I can correct an issue earlier instead of having a bigger problem later.

[@MuscleCarSolutions]

You certainly can but with a simple idle adjustment it’s really not necessary. If you see something way out the norm as far as lean or rich goes then you can compensate. But using a vacuum gauge is generally the easiest, safest way. Love the AFR for the rest of your tuning though!

[@fairlanephantom]

Transfer slots used to mess me up. Another thing I've come across is that highest vacuum isn't always the best goal for tuning. I've had better luck shooting for closest to stock settings. Spec on my engine is 19/20 inches in park, it can make 24 inches at vacuum, but you end up over compensating elsewhere to make that possible. I'm fine with just setting it to spec, I don't want to beat on an almost 70 year old engine too hard.

[@MuscleCarSolutions]

There’s something to learn from this. Sometimes a final setting at the highest vacuum is not the best. That can also reduce power and torque. There’s a happy medium here and one that isn’t always evident at the time of adjustment. That’s why it’s best to spend some time driving it to see how it feels and if an adjustment needs to be made one way or another. Good points!

[@fairlanephantom]

@@MuscleCarSolutions Yeah. Have some confidence in your adjustments or you'll never get out from under the hood.

[@Carburator_Ranger]

I appreciate it. 351 isn’t running like crap anymore

[@roadrunner0079]

Question ❓ I keep getting backfire it's a 302 Ford mustang 1968 could it be from the carburator?

[@MuscleCarSolutions]

Maybe. But I’d look at timing first. Then determine if you have a lean condition and why.

[@timgiesin4025]

Very good video you did a outstanding job explaining what you are doing and showing what you are doing

[@chicanoperez6377]

I noticed you had a spacer between the intake, manifold, and the carburetor, does that really help with warm start ups? Can you give me the part number for that? Thank you.

[@MuscleCarSolutions]

If you look at my other videos, I did one on heat soak and all the part numbers are in the description. Makes a big difference.

[@neilbrackstone6923]

Great video sir...I'm 2 days away from attempting this very deal however I noticed as my 350 is bine stock other than an I take and headers do I or would u recommend a pcv valve as of now I have not installed one thanks

[@MuscleCarSolutions]

Yes absolutely install the PCV. You need the crankcase evacuated to avoid further problems.

[@neilbrackstone6923]

@@MuscleCarSolutions thanks a ton for the info definitely subscribing to your channel

[@MuscleCarSolutions]

@@neilbrackstone6923 anytime. Always happy to help.

[@charlesmoore766]

Hello: Can you provide any 1406 with electric choke insight why rpm increases when I fully seat the LF mixture screw from 1 1/2 turns out? RH screw, no change from 1 1/2 turns out to fully seated. Fires right off. No vacuum leaks. All intake bolts tight, all plugs checked (changed 6 months ago), wires in good condition and full seated. Caped the four vacuum ports and the dash vacuum gauge showed same reading. Sprayed carb cleaner around carb base gasket no rpm change. Vacuum gauge on the carb ported vacuum showed zero as it should Sprayed carb cleaner into the needle openings and blew out with compressed air. Saw mist come out of the carb top. The tapered surface of both needles does not have a ridge but there are some rough spots. The tips look uniform 1971 Camaro with rebuilt 350

[@MuscleCarSolutions]

Lots of little things here, but start with this. kzbin.info/www/bejne/eqG4aKOMabGcaaM

[@charlesmoore766]

@@MuscleCarSolutions Watched the video, removed the carb, too much slot exposed. Turned idle screw out then in till throttle arm started moving. Mixture screws to 1 1/2 turns out. Turned fast idle way out. Electric choke guide set at midpoint. Installed w new gasket. Started but engine died well above 1500. Turned idle screw in 1/4 then start and died. Repeated till 1 1/2 in. Still had to keep foot on gas pedal (about 1,000rpm). Fully seated the mixture screws, started the engine and idled pretty good about 750.

[@MuscleCarSolutions]

@@charlesmoore766 good. Now give it some more timing. And come back to the idle speed.

[@charlesmoore766]

@@MuscleCarSolutions Isn't idle mixture still inoperative? I thought both needles fully seated would cause exteemly rough idle and the engine to die. Will additional timing and idle speed adjustment cause idle mixture to start working?

