CARB TUNING 101: Tuning basics explained!

How to setup up your carb so its ready to start right up after install. We apporach the basics of tuning the settings every beginner should know to mess with their old hot rod.
#projectcars #chevy #nova #carburetor #holleyperformance #holleycarburetor #tuning
~-~~-~~~-~~-~
Please watch: "I rescued this FORGOTTEN 81 International Harvester snow plow. WILL IT RUN? #projectcars "
• I rescued this FORGOTT...
~-~~-~~~-~~-~

[@princeomar140]

Before changing squirters you could verify that the accelerator pump linkage is adjusted correctly. Make sure that as soon as the linkage is moved fuel is shooting out of the squirter. Once you’ve set that you need to adjust the linkage so that there is a minimum of .015 clearance between the pump cam and the arm at WOT. Great video.

[@americannostalgiagarage]

Absolutely right. Thank you for mentioning that. Can’t believe I forgot to mention it. And thanks for watching.

[@walterpatterson3205]

@@americannostalgiagarage

[@SyracuseIsOranges]

My brother and I didn't know where to start. This was extremely helpful and simple to follow

[@americannostalgiagarage]

Very happy to hear that this help you guys out. I hope you get your hot rod up and running real soon. Thanks for watching.

[@farbeyondriven6562]

Just purchased this same Carb for my 69 Judge. This weekend will be the install. This video will definitely help me!! Thank you for the video. I will follow these steps and let you know how it turns out! 🤜🏼🤛🏼🔥

[@americannostalgiagarage]

Definitely a good purchase. I’m happy with mine. I will say that you should pay special attention to getting the float height correct on this carb it seems to be even more temperamental when it’s not correct than normal carbs. Thanks for watching.

[@kernskimarshell7153]

Thank you for the great video. I just got done putting in my 455 with a QFT carb. Can’t wait to adjust it. Keep the videos coming.

[@americannostalgiagarage]

455?!? That a big ole engine. Hopefully you get it going soon. Only addition I would make. The sight glasses should have fuel half way up the glass. I’ll like to put that edit in the video but I’m not very technologically advanced. Hahaha. Thanks very much for watching.

[@TheGorf]

I think it's worth pointing out that the glass sight floatbowls have specs per Holley documentation that the fuel should be in the MIDDLE of the glass. The "bottom" is only for the old plugged style ones. Additionally, vacuum tuning is so archaic. Just put an O2 bung in and use a hand held meter and tune for AFR.

[@americannostalgiagarage]

Thank you for making the correction on the sight glass. I certainly agree that adding an o2 sensor to a vehicle is a better way to do it in every sense however many people running a carb are not going to do that. Which is why I included it in the video. Thanks for watching.

[@danielhindssr6159]

Thank you for the explanation very informative. Takes a lot of mystery out of the tuning a carb.

[@americannostalgiagarage]

That was exactly what I intended to do. Thank you for the kind words and thank you for watching.

[@SuperDave227D]

Love this! You made it much clearer and more understandable on carb tuning!

[@americannostalgiagarage]

Very happy to hear that it was helpful to you. Thanks for watching. Spring is here I hope your hotrod is almost ready to drive lol

[@matthewhummel6023]

Very informative, well done. Holley 650 HP alum. on a 66 Sunbeam Tiger, 289.

[@americannostalgiagarage]

Wow a sunbeam that’s not something you see everyday. Very cool. Hopefully you’re almost finished and getting to drive it this summer. Have fun with your hot rod. Thanks for watching.

[@chrismadeley1971]

Nice straight foward explanation👍

[@americannostalgiagarage]

Thank you for watching!

[@BPattB]

Holley cow man, thank you so much. I was using the wrong vacuum port, lol. I have been looking for a good 40 minutes until I found your video addressing the Brawler vacuum port. Thaks again!!!!!!!

