How Quadrajet hot-air chokes work

There seems to be some mystery about how to get these old hot air chokes working again or working better. In this video, I use a complete mocked-up assembly to show you the parts to those systems and how they work.
These are commonly found on '76-80 Chevy V8's, and most years of Oldsmobile and Pontiac V8's.

[@kenromaniuk1777]

WOW ! By far the very best video and explanation on this ! Thank YOU Tyler !!!!

[@TruckThisGarage]

Man I’ve been looking for this video for a long time

[@TruckThisGarage]

Finally an explanation and I can finally hook my carb up correctly 😂 🎉

[@billbaker8685]

Thanks ! was scratching my head on how this worked- the service manual was no help

[@briansd2772]

Thanks for this video. Simple and effective system directly reacting in real time to what the engine is telling it.

[@jackr244]

Thank you WST! This is a great video and I appreciate your clear and impassioned ( I loved the "No! No! No!" ;) explanation. I've got a 1966 Tempest and I'm working on getting the choke correctly set up and behaving correctly. This video was really helpful. Please keep sharing the QJ love! Jack

[@gravysnakes]

brilliant, many thanks. so helpful. I am researching why my car stalls when cold and this is the answer. (1978 Trans am)

[@subarutruck1]

Thanks sooooo much! I have a 57 Ford Fairlane 500 with 292 that you helped me fix. Your right, this is probably the only video that addresses this. I can’t thank you enough!!!!!!!

[@shawnfoundation3926]

This was a pleasure to watch!

[@brianwelteroth9248]

Thanks for the simple yet thorough explanation.

[@TylersNeighborhoodGarage]

You're welcome!

[@genokearney]

Thank you so much for this. It is still relevant today for restoration. In my case, a 1976 350 Camaro.

[@germanium1872]

Thank you for the video. It was so hard to find information about these choke tubes.

[@TylersNeighborhoodGarage]

Sure thing.

[@briankeery1]

Tyler, thank you so much for taking the time to explain this in such depth. I had my original 1979 Corvette carburetor rebuilt a few years ago. The unit was engine tested with all new parts and a detailed description was sent back to me with the unit. In that description, I was given high and low idle settings, AF settings, and told that choke had been set. Since it was reinstalled, the car has ran flawlessly except for the choke coming off high idle. I've seen engine temps on my gauge hit 175F and the car still idle at 1700 rpms - even after hitting the gas lightly. It will come off if the car is revved to about 3500 rpms. Usually I have to put it in gear and once I've accelerated into second gear and gone about a block, she's always at a proper idle of 600 rpms when I'm sitting at the stop sign at the end of my block. I've verified that all linkages are free, and was concerned about messing with the choke coil, since I'd paid to have it set up. I had to ship the carb away for the rebuild, so sending it back wasn't really an option. Other than the initial cold start issue she runs great. This definitely gives me something to check .......so thanks again, subscribed.

[@TylersNeighborhoodGarage]

Thank you for the kind words. Your issue is likely the choke coil is set slightly too tight(rich). Don't be afraid to tweak it if needed. Remember that life with a carburetor is not like fuel injection where everything stays constant. Periodically the idle mixture screws may needed fine tuned, a vacuum line replaced, the choke adjusted a bit, that's just the nature of the beast.

[@75hdfxe]

Thanks for posting. Always wondered how these worked.

[@torontochris9]

So helpful thanks! I just found a severed tube in my manifold for a 73 Matador. My choke hasn't worked well for years! This video also applies to my 232 straight 6 with Carter YF.

[@Specialized61]

Thank God I found your video. I just rebuilt the 350 on my 79 Gmc and had the carb rebuilt as well. I'm having problems with cold starts . The choke plate does not seem to be opening as I think it should. Seems to be sticking closed

[@jcass9399]

Thank you real helpful. How do you close the butterfly valve tight? Appreciate you thxs

[@kimmijohnson1320]

loving that mopar in the back ground there bud lol

[@RestorationObsession]

Perfect explanation! Thanks for posting this.

[@bebobism]

Mmm . . . I was wondering about this. Looks like I've got some problem solving to do , there's no heat crossover on my manifold. :) Thanks for the video.

[@YoloMaBrolo]

I have the same problem did you find a fix

[@nathanstevens2664]

Thank you, this was hard info to find

[@mrbrocephus3849]

Dude you opened my mind. I have a 75 caprice 4bc 400 small block. 👍👍👍👍👍

[@TylersNeighborhoodGarage]

cool!

