84oldsDelta88

So i just got done rebuilding my carb that i picked up earlier and i've got a different problem now. When i start the car it runs for all of 2-5 seconds and dies unless i keep pumping the gas pedal. Choke is working and releases 1/8 of an inch about 2 seconds after car has started.

So what should i look for? I'm a little stumped, could it be the idle mixture screws need to be adjusted? They still have the tamper proof caps over them.

Thanks in advance for the help

BILL DEMMER

do you have the filter installed correctly?
is it loading-up? or stalling lean?
did you put the float needle pull-clip through any of the holes in the float?


bill

84oldsDelta88

I'll check the fuel filter in the morning.

I noticed that if i held the choke plate almost all the way closed (1/8-1/4 way open) it ran great. Which i think means lean correct?

Should i drill out the idle mixture screw tamper caps and try to adjust it a little richer?

84oldsDelta88

And not sure if its loading up or lean stalling. I'm assuming its lean stalling since it will just die out like it was starved for fuel

MDchanic

How did you rebuild it, and not remove the tamper caps and the mixture screws?

It sounds like you're not getting gas through the main jets.

Are you sure that you put the gaskets on the right way around?

- Eric

84oldsDelta88

Ok been up since the crack of dawn. Still cant figure this out. I tore the carb apart and checked and cleaned everything. All the passage ways are clear and i can blow air thru them. Its getting fuel as the carb bowl is full of gas and float is set at the correct level. Removed tamper caps, the idle mixture screws were at 5 turns which should be supplying plenty of fuel. I even tried taking them to 8 turns out and it still wont run on its own unless i hold the choke closed.

That seems to be the only way it'll run on its own is if i hold the choke partially closed (even on a hot engine.)

I'm running out of ideas on what to try next. any ideas guys?
I tried googling it but all that comes up is stuff about small engines like lawnmowers ect. ect.

84oldsDelta88

Well i didnt want to toy with them so i figured i would leave them where they were at.

I checked the jets and they're clear i was even able to blow air thru them so i dont think its clogged.

And i'm pretty sure the gaskets are on right I checked it when i had it apart this morning.

MDchanic

I only ask about the gaskets because I've done that one before, myself (though not on a Q-Jet). Took it apart at least 3 times before I finally saw that the gasket was backwards and blocking one passage.

- Eric

84oldsDelta88

Yeah that seems like something i'd do but checked everything and its all good. this carb is killing me. i've tried everything i could think of and still no go.

ThePackRat

It's a shame you couldn't get your hands on a carb that was known for a fact to be working/running well.

That would help rule out if you're doing something wrong.

84oldsDelta88

I have a total of 5 quadrajunks 2 cc versions, and 3 non-cc. 1 is off a olds 403, a chevy 350 and the last 1 which im trying to make work came off a olds 350
The 403 carb works but has a horrible off idle stumble which i couldnt fix, i think the carb is warped beyond repair i gave up hope on it.

The chevy 350 works but still had a little stumble and had no power, and the back barrels wouldn't open with this carb.

So far i've determined that the olds 350 carb is running too lean as if i choke the engine it runs great. but the idle mixture screw have almost no effect at enriching the mixture, not even the apt screw is enriching it enough

BILL DEMMER

did you compare the old gaskets to the new ones to make sure everything is identical?
did you disassemble the throttle body?


bill

84oldsDelta88

Yes i did, and everything lined up every hole was in the exact same place so gaskets should be good.

By throttle body do you mean the base plate that houses the idle mixture screws and the throttle plates? besides removing the idle mixture screws no i didnt disassemble it. Those throttle plate screws always break on me.

But on a positive note i did get it running it turned out to be clogged passageways a lot of flaky crap came out.
It idles good but once again I'm back to my off idle stumble issue. From a dead stop it hesitates slightly and becomes pretty shaky until the car gets moving.

And my idle mixture screws are pretty much ineffective unless their turned all the way in then the motor almost dies from lack of fuel. But no matter how many turns out it wont richen up the mixture.
And yet again my air/fuel ratio gauge is showing almost completely lean at idle.
I sprayed around the carb with carb cleaner and dont have any vacuum leaks neither

BILL DEMMER

yes, that is the throttle body, above it is the float bowl assembly, on top of the float bowl assembly is the air horn assembly.

it sounds like you still have some crud in the passages of the throttle body/float bowl assembly. you may wish to try a more aggressive cleaner. glad you're making progress though.


bill

84oldsDelta88

Ugh it never end I been at this for over a week now it seems every carb i have has some kind of problem no matter what i do. What would be more aggressive then carb cleaner? And thanks me 2 i just wish it would run right.