[@americannostalgiagarage]

Very happy to hear it helped! If you have a vacuum gauge it’s worth testing the port to ensure it’s full manifold vacuum and not ported. For reference full manifold will he high at idle or cruising with the throttle blades closed and go to zero or around zero at wot. Ported will be low at idle and increase as you open the throttle blades because the source is above the throttle blades and works with a Venturi effect as they open. I’m sure you already know that. Just trying to be helpful. Thanks for watching.

[@c.sherek3792]

Excellent video…Easy to understand! Thanks!

[@americannostalgiagarage]

Glad you enjoyed it. Thank you for watching!

[@tedslife7086]

I left my Holley XP at 1 and half turns and my 496 runs great!

[@americannostalgiagarage]

Awesome glad to hear that’s a big cube engine I bet that thing is a beast. Thanks for watching.

[@darkwolf4962]

I must admit, the info you provided is not only the best, but also the easiest to understand. I have been dealing with a Barry Grant 650 Demon quad and it's delivery issues . Most others have advised to replace it with another carb that isn't a Barry Grant. I'm stubborn and actually like the carb. So with the info you provided, I feel much more confident about getting my 79 Elco up and running. I have a 350 small block in it. I will post my final results regardless once I have finished. Thank you for taking the time to share and care. And, yes I am now a subscriber. Peace

[@americannostalgiagarage]

Thanks A lot for the kind words. Really happy to see you got something of value out of the video. Barry grant carbs are good to go. Although the easy way would be to replace hood parts with new stuff but taking the time to get your old stuff going is more rewarding and it’s a great learning experience. Thanks again for watching. Please post results when you’re ready can’t wait to see it.

[@michaelyoho4848]

Great info and thank you for sharing your knowledge.

[@americannostalgiagarage]

Thank you for watching. Glad you were able to get some value out of the video.

[@richie9285]

Video was very informative I'm wondering if you can help me with tuning the air bleeds which I have on my Brawler, TY very much.

[@americannostalgiagarage]

Hey Richie. Thank you very much. So what’s going on with your carb? What makes you think the air bleeds need tuning? For reference the air bleeds help with emulsifying fuel and stop the carb from overpulling fuel. How’s the car running?

[@thedobermangang3503]

very good video my brother you would be a excellent instructor..

[@americannostalgiagarage]

Thank you very much. I appreciate that. And thank you for watching.

[@chrisgeorge6321]

great vid. lots of good advice

[@americannostalgiagarage]

Thank you. I really appreciate the comment. And thanks for watching.

[@st.k.4528]

Thank you for the video, what about adjusting the rear butterfly openings? I know my holley has a screw to adjust them.

[@americannostalgiagarage]

That’s a good question, I did not look actually. This engine has a boost cam in it from its last “assignment” lol, so I didn’t need to mess with the secondaries. Holley sells a kit to adjust the secondaries without having to take the carb off and flip the carb over just so you know. It’s worth the frustration. Thanks for watching.

[@st.k.4528]

@americannostalgiagarage yes, my secondary was opened alot by previous owner because when connected to ported/timed vacuum he could not adjust idle properly. I switched to manifold vacuum, got 20 timming at idle and closed secondaries and primary down. Works better.

[@americannostalgiagarage]

@@st.k.4528 that’s great. Many people would have not known what to do in your situation great job getting it all figured out!

[@waynemccarthy2299]

Thanks for the video. I have a 750 Proform carb. My new rebuilt engine is running way to rich. Any thought of what I should do?

[@americannostalgiagarage]

I would start by asking when is it too rich? Idle? Part throttle? Wide open? I would get for idle mixture screws set first those are usually a culprit. Next would be jet the carb down a couple sizes (2 or 3 sizes at a time). Also make sure you dont have too big of a squirter in there. After that we’re talking power valves, air bleeds and a bunch of stuff.