[@davidfriedly1539]

Great great lesson and cut away thanks

[@Dougie33]

Thank you!!! My engine is completely missing all that plumbing

[@bonebone9008]

Thanks for the video. I wondered how this worked

[@materialdialectics]

Thanks for this, 'choke stove' tube has been broken at the mount bracket thing and I've been wondering what actually goes on down below there before I dig in.

[@TylersNeighborhoodGarage]

Glad I could help!

[@droptopchevy]

Thanks for the Video. Are all Quadrajet hot-air chokes factory set for 1 notch lean?

[@jonbennett118]

everything i learned out about my TA's quadrajet i learned from you. Way up here in Canada!! I have a Trans am that starts immediately and purrs like a kitten thanks to you Tyler. I also pointed a stranger from Kijiji to your youtube channel (he was looking for someone to rebuild his quadrajet), and he wrote me back and said thanks your videos helped him tremendously. So if you ever wonder if what you teach is being used and absorbed.. well there ya go. ps .. what happened to the cutlas?

[@TylersNeighborhoodGarage]

Thanks! I'm trying to spread the Qjet love...lol. Youy now know what I mean when I say these carbs are the closest thing to fuel injection, when they are properly maintained. What kind of TA do you have? I sold the Cutlass. I wanted an older Chevy truck.

[@jonbennett118]

WhoSaidTyler I have a 1980 TA with a 79' Olds 403 and 79 carb. I missed the video where you talked about finally getting that cutlass sold. I know you had it trouble getting a buyer. I have been watching the truck videos and enjoying them. Thanks again.

[@jnray094evr]

Great video thanks so much. Question, I'm workin g on this problem haven't gotten to the intake choke pipes yet to see what it looks like inside yet. But, behind the choke underneath someone tied a thin metal wire around one of the of the levers and it must of broke off but why do folks do that instead of replacing the part? Anyways I'm gonna keep looking and wanna thank you again for your videos. I'm working on a 1981 Chevy C10, 305, w400 trany. This truck ran pretty good till something made it lock out the choke plate on top. I may need to replace a couple of things but without these videos and some reading it can't get done sometimes. By now, JR.

[@gustavette8487]

Great video. My 1978 Corvette came with an electric choke, but still has a tube coming out from the rear, that plugs into the bottom of the carb instead of the manifold, next to the choke. Then is another tube that comes out next to where the 1st one is plugged in and it and goes to the front port on the carb, where your tube is plugged in, BUT mine is not plugged in since that port is plugged. I guess that this choke was "converted" to an electric one and therefore, those tubes are not needed now. If so, can I just take them off N and plug the ends where these tubes were originally plugged in to? Thanks!

[@Robin_Gobblin]

My choke lines are rusted broken, I’m having a hard time finding replacements, any advice where to find?

[@ryanwilliams3369]

can this setup be converted to manual

[@kellenstuart4698]

awesome video. thank you. Trying to figure out the 1985 Ford F150

[@TylersNeighborhoodGarage]

That may be one that has a choke that is hot-air with an electric assist.

[@malc1012]

Is this a better choke vs the electric choke? I’m new to quadrajets and I’m planning to buy one to replace my holley carb

[@DEEPMINDMYSTIC]

What are the symptoms of this failing as far as when the car is running

[@andymalanga]

Great vid! What do you think about the choke sticking closed every once in a while. I can drive for hours with no issues on some days. Other days I go 15 or 20 miles and it loads up and stalls and won't start. When I pulled the air cover could see the choke closed tight and would not stay open even if I opened it manually. Any ideas?

[@angelcastro3714]

Hello good video about the carburetor hey I have gmc Classic sierra 1986 is stall on reverse or drive do you think I missing air somewhere like you just show on the video

[@zXStrykerOneXz]

I have a 1978 Buick LeSabre Buick 350 has new engine but the automatic choke doesn't turn off it stays on I'm under this is something to do with that

[@John87219]

I just ordered a new choke wire, and choke connector for my 83 Buick Regal T-Type 3.8l v6 231cid. Turbo Charged. Also ordered a choke pull off and throttle return spring. Could I just try to adjust the choke? My buddy and his dad rebuilt my carburetor, but its still acting up.

[@86mcclanahand]

I have lost my choke stove and also wanted to know how or if the replacement kit from O'Reilly work? (Choke Stove Kit Part # 03840)

[@TylersNeighborhoodGarage]

Well...in a pinch I guess. You can still find those choke stoves in the junkyard or on eBay.

