How to rebuild a Rochestor Quadrajet part 1

[@MedicJoeJoe]

Thanks to you just rebuilt my carb on my 66 el camino. Just layed a nice patch of rubber on the road! I had that piece you talked about that prevented the secondaries from opening if the choke wasnt adjusted right. Threw it away and I truly believe that it was limiting me from the secondaries because it has never run this fast before. Thank you for the very detailed videos couldnt have done it without you.

[@loniedavis1167]

JUST WANTED YOU TO KNOW YOU DID A REAL GOOD VIDEO ! I WAS A OLD MECHANIC BACK IN THE DAY ! I HAD FORGOT SOME OF THE STEPS AND YOUR VIDEO WILL MAKE THIS REPAIR MORE CORRECT ! OH AS IT WOULD HAPPEN I AM WORKING ON A 1986 DODGE POWER RAM [W-250] 4X4 ! THANK YOU YOUNG MAN !

[@TylersNeighborhoodGarage]

+LONIE DAVIS Thanks!

[@jimlindsay9658]

+WhoSaidTyler HELP!!! I have watched your video 3 time and they are great but I cannot find my problem. My Quadrajet is a marine carb. I have let it soak is carb cleaner 3 days and taken a air hose and blew everywhere. I have put a new kit in it and a new float. I checked the float and it is shutting the fuel off by blowing in it and manual moving the float until it quits. It is dumping gas into the oil like a quart or more in three min. New nettle and seat and the clip is not in the little holes in the float. The power valve was originally stuck and I cleaned it with 00 brass wool and oiled it and it manually works great. What makes the power valve work... vacuum? What do I need to look for? Thanks Jim Lindsay [e-mail]

[@TishFire312]

Tyler, I just want to thank you very much. You've taught me a lot about the Q-Jet and I walked step by step with you rebuilding mine using this video. I'm glad you're putting these videos out and I hope you put out many more...Subscribed!!! Wish I lived down in SE HSV to help you rebuild those others in your back yard...

[@Careica]

Yeah, been looking forward to see you making a video about rebuilding Quadrajet! Mine is fine on my '83 Caprice since its running well and pretty good on gas, but I will surely rebuild it or get a spare and rebuild it some day. Your videos are always informative yet entertaining to watch too! Thank you!

[@theoriginalehombre]

Thank you very much for posting this series of videos. I rebuilt the carb for our 67 Pontiac. It runs noticeably better and no longer leaks gas. Have a great day/year!

[@davidcrichton-gill754]

Thanks for the video.....if I hadn't watched it I wouldn't have known where that choke lever went, the one that comes up through the body, and the tape idea worked a treat. Also I had the needle valve spring hooked up,wrong, I put it through the hole!! I thought there might have been a new seal for the power piston in the kit Thanks mate.

[@TylersNeighborhoodGarage]

David Crichton-Gill You are welcome.

[@glennquagmire835]

Hey Tyler, great video series on the Q-jet. I learned a lot about it and you took the mystique out of it for me. I've got one on an old boat I bought last year (Chris Craft with chevy 4.3L) that was kind of sickly. I couldn't get it to fire up and after watching your video I found one of the suction tubes had fallen out and the float needle had been clipped into the hole of the float bracket. Then I get it to idle (would only run if I feathered the throttle and it would surge to 5200 rpm or die out) and found the air/fuel mixture needles were backed out 4-1/4 turns. I haven't tried it yet but I've set them (now) to 1-1/2 turns out. Oh, and the automatic (heat choke) was just dangling from the linkage (not bolted to the intake manifold) which had the connecting link installed backwards. I think I have it figured out now but need a day off to put it in the water to see if I have it close. Again, thanks for the video and great information. (Quadrajet #17084516)

[@TylersNeighborhoodGarage]

Thanks man. You found a lot wrong, I'm glad it worked out for you.