[@MuscleCarSolutions]

@@charlesmoore766 you said you got it to idle at 750. You’re not in the transfer slots at that point and the fuel is being metered through the idle circuit. So yes restricting the amount or fuel by turning in the screws could cause it to run rough.

[@tnposeys]

I have a new carb on my 78 Ford F150 351M. It's a 650 EVS2. When I turn the idler screws in, the rpm don't change and it doesn't kill the motor. On both screws. So, sound like you are saying I may already have some trash in the little slots. I guess I can take it off and check that. I do have a new tank, lines, and pump. But, it did have the old tank when we first tested it and noticed there was rust in the tank, so we changed all the fuel lines and tank out. I guess there could be some trash in the carb from that. When I idle and the engine has been running about 30 minutes, it surges a bunch off of a stop light. So much that I have to put on my emergency flashers for a bit until it gets back to running normal.

[@MuscleCarSolutions]

I’ll link a video that you’ll find useful. kzbin.info/www/bejne/eqG4aKOMabGcaaM

[@BiznessBoyProductions-FAM]

Does having the right adjustment help with a strong idle? My 74 nova, dies sometimes when i put it into drive, and ill have to keep the gas pedal down a lil bit and drive with two feet to get home.

[@MuscleCarSolutions]

What’s your timing set at? What’s your idle speed set to? What is your cam specs?

[@BiznessBoyProductions-FAM]

@@MuscleCarSolutions dont remember off the top of my head to be honest, id have to check specs again. Stage 2 cam with higher torque converter. As far as idle and timing nothing precise n exact was done if i remember right. It definitely needs to be fine tuned. If it was the timing though, wouldn’t it be a constant problem?

[@MuscleCarSolutions]

@@BiznessBoyProductions-FAM there’s several things that it could be but it will be impossible to point you in the right direction without any details. Have to know the cam specs. Have to know what converter you put in. What your timing is set at. It’s critical information you have to know if you’re going to have any chance of making changes in the right direction.

[@mrkwllms340]

I’ve enjoyed your videos. Just one question. When my AVS came out of the box, the idle mixture screws were fully seated (closed full right). On the BG carb the directions stated to open the idle mixture screws two full turns , then start the engine and work towards turning right (lean) to get the engine to run rough, then adjust back towards rich. Is there any guidance as to where I should process with my idle mixture screws?

[@MuscleCarSolutions]

On an AVS? 1 1/2 turns is a good place to start. Its plenty to get it started. First thing we talked about in the video is timing. Not sure what engine you're working on, but getting some timing in it will help you adjust the idle mixture and start the tuning process.

[@mrkwllms340]

@@MuscleCarSolutions I have 12degrees on a 73 Mopar 340. Thanks for the answer. I’ve been looking for a starting point to reference. I used 2 turns because that is what BG recommended for the Demon. 1 1/2 would have been faster.

[@MuscleCarSolutions]

Don’t be afraid to add more timing!

[@lazydaze9947]

On a Holley, some people say to crack the throttle plate so that you can see a tiny square of the transfer slot or about .025" of it. Then tune idle screws from there. Would you recommend to do this with an edlebrock?

[@MuscleCarSolutions]

Too many variables. There is no one setting for all. Doesn’t matter the flavor carburetor. I wouldn’t recommend that setting unless I knew the combination.

[@jordanisles9767]

Any thoughts about a ford 400 mild build nothing crazy 1406 carb always stinks of gas but recently I added an electric pump and it idles rough in gear but smooth as butter in park or neutral and runs great driving around. I noticed it before the electric pump but I’m seeing about 800-900 idle in park

[@MuscleCarSolutions]

All the normal things. Timing. Fuel system set up. Fuel pressure. Junk in the system/bowls.

[@dgiorgi1725]

Now this is the video I need to see, thank you. Great information content here.

[@elchapoyo]

I had to replace my stock mechanical Pump. I installes the new one, and also installed a fuel pressure gauge. And I am getting constant 3PSi. ¿is that enough fuel pressure for Carburetor AVS2 1906 model? Edelbr

[@elchapoyo]

I use this as a Daily Driver. Stock Engine

[@MuscleCarSolutions]

No. That’s likely not going to be enough to feed that carburetor unless you’re at a very low speed, low rpm, low volume use. 4.5-6psi is the range. Time for a better pump.