[@arthurmoore1524]

Hey guys I'm having a problem with my q-jet getting stuck wide open. You can give it some gas, it'll do fine and come back down to idle But when it comes back down to idle, it slowly starts climbing rpm, and getting stuck wide open

[@colterino422]

Is this the same on a Dualjet? I have a two barrel Dualjet on a 1977 4.9 that wont start. The choke wont turn and has been chipped away at before. I'm probably going to break the rich/lean plastic piece trying to get it to turn. Any ideas?

[@danb9744]

Great video. I have a 84 Chevy truck with this same design but my choke does not have the choke housing hose connector so I have no way of connecting it. Any suggestions?

[@TylersNeighborhoodGarage]

Are you saying that the engine has the hot-air choke system in place but the carb is different? Hmm. Makes me wonder what changed...the carb or the engine under it. I'd check the carb number to see whats up if you are curious but I think you can change the choke housings around too.

[@buckster2575]

Have a hot air choke on a holley.i want to convert to electric choke. Advice on what to go with

[@cristianayuso1146]

sucks air when regulating, I have to put the choke to make it work

[@tonyk6832]

Do I have to take the manifold of too check if it's broken

[@TylersNeighborhoodGarage]

No. The assembly unbolts.

[@JoseLopez-hp7rj]

What is the name of the tube type part the goes around the part?

[@cheeriosdelgado7598]

What happens if I don’t have a place for a choke stove?

[@TylersNeighborhoodGarage]

You'll have to use an electric choke. Keep in mind that not every engine used a hot air choke. Some Buicks, Cadillacs and Chevies used electric chokes.

[@1ggssxxrr]

What the hell I never had the heat tube in my manifold

[@LKRS111]

What if the "Choke Stove" metal lines are backwards? Will that cause it not to idle down all the way? Sbc 350.

[@TylersNeighborhoodGarage]

It shouldn't. The main thing is that the hot-air system is leak-proof.

[@Mindgauge]

Question if your heat choke is connected to the carb but is caped on the other tube instead of it being connected to the carb like yours , how does it affect the carb/ car? I know it's a dumb question . I have that carb on my 77ta and it's just like I said.

[@TylersNeighborhoodGarage]

It doesn't affect it in any way. Capping it just renders it non-operational. It's pretty easy to get those going again, just remember the tube has to be airtight.

[@michaelpeterson4348]

Sir , I’m looking for these three tubes , the rear , into the intake , front ..... you wouldn’t happen to have these for sale do you ? Michael

[@John87219]

Try RockAuto.com

[@mschiffel1]

Is it possible to convert a divorced choke QJ to a Hot Air model by switching the choke housing to the divorced model?

[@TylersNeighborhoodGarage]

Probably not, because the mount for the housing isn't there.

[@mschiffel1]

OK thanks...I just bought a freshly rebuilt QJ from Eckler's with an electric choke conversion...My current Edelbrock has a manual choke that I want to do away with...I've always had great luck with QJs.

[@CuringDaHOOD]

I have a 1984 P30 Chevy with 350. I am looking for the parts - the choke stove and the tubes running from the choke stove to the carb. Mine have rusted and appears the dealer says not available anymore. Help, thanks.

[@TylersNeighborhoodGarage]

I have to dig through the junkyard to find those now usually. I would suggest registering on a GM truck forum and posting a wanted ad for those items.

[@jeri8512]

What if I have fuel leaking from the choke and from the accelerator pump at the insulator gasket?

[@TylersNeighborhoodGarage]

You probably have dirt in the inlet needle.

[@jeri8512]

@@TylersNeighborhoodGarage alright I'll check thanks man.

[@DravenAutoDIY]

I have a 1981 Buick Electra Limited with an Oldsmobile 307 V8 engine, and a Rochester Quadrajet carburetor on it. I bought a new carburetor and installed it, but in the process the hot air choke tube snapped off at the plate that it goes into. I haven't risked removing the plate, for fear that the rusted bolts will break and something fall in, although now I see it isn't as much of a worry. Where could I buy another tubing setup for the air choke? I haven't found them anywhere.

[@TylersNeighborhoodGarage]

Sometimes you can find them on eBay, but most often you have to hit the junkyard. If the choke was working before, you can save some trouble and try removing the broken-off piece. Find a self tapping screw that grips the inside diameter of the tube good, thread it in and carefully attempt to pry it out or pull with a slide hammer. It should come out easily.

[@DravenAutoDIY]

Ok thanks. It was working mostly, although I think carbon has gotten clogged up in there and impedes it's heating abilities.

[@TylersNeighborhoodGarage]

TheDravenator It can't get carbon in it unless the tube gets a hole in it. It draws fresh air from a connection on the rear of the carb airhorn. It then travels through the tube as it leads from the carb through the choke stove and back up to the choke itself. What's likely is that the tube inside the manifold is rusting. When that happens the entire thing quits working because it can no longer draw a vacuum through the circuit.