[@waynemccarthy2299]

When I start the car up the way the carb is set now; and drive it for a while. After turning the car off and trying to start it again it won't stay running. Pull the plugs out and all of them are fouled. When I first take off with the car it hesitates for a second before taking off. I have never messed with carburetors, but I have to learn now. I moved out of state where my buddy use to do all of adjustments to the carb.@@americannostalgiagarage

[@mickangio16]

I would suggest reducing the idle feed restrictions size such as .032" to .028". If your idle mixture screw adjustment is as little as 3/4 or even less turned out, that is a good indication that the IFR size is too big. I like to shoot for 1-1/2 turns out. If you find your idle mixture screws needing 2 turns out or more, the idle feed restrictions are too small. That's when you start having problems tuning the accelerator pump system.

[@Ven0mcamaro-383]

Video I needed to find. Can you make one of using a wideband to select the proper size jets

[@americannostalgiagarage]

That’s a great idea. I will definitely pin that on the idea wall for when I have a little more room in the budget. Thanks for the idea and thank you very much for watching.

[@tedslife7086]

I left both float glass just at the bottom were you can just see it above the bottom of the glass

[@327365hp]

Nicely done!

[@americannostalgiagarage]

Thank you very much and thank you for watching.

[@garyhelms1889]

Geez. Now I have to go to Red Lobster. Oh yeah, Thanks for video.

[@americannostalgiagarage]

Hahahaha. Nothing better than a good meal. Thanks for watching!

[@allenmeinhold7038]

Great video, Thanks Buddy

[@americannostalgiagarage]

Thank you Allen. I’m glad you enjoyed it. Thanks for watching!!!

[@markferguson9981]

how to adjust air flow my truck runs on when i shut it off also alot of condensation out of tail pipes

[@americannostalgiagarage]

So first the about the condensation out of the tailpipe. H20(water) or better yet steam, in small amounts is a by product of combustion. So if you see a little bit when it’s cold or on start up. Or is you see a small about of liquid coming out of the tail pipes here and there that’s ok. But if you’re saying you have a substantial amount of water coming out of the tail pipes, then I ask what does it smell like, sweet? Then it may be coolant and you may need to be looking into head gaskets, possibly. As for it running on, that could be caused by a couple things, a leaky carb that’s allowing fuel through when it shouldn’t be, I’d also check the timing. But you could also have a hot spot in the engine, gasket or heavy carbon deposits that could be causing it to have pre ignition and to diesel on like you’re describing. Side note if this is a high hp engine or high compression and you have old or low quality fuel or even too low an octane it could do the same thing. That’s a few of the possibilities. Good luck with it, I hope you get it fixed soon.

[@sixstringcity3931]

Big thanks

[@americannostalgiagarage]

Thank you very much for watching!

[@jacobgamble5044]

Thanks for the video I'm struggling with my 680cfm Brawler can get it to start but if wont stay running long enough to even verify timing feels like it's going to shake itself apart. Got vacuum advance pointed at number 6 cylinder.Both corners are 1 1/2 out throttle screw is bumped up almost too much at this point where the engine diesels when shut off. Where am i going wrong?

[@americannostalgiagarage]

In this case I would take a little breather. Then go back to basics. Verify too dead center, verify you have the firing order correct. Verify you’re not over advanced(would probably be hard to start) check the plugs to get an idea what the mixture looks like, probably replace them. Make sure the valves are adjusted ok. Then make make sure your carb is doing it’s job, fuel leaks, vacuum leaks, readjust idle mixture screws and make sure you don’t have a leaky power valve or another circuit isn’t fueling when it shouldn’t be. While it’s running look down the Venturi and see if you can see fuel “dribbling” out anywhere. I’m sure you will figure it out. Stick with it. Thanks for watching.

[@rickyj2013]

Hey buddy I like that screwdriver with the strike cap on the end of it where is that from?

[@americannostalgiagarage]

Hey, I got them at summit racing. Probably my favorite set. My son steals all my screwdrivers so I go through them like water. Thanks for watching.

[@waynemccarthy2299]

Should I set my float halfway on the site glass or just when I see the fuel on the site glass.