[@elchapoyo]

@@MuscleCarSolutions Thank You, I will buy another one for my 350 SBC. is there a Specific one you recommend for my Truck?

[@MuscleCarSolutions]

@@elchapoyo nope. One form a reputable supplier. Not sure what you have available to you.

[@mintypotato777]

well explained. would like to know how you mounted your fuel pressure regulator. looks really clean right there. so clean i cant even see how its attached lol

[@peterc2876]

Hi mate, Just tried this on my 600 Edelbrock with a new vacuum gauge (just finished installing fuel pressure regulator also), don’t know if my vac gage is faulty or that RH port on the carb isn’t functioning as the gauge didn’t move at all from the red area no matter which way I turned the idle screws. Am I doing something wrong? Any advice would be appreciated.

[@MuscleCarSolutions]

Ok first we have to be on the same page. Right hand is the passenger side of the carburetor. Remember it’s based on when sitting in the drivers seat. If you’re on the passenger side, that’s ported vacuum and you won’t see any vacuum on that port until the throttle plates open. You should be on the drivers side port for full manifold vacuum.

[@peterc2876]

@@MuscleCarSolutions Sorry, forgot to mention I’m in Australia with a ‘75 XB Falcon 351.

[@peterc2876]

… I plugged into the RH port as you look at the Carb so the same port you used in your vid.

[@peterc2876]

Just rewatched the vid, so do you adjust the main and fast idle screw right back so there is no chance of opening up the ‘off idle’ ports to ensure vacuum is at its maximum? Maybe that’s the problem?

[@nightingalelovr]

i have a carburetor for a 1972 dodge charger i replaced the full ignition system and it ran perfectly fine one done then i started it and it was running rich and it need a higher rpm to stay running but then whrn i would let of it would die then it started to steam from inside the carb whats wrong with it

[@MuscleCarSolutions]

Needs to be adjusted.

[@raylewis5570]

I'm trying to get this downloaded in my head. So I can be confident on doing this like normal. Thanks

[@MuscleCarSolutions]

Once you spend a little time hands on doing it, you’ll pick it up pretty quickly.

[@anomalous9448]

Thanks for this video. I noticed you are running the vac gauge off of the carb port. I have been using my manifold port. Can you explain the difference?

[@MuscleCarSolutions]

Yes. The vacuum gauge is there to measure the engines vacuum while you make your adjustments. The manifold vacuum port is below the throttle blades of the carburetor and will read full manifold vacuum. The timed vacuum port is located above the throttle blades. At idle when they are closed, no vacuum is registered. So to make the adjustment, you need manifold vacuum. .

[@anomalous9448]

@@MuscleCarSolutions thanks for the clarification. I have been using the manifold port for tuning but still my car runs rich with a strong gas smell. I tuned it for the highest vac reading (22) but I think I will back that off to 20 and see how that goes. Again, thank you for responding.

[@MuscleCarSolutions]

@@anomalous9448 setting idle isn’t tuning. Once you have that basic setting done, NOW you can start the tuning process to get the best performance and get rid of that rich condition.

[@terryharris9637]

Question,I keep my car in the garage,and I don't drive it much,but when I go to drive it,it hard to start also when I get it started after pumping the gas four to six times, when it starts the gas smells is very loud how can I fix this problem,I know it's adjustable but witch screws do I adjust?

[@MuscleCarSolutions]

Not much you can do. Ethanol added fuels tend to evaporate quickly. If it’s sitting for long periods of time, you’ll continue to have that issue.

[@briangray7614]

You can manually fill the bowl with a funnel. Just a thought.

[@Vxc6]

Once you done you done , this engine is done 👌🏽😎

[@raybinker9472]

At 14:02 my butt puckered seeing the bit stuck in the torx when her was checking the plunger springs...omg my heart skipped.. I had a helper years ago I was teaching on a bigblock in my Barracuda and he dropped a bit down the carb and BOOM new motor that just got broke in had to be RE Built again..ouch Great video btw!!

[@stuckinmygarage6220]

Ditto on the learning. Thank you. Here's one I think means something to an expert: I *think* I got it good enough to drive along. Then, I pull the brake vacuum hose and she ups 50-100 RPM?? Am I running rich? E-1406, mild Comp cam, 440, elec '74 ignition. Thanks.