[@DravenAutoDIY]

Ah ok, thanks. Yeah the choke was working iffy and I know what's above the engine is hugely rusted.

[@DravenAutoDIY]

WhoSaidTyler Although I am converting it to Electric Choke, the idea of keeping the Hot Air Choke is appealing and so I was wondering about removing the tube. If I were to try to remove it, and one of the bolts were to break (since they are so rusted), what would I have to do to cover the hole that would be left in there?

[@janman0405]

Hello Tyler, do you know where to get that particular hot air tubes, can't find them anywhere?

[@TylersNeighborhoodGarage]

I would look at Corvette restoration parts suppliers. Vettes used the same arrangement. If that fails, Quadrajet Parts may have them.

[@janman0405]

Thank you Tyler! I suppose converting to an electric choke might be best as the hot air tubes are almost non-existent?

[@TylersNeighborhoodGarage]

@@janman0405 probably so. They made versions of the Quadrajet that already have an electric choke as well. My '86 Chevy truck has one. Cars of that era normally had computer controlled Qjets but the trucks did not most of the time. if you want to be really swift you can route the power to the choke through a factory-style 3-pole oil pressure switch to keep the choke from opening if you sit with the key turned on without the engine running.

[@janman0405]

That’s a great idea, I’ll do that!

[@loganbyers996]

Do you know where to get sbc hot air tube?

[@TylersNeighborhoodGarage]

You can make them.

[@merlinglennon5370]

Do you want to sell the Dart😊

[@Ariccio123]

7:52 is the spider stock?

[@michaelszabo6410]

Alexander Riccio n

[@Robin_Gobblin]

Hi Tyler. I’m here with a question. I’m running a Pontiac Quadrajet on my 88 olds 307. In my 1980 C10. It’ll crank and run like butter. Even in the cold. I can jump in and drive anywhere I want to go turn it off and it will crank back up no problem. The problem I have encountered is after about 15 or 20 minutes of sitting after shut off when hot it spins and spins and spins but wont fire. Eventually with enough trying, it’ll fire up. Shut it off, fires right back up. Any help at all? Thanks

[@CT_Taylor]

spacer is common for heat soak

[@sgz1975]

I HAVE A LOT OF QUESTIONS I HAVE A 68' CAMARO WITH A 350 SB I AM A 3RD GEN OWNER WELL MY DAD LOST THE WHOLE CHOKE ASSEMBLY MY 1ST QUESTION IS WHERE DO U GET THE TUBING FOR THIS AM SORRY FOR THIS RIDICULOUS QUESTION BUT IF U DONT ASK U DONT KNOW THANK U 4 YOUR TIME I WILL HAVE MORE QUESTIONS BUT THIS 1 IS 1ST AND SORRY FOR THE CAPS JUST EASIER 2 C.LOL

[@TylersNeighborhoodGarage]

Try Quadrajetparts.com...also, since that's a Camaro there is a large aftermarket for them, so Year One and some other places have lots of parts for them and may have that tube.

[@sgz1975]

THANK YOU AND ALSO ARE THERE DIFFERENT CHOKE CONFIGURATIONS MEANING LIKE I SEE U R USING HOT AIR CHOKES WHAT ABOUT JUST THE ROD TYPE AM SORRY AM NOT SAYING THE CORRECT NAME I AM JUST BECOMING A MOTOR HEAD LOL

[@sgz1975]

IF U LOOK UP ON KZbin " ROCHESTER QUADRAJET 4MV CHOKE RODE ADJUSTMENT " U WILL C WHAT AM TALKING ABOUT IF U R CONFUSE BY MY COMMENT

[@SpencerBelanger207]

Mines sucking air out of the carburetor, must not be set ip correctly.

[@molo9256]

My intake dose not have that. What do I do?

[@molo9256]

Mine has no square for the tubes to ru down. What should I do?

[@TylersNeighborhoodGarage]

@@molo9256 If you have no provision for a heater choke tube then you'll have to find an intake that does have it or use a carburetor with an electric choke.

[@molo9256]

@@TylersNeighborhoodGarage okay thank you.

[@buggzo]

Looks like Oklahoma or Arkansas

[@TylersNeighborhoodGarage]

Worse...alabama

[@douglasgantt9548]

What to do if choke has robots instead of screws please?

[@TylersNeighborhoodGarage]

Rivets. Drill them out and replace with appropriately sized machine screws.

[@douglasgantt9548]

Tyler's Neighborhood Garage thank you. Will check the choke stove first.