defiant1

Okay party people, this is a new one for me. I drove 10 miles and had 8 ounces of gas sitting on the intake manifold (drivers side). I took off the air cleaner and saw gas puddled around base of the accelerator pump shaft/hole.

So, I assume it is a float issue. i.e. the float was set to high, float assembled wrong (clip in wrong location), bent float arms, etc.

Any thoughts or practical experience on what I should be looking for when I tear this thing apart?

BTW, other than the puddle of gas filling the voids of the intake manifold the engine ran fine.

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MDchanic

It does sound like your float level is too high.
The first thing I would do is to mop up all that gas, then get the engine nice and warm and run it without the air cleaner and just watch it. The fuel pump should be pumping a lot more fuel at idle than the engine needs, so it should be able to make the problem very apparent.
Once you can see where the fuel is coming from, you can take the next step, which will probably be to remove the air horn and examine the float, pivot, needle, and seat.
In addition to crud between the needle and seat, a pivot problem, or the float having mysteriously taken on a new adjustment, the float may have absorbed gas and gotten heavy.

- Eric

Koda

Did you tighten down the bolts to the intake?

TripDeuces

Did this happen all of a sudden? Because that would make no sense. Do you know what your fuel pressure is?

defiant1

It did not do it when it was at idle. I know this as I was fighting with adjusting the fast idle and timing a multitude of times and did not have any issues. It only seems to have done it at highway speed/under acceleration. I will double check at idle though.

It seems like it happend all of the sudden. Although I have not been able to drive the car more than a couple of miles since installing the carburetor. If I hadn't have smelled the gas this morning while driving I would have probably leaked out a half gallon before I reached my destination.
I don't have a fuel pressure gage with this set up, but with the Holley setup I had on there before this Qjet, I was gettng 6-6.5 psi for a reading.

TripDeuces

Well the QJet is more than capable of handling 6-6.5 psi so you're ok there. Time to check the float I guess.

Fun71

So it's a new carb installation. I once had an issue after removing the fuel line with a tiny bit of crud (speck of rust or dirt?) getting stuck on the needle valve and keeping it from sealing with the seat.

defiant1

Finally had a chance to tear into it. The float checks out and no contaminants were visible in the needle seat.

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MDchanic

Even though you didn't see anything, it is still possible that a tiny particle was hiding in there.

You may have just fixed it without even realizing it.

- Eric

anthonyc

The cup on the accelerator pump can dry out too. Some of the cups are not compatible with ethanol. This would let fuel get past the cup and onto the top of the carb. Ive had to replace mine a few times. Now I got an ethanol compatible one in there. Seems good. Sounds like too much gas for that though. But keep it in mind.

brown7373

If the tip of the needle is bad it will not seal to the seat and let fuel flow freely into the bowl. Too high a fuel level from a leaking needle & seat will come right out the pump shaft.

pogo69

There are also some well plugs on the front that can leak ubder pressure but you would probably notice that

defiant1

I thought the same thing, I assembled the carb put it back on and the same result.

I agree, all the parts in the carb are new. The cup is the blue one and it is pliable and contacts the wall well. I could try another one though and see it if changes anything...

I vacuum tested the needle to the seat and it held vacuum like it should. I filled the bowl full of gas and the needle did not leak anything out the fuel inlet (carb off vehicle). So, I think the needle is good to go.

Well plugs are sealed off.

________________
So, not sure what else to try. The only thing I haven't verified is the fuel pressure (as TripDeuces alluded to), but not sure how that could magically increase all on its own...

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TripDeuces

This is the original carb for the 70 pictured?
Only other way fuel can enter the bowl, assuming this is a 70 model carb, is if the seat portion of the needle and seat isn't tightened sufficiently in the carb body or there is a crack somewhere. Was there a gasket between the seat and the carb body? Also is the float damaged so that it is soaking up fuel and sinking rather than floating? Can always switch to a brass float if need be. The foam floats can be prone to damage to the outer skin (from say dropping it) and this allows fuel to soak into them.

defiant1

The carb is a 7042250 (1972) vs. the original 7042050 (1970). I tested the needle and seat and it works like it should. Gasket is in place. The float did not seem damaged or gas logged. I compared it to others I had on hand and no discernable difference. Plus when I filled the fuel bowl (with the air horn removed) it had the buoyancy required to seat the needle.
I am perplexed to say the least...

defiant1

Well I am having no luck at all figuring out this carb.