[@MuscleCarSolutions]

It’s possible. Typically when more air is added one of two things happen. Runs rough or speeds up. 100 rpm is pretty noticeable. If you feel like it is getting a little too much fuel (assuming it’s at idle where taking about), you can add a little bit more timing and reduce the idle speed and or mixture screws. Just kind of a little trial and error type of thing but shouldn’t take too much time or effort. Here’s where an AFR really earns it’s money. You’ll know exactly what the output is and can quickly determine if your adjustments made the right changes. But in this case, I’d it starts easily, idles ok, doesn’t smell too rich and everything else is good, then I might not mess with it. But it’s a great observation!

[@nursecuenca]

I just tuned my small block 350 engine with mild cam. I have it set to idle at 800 rpm. Advanced settings 35 at dtc at 3000 rpm and idle 12 degrees before tdc. But when I placed vacuum meter on manifold port it comes at 14. It's the best carburetor can do after many attempts. Will running at 14 hurt engine? I would appreciate any suggestions. Thanks

[@MuscleCarSolutions]

Doesn’t hurt anything. If that’s all it’s capable of, no problem. What are the cam specs?

[@nursecuenca]

@@MuscleCarSolutions I bought if of someone. Not sure

[@cesarguzman6346]

I just got a new edlebrock preformer series 750 cfm, and I looked under and saw that the transfer slots were very exposed. I turned back both the idle and fast idle screws and nearly backed them out, but the transfer slots are still slightly exposed. What do you think that could be?

[@MuscleCarSolutions]

Could be a number of things. Bound somewhere. Return spring is weak/out of alignment. Getting stuck on the choke mechanism.

[@Wazoo117]

great video, but one question. how do you go about adjusting a reverse idle carb? like a Holley 7508

[@MuscleCarSolutions]

I’m not familiar with that carb. Is it one of the OE two barrels.

[@mickangio16]

@@MuscleCarSolutions there were Holley 4 barrel carbs from the emission era that the idle mixture screws adjusted the amount of air admitted to the idle circuit instead of how much fuel mixture that was admitted. Turning the screw out leaned the mixture. Turning the screws all the way in was as much as you could richen the idle mixture. I think I got a couple of them working satisfactorily many years ago by richening the secondary idle bleed circuit a bit to make up for the lack of adjustability. My opinion- don't bother with it unless you are a tinkerer and familiar with Holley carb. I think they may have used different metering block gaskets, too, which would probably be very hard to find now.

[@Diamondsintherubble]

So I’m new to tuning carburetors, I haven’t done one myself yet but I’d like to convert from efi, but would setting the idle higher like maybe 1100-1200 rpm cause issues with the fuel slots you mentioned or would I still be in a “safe” range? I ask because if the cam chops too hard for 800rpm, raising it would maintain the idle

[@MuscleCarSolutions]

Yes, anything higher than 1000 rpm and you’ll bypass the idle circuit and be into the transfer slots. If you’d like to check that, set your idle at the 1100-1200 on the car and then remove the carburetor. Flip it over and if you can see the transfer slots, you’re no longer on the idle circuit.

[@Diamondsintherubble]

@@MuscleCarSolutions okay perfect. Thanks for the solid advice

[@jhnyct]

I would love to hear your ideas. I have a 71 International Travelall with a 392 that I have been trying to dial in perfect with an Edelbrock carb. I started with a 1406 and determined the motor didn’t require enough cfm to activate the secondaries. I then bought a 1403 second hand. It has been great everywhere except the idle circuit. I can’t get any consistent AFR readings at idle. They range from 13.5 to 22.0. I am leaning toward a vacuum leak around the main shaft. Do you have any experience swapping the 1403 primary boosters to a 1406. The main body castings appear to be the same. My 1406 ran perfect in the idle, cruise, and primary power circuits. I know this is long, but I thank you for the time you have invested in your videos.

[@jhnyct]

I forgot to add that the idle screws have to be turned of 7+ full turns to achieve the best idle I can get.

[@MuscleCarSolutions]

@@jhnyct if you’re making that drastic of adjustments on the mixture screws, then yes you have a vacuum leak. No, you can’t swap the 500 boosters to the 600 and vice versa. Find your leak and fix.