[@americannostalgiagarage]

I’m not much of an editor to fix the video but the correct way is halfway up the sight glass. It should be noted that if your carb has removable plugs like the Older style carbs do then the bottom of the hole would be correct. Sorry for the confusion. Thank you for watching.

[@isaacjamison7723]

This is great content . Ty

[@americannostalgiagarage]

Thank you the compliment, I’m glad this helps. Thank you very much for watching!

[@supernaut1029]

I’ve got a Chevy 2 also with a quick fuel carb. I have a problem with a rich idle. Any ideas what I can check for?

[@americannostalgiagarage]

That’s great what year is your Chevy II? I’d start with the idle mixture screws. After that I’d verify the floats aren’t too high and you’re not dribbling fuel out when you don’t want to. And mess with the air bleeds, if they’re adjustable. Those have everything to do with how fuel is pulled from the bowl. But start with the mixture screws. Thanks for watching.

[@supernaut1029]

The site glass level is in the middle. The rear set screws are at 3/4 turn out. It’s a QF 680VS on a 383 SBC

[@americannostalgiagarage]

⁠@@supernaut1029 how are you deciding that it’s rich? The old sniffer? Lol. If so, could it be that the front idle circuits are the ones that are causing the fuel smell? Also keep in mind that the amount of throttle opening is also going to effect the Venturi effect on the fueling circuits. So it could be open to a point where it starts switching circuits.

[@supernaut1029]

@@americannostalgiagarage definitely smells rich. I have the front set at 1 1/2 turns idling about 1000. It’s not a big cam but the LS is 106. I have a 66 Nova. Would send a pic but not sure how to do it on KZbin 😂

[@americannostalgiagarage]

@@supernaut1029 that LSA is probably not going to be as easy to tune at idle with a choppy cam like that. I bet it sounds awesome so good for you on that. Lol. With an LSA like that your volumetric effieciency is probably pretty bad because there’s probably not a lot of scavenging and maybe some exhaust reversion. So your rich condition could be caused by a little bit of incomplete combustion at idle. However you might be able to bandaid that by setting your front idle screws in a half turn and maybe bumping the idle up by a couple hundred rpm. And maybe smaller slow speed air bleeds. Either way that thing sounds like a good time brother. Just roll with the fuel smell on that beast. Tell people it’s your new cologne.

[@thedobermangang3503]

when you changing the power valve do you have to change the jets at the same time

[@americannostalgiagarage]

Good question, no you don’t. The power valve has more to do with timing the additional fuel for wide open throttle. Not as much to do with air/fuel ratio although it does effect your afr. You should decide your jet changes depending on spark plug readings and on how the engine runs. It can be tough sometimes. Usually it’s best to jump 2-3 jets sizes and see how the engine likes it. If it gets worse you could try going the other way. Thanks for watching.

[@dave85oldschoolmonte]

I am having trouble with fouling plugs it is running to rich I have a 750 brawler on a 383 signature series motor

[@americannostalgiagarage]

Probably worth jetting it down. But that’s sort of a blanket statement type repair. 383’s are awesome power plants. But shouldn’t need a ton of jet. Try jetting it down 3 numbers and see if that helps. Thanks for watching.

[@nwmod39]

Fouling/rich at idle or cruising?

[@rodrigogarcia1296]

This work for any kind of carb? Have an edelbrock 4 barrel

[@americannostalgiagarage]

Yes and no. The principles are the same however an edelbrock is adjusted differently because it’s a different design. Thanks for watching!

[@automotivechaos]

Red lobster sounds great!

[@americannostalgiagarage]

Unfortunately I couldn’t convince my family to join me.

[@automotivechaos]

@@americannostalgiagarage just call Dom Terretto next time.

[@menoaz]

I wish there was a video for carbureted supercharger guys. I got two blower carbs on my 6-71 and can't keep the plugs clean after I race a couple times. No matter how much I lean it out.