Guess im gonna tear the carb apart again for the 5th time today.

I'm really close to just saying the hell with it and driving the car into a tree.

henryk8398

Are you running a CCC Q-Jet? When I overhauled mine, I could barely get it to run at first. The odors from the exhaust plus burning eyes made me realize I was too rich. It turns out the rich stop for the M/C Solenoid was too far out. Since a CCC carb is full rich until the EMC goes into closed loop, full rich was too rich!

84oldsDelta88

Nope got rid of all the electronic garbage, was giving me too many problems all the time so I chucked it. I'm now running a late 70's m4mc carb and vacuum advance hei distributor.

J-(Chicago)

Hate to sound like a sheep or a lemming, but.....buy a holley and use that Qjunk for a door stop. After working with the new holly ultra HP I will never adjust another qjet again unless it's on a resto project.

84oldsDelta88

I would do that but im flat broke atm. have no credit cards to use. and i'd rather get this working right, at 1 point the other quadrajet i had was working great no problems and then out of no where it started thie off idle hesitation. Plus i already dropped what little money i had into these carbs i wanna make them work so i didnt just waste all my money for nothing.

BILL DEMMER

i guess i just don't understand what is the big deal. qj's are about the easiest 4-bbl. carb. to work on, if you understand them. if you try to cut corners, they can bite you in the butt, just like everything else.


bill

BILL DEMMER

carburetor and parts cleaner, comes in a gallon can at many auto parts stores.


bill

84oldsDelta88

I adjusted the idle mixture screws again, i'm now at a steady 19.5 in vacuum. but the screws are at 8 turns out just to get it there and according to my a/f gauge its still too lean.
But if i cover the carb most of the way and go look at the gauge its almost perfect in the ideal/rich zone.

I saw the carb dip at walmart today its b-12 chemtool brand will that be enough to dis lodge whatever is causing my problems?

84oldsDelta88

Just got done cleaning the carb yet again. I even used a can of seafoam afterwards, still no go still got the hesitation, what else can i do. There gotta be something i'm missing or not doing.

yankees

I've got a Holley 3310 for sale in the parts section. Pretty clean and has been stored away. Ran great on my old high 11's bracket car back in the early 90s

84oldsDelta88

Thanks but at the moment im flat broke and i already got so much time and money in the quadrajet that i'd rather just get it working right. I guess no one has anything else i can try or do to richen up the mixture and make it run right?

84oldsDelta88

So the weirdest thing happened today. The hesitation went away all on its own. I put about 60 miles on the car today so maybe that helped some. Mostly highway speeds 55 and up.

Well on my way home i looked down at my a/f ratio gauge and noticed that it was riding in the ideal/rich area (instead of lean like it had been). When accelerating from a light i noticed i had no hesitation and it had all its glorious power back. I even spun the tires accelerating from a dead stop cause i wasnt used to the power.

0-60 times are better, I'm doing 0-60 in roughly 7-8 seconds now. Not bad for a 4000lb boat with a stock 350 and 2.41 rear gears.

But thanks for all the help the past couple days. i can surely say i know a lot more about quadrajet carbs. from my experience.

BILL DEMMER

glad you finally got it, qj's aren't bad carbs. at all, you just gotta know what you're doing and be thorough(like most things in life).


bill

MDchanic

Nothing weird about it. That piece of crud that was blocking a passage, that you didn't remove any of those times you "cleaned" it, finally

• broke into pieces,
• dissolved,
• got blown through, or
• lodged somewhere out of the way (but may come back).

I'm glad it works now! As Bill said, QuadraJets aren't bad. Any carb can have a blockage from sitting idle.
They all work better when they're clean .

- Eric

L69

It magically cleaned itself out, no but really sometimes just driving these olds beast helps remove deposits of all kinds. Its worked for me many times and failed several other, but I wont mention at age 16 driving a 455 with 2 quarts of cheap oil would do. That was many many years ago.