[@k5ren]

Hey Tyler, I just wanted to thank you for several things. I recently bought an old '71 LeMans Sport with the 400/400 drivetrain. I'm taking the 2GV carb of and installing a 4bbl intake and Q-Jet which will need a rebuild. I have years of experience with Holley carbs and have always preferred them over anything else. Well now I'm poor and was handed a decent Q-J core. First thing that came to mind is ALL that negative input I've heard over the years and my own experiences with them, adjusting and "mods" taught by 'others' with extremely shitty results. But being poor, I guess I'll HAVE to use this thing huh? Damn. Well then, in search of some REAL knowledge on the Q-J, I watched several videos and happened upon your many additions to the world wide web. I watched one explaining the differences between Holley and the Q-Jet and I could seriously appreciate the safety factor of both the accel pump being enclosed and that the gas can't leak from the bowl like I've experienced many times with the Holleys. That and the fact that I myself have been talking trash about them for years. You pretty much sold me right there in that video, I quickly (and openmindedly) realized that maybe I was the problem, maybe I just need a little education on them. (Thank you.) I've yet to tear into the Pontiac project but it's coming soon. Meanwhile, my sister's '70 C10 Q-J developed an issue with being far to rich and hard starting overnight leaving her stranded. I was able to make several adjustments to the choke and idle circuits to enable her driving it again, not perfect but dying anymore. It's her only ride. This weekend I rebuilt her Q-J and stayed close to the GM manual, a Q-Jet book, but mostly, your video series on the rebuild. I went forward with much confidence this time! I do have to say, and you know some think you talk on too much, and I've been frustrated at times with you too, but THAT'S on me and my impatience, and when I took the time and listened to what you were saying inbetween and during procedures, I found it was very pertinent advice and shared experience I couldn't find from Joe Dirt up the street. Not all of it but quite enough! I had tremendous success as it fired right up with minimal adjustments. This morning's cold start was quick as it should be except she stalled it in reverse. That's probably just one of those girl things, stalling vehicles, you know.... So thank you Tyler, for changing my attitude towards the Rochester Quadrajet, dispelling many myths I've held onto for decades and arming me with good knowledge to understand and even defend the mighty 4MV! All this info coming from a Mopar man like myself too! Keep jabberin' - I jabber too. You're alright!

[@TylersNeighborhoodGarage]

Hey man, thank you for the nice comments. There are things I could have done differently as far as video production goes, but we are all learning.

[@k5ren]

It's called experience. Let's keep getting us some!

[@austinmitchell331]

Hey man, great video, thank you very much for posting. I am just about to do a rebuild on my QJ for my 87 Ram, this video is gold for me! Thank you!

[@hound4u937]

Thanks. I was turning each mixture screw to see if the engine would still run and I also had a vaacum gauge connected too to help set the carb up. I kept turning the mixture screw expecting it to eventually stop.

[@JoeNusz]

Of course you post this literally two weeks after I rebuild the one on my 350 Chevy. I did learn about the heat riser choke from you though - and that the QuadraJet can do more than suck! If you don't mind me asking, after rebuilding it sounds like the engine is going to die after I give it a little gas to take off from a stop. If I tap the gas, let it hesitate, and then give it gas it is fine. This seemed to mostly happen during humid weather. Any ideas appreciated!

[@bobbynip66]

Your video's are really informative! Thanks for posting them! The reason I'm looking through them is.....when driving, everything performs well, no bogging or hesitation. I can shut the car off, and crank it back up immediately, and it cranks with no problem. I can also let it sit for much longer (like an hour), and it fires back up with no problem...but...when I shut it off, and it sits for about 10 minutes, it won't fire. I have to be careful not to wear the battery down trying to start it and just let it sit. Usually about a half hour and it will start right up. Would you have any guesses as to what's going on? Thanks!

[@TylersNeighborhoodGarage]

Try never to make guesses. Problems like these can be diagnosed by simply thinking of the 3 things an engine needs to run, at the right time and in the right amount: 1. Fuel 2. Air 3. Spark. What is happening in the space of 10 minutes to cause a no-start? The first thing I consider is heat soak. When you turn the engine off, the temp goes up 30 degrees or so for a little while, then cools down. So, likely that either the fuel is boiling(vapor lock) or the ignition system is conking out. My instinct tells me vapor lock since there don't seem to be other running issues mentioned. I suggest buying a spark tester, and then try to create the situation where the engine will not start. When that happens, pull a plug wire, pop the spark tester in place and spin the engine. If you see results in the spark tester then you know your issue is fuel related, and not ignition. After that you can evaluate the carb to determine whether the problem is flooding, or vapor lock as I said. Now you can DIAGNOSE and not guess :-)

[@bobbynip66]

WhoSaidTyler Thanks a lot! I'm starting to DIAGNOSE it now. I will get a spark tester and eliminate that as a possible problem, and move on from there.

[@TylersNeighborhoodGarage]

It is flooding. There is a needle valve inside the carb which is closed by the float when the fuel level rises high enough. Think of how a toilet works. Sometimes the little rubber-tipped needle gets trash on it and doesn't shut off all the way, or else the float has started taking on fuel and sinking. Either way you will need to pull off the airhorn so you can check those items out.