[@americannostalgiagarage]

That’s an entire video in its own lol. That sounds like an awesome setup you have there. It’s been a while since I had a carbureted blower car, but man do I miss it. Mine was a draw through roots blower with a boost reference Holley 750 double pumper. It was lots of fun but always ran rich. Enjoy that thing. Thanks for watching.

[@menoaz]

Sounds exactly what I got but mine is a 427 big block Chevy with good heads and a solid flat tappet cam. ​@@americannostalgiagarage

[@americannostalgiagarage]

@@menoaz that thing is probably a beast. How many psi of boost is it making?

[@menoaz]

I'm only running 10 lb of boost because I like to run it on pump gas. It still runs 10.90 on my 3200lb Camaro. Wish I didn't have to change plugs so much.

[@americannostalgiagarage]

@@menoaz I would mess with the heat range a bit. That should help keep the plugs cleaner.

[@vicc6744]

So which vac port did you use and what if when you do the adjustment NOTHING happens?

[@americannostalgiagarage]

You need to use the full manifold port not the timed port, once you throw the gauge on, full manifold will read vacuum and drop when the throttle is opened. If you make an adjustment and nothing happens then either you’re right on the money or you’re so far off that you may need to make large adjustments to see a difference. It comes with time. You can do it though, just stick with it. Don’t make more than one adjustment at once. Thanks for watching.

[@ceasergert2780]

I need advice have great curb idol. Then I drop it in gear and it drops way down just about killing the engine so at a corner have to put it in netursl

[@americannostalgiagarage]

So I would want to know what transmission is in the car. Basically want to know if it has a lockup converter. Possibly the converter is stuck locked. But if not I suspect a vacuum leak, or fuel delivery issue. Basically it’s probably running but doesn’t have the power to get over the load of being put in gear because it’s not getting enough fuel or there’s an issue with the trans. Also double check your timing. If the trans is ok, check your fuel filter, the screens in the carb inlets, if you have them, make sure the needle and seat is clear. Buy a can of carb cleaner and spray it all over to try and find a potential vacuum leak. Try these things to start, I bet you find it pretty quick once you start looking. Thanks for watching.

[@ceasergert2780]

@@americannostalgiagarage thank you so much off to buy carb cleaner

[@americannostalgiagarage]

@@ceasergert2780 of course, check back in when you find it I’d love to hear how you do with it.

[@num1islesfan35]

When's the footprint gas pedal going in?

[@americannostalgiagarage]

My cars in the shop getting a foot print gas pedal installed, so I stole this pile. - joe dirt.

[@dorinschatz5457]

Thought this illustration was great for me to fine tune my holly 4 barrel

[@americannostalgiagarage]

Thank you very much for the compliment. Glad the video helped out. What kind of hot rod are you working on?

[@dorinschatz5457]

@@americannostalgiagarage i had to replace my motor on a 1991 1500 , had a option to put a 350 ci high performance engine in here but had to get rid of the port injection and go old schoot like me . My 350 cu is putting out 425 HP , i was 26 in 1991 when bought new. I paid 16,500 for here , had her appraised 2022 in fall 38,500 no rust orginal paint

[@americannostalgiagarage]

@@dorinschatz5457 Wow the appreciation of these old cars and trucks is crazy. Amazing to see how much money you could make. Keep truckin'.

[@vrm86gt]

thanks!

[@americannostalgiagarage]

Thanks for watching!

[@lordsauto]

U have roller cam in that car?

[@americannostalgiagarage]

Yes sir.

[@BWo-bb1yw]

good

[@americannostalgiagarage]

Thanks for watching.

[@rogerstill719]

POWER VALVE 6.5 to 8.5

[@americannostalgiagarage]

Yes definitely. Thanks for watching.

[@bobdimartino6738]

it's a holley brawler it's made by holley

[@americannostalgiagarage]

Yup. I know

[@gearheadmoff1232]

Quick fuel design just bought by Holly..actually it has a proforma center..