84oldsDelta88

This morning was the ultimate test. Took it out for a spin and it runs great, I do notice a slight hesitation on a cold engine but once it warms up to operating temp. hesitation goes away. Probably a choke adjustment needed. All in all I'm happy, and I didn't have to buy an edelbrock or holley

The car has so much pick up compared to before when i was running the computer controlled set up. Anything more then 1/4 throttle spins the tires from a dead stop. Hell i can even spin the tires from a 10mph roll . Although I do notice some pinging upon acceleration, I think the replacement vac. advance i got from advance auto gives too much advance. Now I just need to hit up the drag strip and see what my 1/4 mile time is.

Also i think i got the carb adjustments dead on. My air/fuel ratio gauge is riding in the middle of the ideal zone . My current adjustments are APT screw is 3.75 turns from seated, and idle mixture screws are at 8.25 turns, 73 jets with 55 rods cv secondary rods with H hanger.
The pics are of the carb from the JY before rebuild (wish i would of taken a pic before i scrapped all the crusty crap out. you can see some of the corrosion on the secondary rods.

MDchanic

That's normal for a carbureted engine with the choke on.

- Eric

J-(Chicago)

Nice job, and I commend you for sticking with it.
I used to do the same thing years ago, but the juice just isn't worth the squeeze anymore.

CV are good rods. I have a Cigar box full of Qjet rods if you feel you need to adjust it further.

84oldsDelta88

Well guys just an update to the problems i been having with off idle stumble/hesitation/misfire. Its finally fixed!!!

It wasnt carb problems, it was ignition. I took the car to a garage i used to work at. And had my ex-boss take a look at it, within 2 minutes he knew it wasnt carb problems but ignition he said it was a misfire.

So first i tried new plug wires which made a little difference but still would have the hesitation on off idle acceleration just randomly now.

So today i decided i'd pull the spark plugs and check condition and gap. I regapped the plugs to .045 (it was 0.65 originally. All the plugs looked good except number 8 (pic below). It was in horrible condition looks like carbon build up or even oil fouled. Went to the store bought a new ac delco r46sz regapped at 0.45 and the car runs amazing again.

I'm guessing the valve seals in cylinder #8 are done. Or my piston rings are shot and letting oil by.

The funny thing is those plugs only have roughly 10,000 miles on them.

MDchanic

I'm very glad you found the problem and got it running well!

The above is a far cry from this, though:
The problem that you found should not have been causing the problem you described at the outset.

That plug is icky, though.

- Eric

84oldsDelta88

Thanks i'm glad too. I went through hell the past couple weeks but am happy that its back to normal again. Although I think i'm gonna do a compression check to see how far off cylinder 8 is and if its good then i guess i'll be pulling the heads to replace valve seals. The guys at the auto store said it looks oil fouled.

What do you mean (The above is a far cry from this, though)? is that gap too small? should i go back up to 0.60-0.65? The engine seemed to run great at 0.65 from December til July. Everything was good til I switch to non computer carb and dist.

I know the problem in the first post wasn't cause of the spark plug. That problem was the carb clogged up with crap, once I thoroughly cleaned it, it ran good but still had the off idle stumble and hesitation. Which was later diagnosed as an ignition misfire by my mechanic ex-boss.

MDchanic

No need to pull the heads to replace valve guide seals. It's a bit tedious, but not a hard job.

And right they are.

I mean this:

The exact gap isn't super important in this case -
You've got HEI, so in theory you can run a 0.065" gap, but in practice such a large gap isn't necessary, and running it puts an added strain on the insulation of your ignition components.
The engine was designed to run at 0.035", and so 0.035" should be fine.
If you wanted to go up to 0.045", that'd be okay, too, but you probably won't see any advantages above that.

I would say that now that you know that you've got oil in that cylinder, and that it fouls out at 10,000 miles, you should probably make a point of checking that plug every 5,000 miles or so, and cleaning or replacing it if necessary.

- Eric

84oldsDelta88

Really? Wow so how do you replace them without removing the head I'm curious now?

Oooo right gotcha

Yeah i guess every 2nd oil change i'll pop out number 8 and check it until i can afford to do valve seals.

I cant believe i spent all this time and money tearing down and playing with the 3 carbs i got, to find out it was a fouled spark plug in the end. I never checked them cause the passenger side is a PITA and i kept telling myself "Oh their good they only got 10k on them it cant be the spark plugs" aka lazy. Leason learned.

SBORule

Go back to the shop where you use to work and maybe your old boss will have everything you need to replace the valve seals, it's not hard but it isn't easy either.