[@ryanmiller8741]

Hi there. I followed your videos on rebuilding my quadrajet 4 barrel carburetor and I believe I successfully rebuilt it thanks to your videos! However now my choke don't wanna open up. And my vacuum brake I believe Is good. When I manually open the choke the engine dies out. Also engine is hard to start after warmed up. However starts up good cold.?? Any tips? Thank yoy

[@doctruptwn]

God it's been forever since I had one of those apart.

[@TheProfessor936]

Im rebuilding a quadrajet. After i dip in berrymans for a day, do I follow up with berrymans ez doz it to orevent flash rust, or do i not have to worry about it. I figure the oils would hurt the integrity of the seal

[@MrSwascott1981]

OK thanks a lot I'll check it out tomorrow and I'll post my findings

[@RoadRacerGT]

Tyler, I am rebuilding 2 quadrajets, a 77 Olds and a 75-76 Olds. The older unit has the adjustable "filler spool" and the secondary power piston with single rod. The secondary power piston appears to have the same size spring. Should I retain this power piston? or should I jb weld the jet and toss it?

[@frankburnsjr]

What'd you do to lubricate that shaft (don't know the name of what it was connected to, but it was on the airhorn) so that the "plate" would close? You were talking about it toward the end of part 11. Also, other than spraying with brake cleaner and soaking in carburetor cleaner, did you do anything else to clean it up? Thanks.

[@carbpumper]

a couple weeks ago i rebuilt my quadrajet on my Dodge 360......small world

[@billbrown7519]

I took the carb apart again and went through every hole and could not find any blockage. Could it be a weak fuel pump? Ps it had been 3 years since it ran last. Had a lot of water and gunk in the lines, tank and carb. Just bought the boat.

[@larryp6814]

New to quadrajets, new to v8’s. I’ve tore down a 17058507 using your videos. Vehicle is a 1978 El Camino with an a/t. 3 questions: 1) 1 of the locating pin broken from center piece any reason to try to drill carb body to replace? 2) my carb does not have a removable air horn baffle but there looks like a baffle in the air horn throat is this the same thing? 3) Upon disassembly there is a piece of foam like material in the lodged in the fuel well below the plugs that are usually epoxied. I can’t find this on any parts list or rebuild video, ideas?? Thanks for your time...

[@larryp6814]

By the way I enjoy the detail of your videos so talk away😁

[@beegeewhy]

7040244 .....1970 Buick GS 350 I've just read that some folks actually do away with the secondary pulloff.....I'm with you though tyler...I wanna put it back the way Buick designed it... Thanks Tyler!!!

[@TheSirjohn2012]

It too bad that after the 1990 year the q jet carbs,and other types are no longer made. However although I may be wrong I still prefer these over the other types I practiced taking apart over a period of time. The holleys have one edge over the GM carbs and that is you can make adjustments,while the carb is bolted on the intake manifold,i.e. float adjustments etc.

[@707SonomaComa]

What would be different on a 1969 Chevy C-20 350? It has an automatic trans. and a module where wires plug into on the rear of the carb on the driver's side. What rebuild kit would you recommend?

[@GarbageDanks]

Where does the vacuum line from the vacuum break go to? Is it the egr solenoid?

[@MedicJoeJoe]

I just gave mine a thorough wipe down and went on my way if you leave it out to dry for a good period of time it evaporates right off the metal. mine did not appear to rust after words.

[@jgorney1231]

Quick question. This seems the place to ask and get a correct answer. I've got a 1990 omc cobra 5.7. Has a 4bbl quadrajet. It bogged down on full throttle. Would take off and then fall on its face. Everything looks together from watching your videos. My question is should all four barrels open up with a snap throttle?

[@TylersNeighborhoodGarage]

All four bottom throttle blades should open fully at full throttle. The large rear air doors up top are vacuum/airflow dependent, and open proportionate to the engine speed and amount of air being ingested. However, I suspect your issue is that one or more of the secondary pickup tubes that press into the airhorn have fallen out or less likely, the plastic cam that lifts the secondary rod holder when the air doors back there open is broken. When either of those happen, you get a huge stumble and bog whenever the back barrels try to come on because there's not enough fuel to match the air through the secondaries. You can easily observe the plastic cam condition by poking the air doors open with your finger(engine off) and watching whether the small metal lever in between the two large air doors lifts. If not, you can replace the cam itself with some effort. If it does, then you move on to check the pickup(actually called pullover enrichment) tubes You can check and repair the tubes by disconnecting the accelerator pump rod and then carefully removing the airhorn(top of the carb) after removing the screws. Remember that there are two screws inside the primary bores. When you pull the airhorn you will likely see one or two small tubes laying loose inside the carb back there. You can carefully push and then gently tap the tubes back into place and reassemble. Good Luck.