[@bobdimartino6738]

@@gearheadmoff1232 so it's a holley everything about the quick fuel inside is what holley has made from day one

[@bobdimartino6738]

2 and a half out to start

[@americannostalgiagarage]

I’ve never heard that before it’s always been 1.5 but if I have issues I’ll try this thanks

[@bobdimartino6738]

@@americannostalgiagarage you're welcome i've heard 2 and a half on all carbs your the first i've heard on 1 and a half also i use the afr wide band to adjust takes the guessing out. i have one on each bank i bought a triple gauge holder i have one afr on each side and a vacuum gauge in the middle inside the car

[@americannostalgiagarage]

@@bobdimartino6738 ok well I’ll keep it in mind if I ever have issues the 1.5 turn method I’ve been doing for almost 20 years and has worked perfect for me. But you learn something new everyday right?

[@philipchesser8889]

All of these videos are 20 mins long is there no way to explain this in a short video.

[@americannostalgiagarage]

I would say yes there’s definitely a way to show the adjustments in a shorter form. The only issue is then you would need to leave out all the theory, and the theory is necessary to understand why and how to make the adjustments properly. I wanted to try and be as thorough as possible. Thanks for watching.

[@stunnindunning]

Johnson rods 😂

[@americannostalgiagarage]

Johnson rods are always recommended in this model. Lol. Thanks for watching.

[@earlbrown]

I wonder if that wrong ''cut the idle vacuum in half for your power valve'' myth will ever die. Lean cruise and idle have zero to do with each other.

[@americannostalgiagarage]

Seems to be a general rule of thumb that has gotten people in the ball park for a long time. Plus really getting into power valve tuning is above most weekend gearheads abilities. Just trying to help those guys out. Thanks for watching.

[@earlbrown]

@@americannostalgiagarage Yeah, it's crazy people can't tape a vacuum gauge to the windshield and literally look at the needle when the car misfires at cruise. It's literally the easiest thing to sort out (correctly) in the carb. It's not like something 'complex' like realizing the main jet is for cruise not WOT. And the power valve channels are for the rest of the fueling at full throttle.

[@americannostalgiagarage]

@@earlbrown its not crazy but i think that’s mostly above what the average gearhead knows to do. Thank god for people like yourself who know enough to pass along the extra knowledge and experience. Again thanks for adding the much needed info.

[@darringrey4329]

A lot of old fashioned tunnig , need to get with the times , carb tunnig has moved on from most of what you show

[@americannostalgiagarage]

There’s no trick about setting up a carb. Regardless of what year it is, setting float height, idle mixture, and so on never changes. However, what you might be referring to is manufacturers changing the carb itself which may require different tuning methods or settings. Ever carb is not the same. But every one of the “old school” methods still works perfectly fine for most Holley type carbs with some minor adjustments for design changes ie sight glass on the fuel bowls. But the fundamentals still work for EVERY carb. We change physics even if we wanted to. A carb is still a carb. Thanks for watching.

[@cosimosanfilippo9050]

Bla, Bla, Bla........

[@americannostalgiagarage]

Cool thanks.

[@darkwolf4962]

Can't please everyone

[@Profabdesigns]

Terrible presentation and over talks a simple thing.

[@americannostalgiagarage]

Thanks for you input.

[@Brooks336]

Hmmm went to your channel & didn't see where you've made a video on how to tune carbs so your 12 subs would know how to do it.

[@darkwolf4962]

Haters gonna hate. I suppose you think you can do better. Think before you say something stupid

[@Profabdesigns]

@@darkwolf4962 I’m guessing your the keyboard expert here huh. Funny thing is, I have the registered patents to back up my ‘stupid comments’. I’m not afraid to say I don’t know everything. But if I make a comment you better damn well know I know a little something about it. Unlike you I’m no snot nosed puke 🤮

[@michaelgarrow3239]

simple for a genius such as yourself- it is called broadcasting for a reason… 🙄🎶🎵