[@jhnyct]

@@MuscleCarSolutions thank you for the reply. I’ll keep digging.

[@MuscleCarSolutions]

@@jhnyct I know it’s a pain but keep searching! What intake are you using?

[@jhnyct]

@@MuscleCarSolutions I am using the factory square bore intake with a 1/2” 4 hole phenolic spacer.

[@davidzaratee]

What bracket is that holding your gas cable? @2:15?

[@MuscleCarSolutions]

Factory one.

[@jackn5048]

Do the holley 4bbl secondary's add any fuel or air in the idle circuit? Or is the entire idle circuit fueled by the primaries only?

[@juliodiaz8280]

I have a 93 chevy c1500. What's a good spot to wire the electric choke?

[@MuscleCarSolutions]

I did a video on that topic for you. kzbin.info/www/bejne/lX_NqHmLf5WUl5o

[@Davian45]

What would cause an edelbrock 1406 to start out in a good AF range, but after 10 minutes highway driving (from cold) to slowly lean out to 18+ AF. Then after sitting for 30-40 min, the problem doesn't replicate on the highway drive back?

[@MuscleCarSolutions]

What’s your fuel pressure at when the lean condition occurs?

[@Davian45]

@@MuscleCarSolutions Tried installing edelbrock tubed fuel line with fuel gauge and it read 0psi period. Instructions say it can't be used with OEM fuel pump, so not really sure if the reading is true. I'm in the process of putting an inline gauge. Not sure why the edelbrock fuel rail couldn't be used with OEM pump though?

[@markmontes3469]

Amazing video! I’m 22 Tryna to learn how to do this on my c10 not many people in my area can do it.. If you do have a big cam, headers, intake etc, how much vacuum should you reach for? Also the springs bounce up and down on idle. Could it be the springs like you mention or the truck being not tune correctly? Thanks again!

[@MuscleCarSolutions]

If the springs bounce at idle, then you have the wrong ones. Measure your full manifold vacuum at idle and match up the corresponding spring. How much vacuum you can achieve is a moving target. Your engine will tell you what it’s capable of.

[@markmontes3469]

@@MuscleCarSolutions thank you big time! So I need to try to get the highest vacuum I can get. Going to try and re tune it since my idle has been dropping after I did a burn out.

[@leonardoagriel6207]

Perfect video where is you locate..?

[@captainshimmer7319]

Hello so the transfer slots are those little rectangular holes and I want them exposed before tuning the carb?

[@MuscleCarSolutions]

You want them covered by the throttle plates. Exposed will introduce fuel and bypass the idle circuit.

[@BrokePhilanthropist]

I have a fuel filter before and after my fuel pump,and it isn’t filling the top filter. Angle maybe? I’m getting a flat spot at the top of the peddle. Seems like it’s going to die when I down shift or slow down. Seems like it’s starving for gas. Tried adjusting the floats but no go. Seems better but not fixed.

[@MuscleCarSolutions]

What is your pressure regulator set to? What micron filters are you using? What is the pump rated at? Pressure and GPH?

[@BrokePhilanthropist]

@@MuscleCarSolutions just the two clear filters you used on the fuel filter video you made. It’s low fuel pressure I know it. I’m motor challenged,so I think I’ll try 2 less filters for the day. I have new tank and new stock aftermarket fuel pump. I need to do a pressure test. No regulator. Yet

[@MuscleCarSolutions]

For sure your next move is a regulator and gauge. Assuming the pump is in good order and is flowing the proper GPH, getting the pressure set is a priority. What’s your timing set at?

[@dennishouk4630]

That little torx bit coming off the driver could have caused some heartburn😊

[@MuscleCarSolutions]

0% chance. At idle, throttle plates are closed.

[@kimkaiser9426]

would this process be the same for a Carter afb on a 67 Pontiac 400??

[@MuscleCarSolutions]

Yes

[@ty6896]

So how much fuel pressure do you recommend? I think I see 5lbs on your gauge. I have a big block Chevy I need to do this on. What would be a good fuel pressure?

[@MuscleCarSolutions]

4.5-6 PSI is your range. Start at 6PSI and you can adjust down as needed.