[@beegeewhy]

Tyler help PLEASE!! I've bought Cliff Ruggles book, searched the web, and still can't find out how my QJets choke should be set up. There's a primary pulloff, a secondary P.O.on there...and, I THINK....there's supposed to be a bi-metal T'stat, correct? How does the spring (T'stat) linkage attach to the carb???????? How do these components work together?

[@TheMowerdude]

tyler do you know what would be wrong with my 78 k20 350 it likes to "chug" for lack of better terms until you have the throttle halfway down

[@nathanpeytonsharers2789]

Just finished my rebuild and when I first turned the engine over it was pumping fuel up through the middle???? Any thought????

[@jhudsonjr80]

Im having a problem with my Quadrajet is not using down on its own. I have to manually press the linkage down in order for it to idle properly. Sometimes when I shut it off my car diesels. Can't figure it out. PLEASE HELP!

[@rickyochoa6785]

hey Tyler I have a 1976 Camaro with a Rochester quadrajet and fuel stars to come out off the carburetor and then it chokes on it and it ends up turning off if you could help me I would really appreciate it.

[@MrSwascott1981]

I've got a question why would the gas spit out of the top in front of the choke plate

[@paulfraley5148]

Rebuild my quadrajet following your videos. Installed it, everything ran good, then it started leaking then pouring gas around the accelerator pump...any ideas? Thanks

[@TylersNeighborhoodGarage]

You have trash in the needle and seat, or the float is sticking for some reason. Time to pull the top off and investigate. Make SURE you are running a good filter and if you suspect there's trash being pulled from the tank, run two temporarily. The needle valve hangs off the edge of the float, it does NOT hook through one of the small holes there.

[@powergolem89]

hey tyler. i was wondering if you could use this same rebuild on a quadrajet with a divorced choke?

[@TylersNeighborhoodGarage]

Sure, just a bit different linkage there on the right side.

[@hound4u937]

Hi again. I broke the passenger side air fuel mixture adjustment screw off! Any suggestions? I was closing both screws to see if the engine would die ( it kept running) so im guessing i have a vaccum leak. SBC running way too hot as well.

[@TylersNeighborhoodGarage]

You'll have to see if you can use a small ez out to remove the remains of the screw. Don't turn it in so hard! Just lightly seat them or it puts a mark on the tip of the mixture screw. You should check the base timing...sometimes that will keep the carb from reacting to adjustments.

[@SmokinRcVA]

Well i have just rebuilt my quadrajet. And i have 1 left over part. Not sure where it goes hoping you could maybe help me identify it so i can figure out where it goes. So if it possible i would like to email you a picture of the part.

[@TylersNeighborhoodGarage]

r3dnkn I PM'ed you my email.

[@TylersNeighborhoodGarage]

Can you get me the number off the carb? It's on the left rear side, running vertically.

[@TylersNeighborhoodGarage]

Yes. I don't at the table. I eat in front of the TV or Computer :-)

[@carbpumper]

@carbpumper my truck had the fuel filter in the carburetor like yours

[@coltingleave6934]

I rebuilt my quadrajet now when I punch the accelerator the secondary plates are sticking

[@TylersNeighborhoodGarage]

The fuel level is too high in the float bowl, either because of dirt in the needle valve or something wrong with the float itself.

[@jdreneau744]

So I'm having a problem with my Quadra jet ... it's in a 85 chevy van. It will idle it will rev it will idle in gear but as soon as I give gas it chokes out n dies at this point will not start unless I'm standing on it to the wood. It starts and barely runs keeping foot to the floor and it's just puff puff puff dies... when it does this I can go away and come back a few hours later fires rt up same thing tho.... the secondary is being sucked closed by vac break I think but it's closed and if I open it like the primary it will run in gear and rev up and drive o on as I take finger out of butterfly it closes and dies ...same scenario.... what do I do what could it be???? I'm on a disability income so low budgets my thing rt now lol any advice would be appreciated

[@TylersNeighborhoodGarage]

Make sure the bottom flaps at the rear(secondaries) aren't stuck open. Sometimes they can stick if they haven't been used much. Otherwise, it sounds as if the carb is trashed up and flooding. Bottom line is it needs cleaned and rebuilt. Good luck.

[@jdreneau744]

How would I go about in sticking them.. the van sat for few years...

[@jdreneau744]

Un sticking srry

[@TylersNeighborhoodGarage]

Jesse Reneau The lever is at the driver-side, near the rear. If you look at it, you'll see how the linkage pushes rearward when you open the throttle. You can take a flashlight and look down the back barrels also. That may not be your problem, but it's worth a look. The "sat for a few years" reinforces that the carb probably needs gone through. Today's gas turns to varnish MUCH more quickly now.

[@jdreneau744]

Thank you very much I been trying to figure it out asking ppl but not to many ppl I've found who know anything about Quadra jets... Ty may I hit u up again if I need an answer or two lol

[@meatdogg101]

it's all good though,just kidding.Good work on that carb

[@larryp6814]

This video is 8 years old, is it too late to ask a question?? (Love the video series by the way).

[@TylersNeighborhoodGarage]

Not at all. What's up?

[@TylersNeighborhoodGarage]

@carbpumper that's unusual that they used 2 filters...

[@bigjay_yt8183]

why would you use a 3 year only one? now we gotta guess if ours has the same components?

[@TylersNeighborhoodGarage]

There's very little difference between the components of any given Quadrajet. Mostly it amounts to changes in the way the linkages connect, 750 or 800 cfm, and metering circuits that are not easily or needed to be altered by a home rebuilder.

[@billbrown7519]

I just finished rebuilding my marine quadrajet carb. it starts and runs as long as i rev it. once I hold the throttle still it dies. Any idea why?

[@TylersNeighborhoodGarage]

It's running off the accelerator pump shot. You appear to have a blockage in the main circuit. Clean, clean clean, and blow each and every passageway out with compressed air.

[@billbrown7519]

I blew out every hole, even used a WD4 can and blew though every hole and all were open. I have had this apart 4 times now and it does the same thing every time I put it back on. The motor runs if I rev it and dies as soon as i hold the throttle still. I can see gas shooting in when I pump it. Could it be the fuel pump? This is kind of a dumb question but is the gas sucked in by the vacuum of the motor or is it pushed in by the fuel pump?

[@billbrown7519]

I learned if i partially close the butterfly it runs fine, It is like it does not have enough vacuum to pull the fuel through.

[@TylersNeighborhoodGarage]

Bill Brown Vacuum isn't the issue, because in order to "lose" that much vacuum you would have to be experiencing severe mechanical problems. You gave an essential clue: It runs better with the choke partially closed. That is a tip-off that the carb has a fuel restriction somewhere. My guess is that one "side" of the carb is dead because of something stuck in the passages. Qjets have air bleed circuits that also have to be open. My suggestion is to get a "cutaway view" of a quadrajet so that you can see the path the fuel follows starting at the main jets and then start looking for a blockage or restriction. My own carb was plugged in the passage that leads from below the main jet to the venturi nozzle, The only way i found it was to spray spray until I could discern a difference. I wouldn't beat your head against the wall endlessly on this. Carbs do NOT recover well after getting water in them, if that indeed happened, so you may be better off looking on eBay for a similar carb and using that after a rebuild.

[@jcfox2645]

Ok I've taken the quadrajet off my truck and put an edelbrock cause I don't know much about carburetors and the needle messed up but I wish I'd found this so I coulda tried fixing it. Anyone want to rebuild mine or able to teach me hands on so I can?

[@jerrya27]

where do u buy the kits ?

[@TylersNeighborhoodGarage]

Any chain auto parts store should have them. Be sure to have the carb # with you.

[@jerrya27]

ok thanks i tried the auto joke here they dont carry them guess ill try car quest

[@TylersNeighborhoodGarage]

jerrya27 What carb # are we dealing with?

[@jerrya27]

i found the kit at car quest ..the carb had been sitting on a blown motor under the roof line catching water for a year ...put it on fired right up.quadrajunk my ass haven't even rebuilt it yet

[@meatdogg101]

on the dinner table though????

[@richardmaaske7483]

Before you started to work on the carburetor. You should of , turned it upside down. Let gas run out of fuel bowel.

[@fposada413]

is there a way to unclog the prime jet on a qudra-jet

[@TylersNeighborhoodGarage]

+Jose Posada not externally