I installed a new float, plunger, needle and seat and a new air horn gasket. I adjusted the float an 1/8" lower than what the manual calls for.

It is still overflowing gas through the airhorn gasket and accelerator pump plunger. Not as much as before, but still leaving puddles of gas on my intake manifold.

Other than fuel pressure being too high, what else is there?

Is there a way to reduce the fuel pressure? All I have is a mechanical fuel pump pushing gas through the factory fuel line to the carb.

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TripDeuces

This same sort of thing happened on my 66 QJet. They are a different animal than the later carbs and have another tower type arrangement next to the needle and seat that isn't used and was plugged from the factory. Unfortunately that was right where it was leaking additional fuel into the bowl from.
I doubt you have this earlier type carb so only two things come to mind, a crack or cross threaded needle and seat or the top plate is warped from someone torqueing the life out of the front bolts.

defiant1

The pin that holds the float arm in place, is that supposed to be held down by the air horn/top plate? The C-shaped pin is not secured and just rests in the slot provided. So I am thinking as the fuel fills up the bowl the float raises due to buoyancy since the pin isn't held down by anything it allows the needle to come unseated allowing fuel to continue to fill the bowl.

Koda

Try disconnecting accel pump lever or linkage and go for a short drive. It will bog if you hammer it, so don't. The idea is to see if accel pump is doing this or if it's increased fuel pump pressure from high RPM or something else. Your accel pump lever pin might be peened in some, so don't break anything and stop if it won't work.

MDchanic

Have you tried a different float?

Technically, the float has a specified weight, and if it's heavier, it's no good, but your symptoms would be explained by a heavy float.

Your description of the float pivot pin sitting loose in the groove sounds like the normal way it's supposed to be.

- Eric

TripDeuces

The C shaped clip you mentioned (float pivot pin) sits vertically in the slot provided and yes the carb top plate holds that in along with everything else.

http://www.vetteprojects.com/kstyer/quadrajet_4.htm

Have you put a straight edge against the top plate right over the bolt holes?

Koda

Oh, duh. Why didn't I think of this before? Before you go disconnecting that accel pump, take the air horn off and squirt some carb cleaner down its passage. I bet your checkball for the accel pump circuit is stuck open, and when you hit the accel pump, it's sucking it back out and puking all over your manifold instead of closing the check ball.

defiant1

I used a new float. I could not find a different sized float that had the same arm dimensions so it would install correctly. There is a brass float I could use I guess...

I have not. I need to know where to put the straight edge. Is it over the center of the air horn or over the bolt holes (front to back or side to side)?


I installed a new check ball. Can the screw that sits over the check ball affect it any?
________________________
I did one last try tonight with no better results. It does sound like it is sucking air, so it could be a warped air horn. I hate this carburetor...

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defiant1

So I send a message to the seller of the carb (carbdoctor from ebay), this is his response:

"As your describing, and what you have already done, the flooding is not a carburetor related problem. I checked with my Olds guys and they seem to think the ignition or cam timing is retarded. (Bad chain or jumped tooth) This would cause reversion thru the carb forcing fuel out of the top. Evidence of this was also on the base gasket. All Olds carbs are warped. The top gasket is thicker and you will see impression marks where in contacts the body. Lowering the float level will only worsen the problem. "


- carbdoctor

With cam timing being off, I've seen gas being forced out of the carb just by cranking and not running. I think it would be a good idea to check compression.


- carbdoctor

Anyone have any advice based on his response. I have never heard of reversion on a carb before, so I have no frame of reference.

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Octania

Mmmmm, that is some Grade-A Bullshed right there.

"All Olds carbs are warped" - you don't say?

brown7373

Before you installed the new check ball, did you use the old one and give if a sharp rap to ensure it has a good seat? I use a nut driver without a socket to tap the ball, then throw it away and install the new one. Just be gentle, you aren't driving a 20 penny nail into the porch.

TripDeuces

Complete and utter bs. With a retarded cam or timing there is even less chance of reversion because the intake valve is closed. Reversion are pulses back up through the intake tract. This guy is feeding you a line.
"All Olds carbs are warped" More bs. They don't come that way from the factory!
Messing with the float level anyplace other than the mandated setting is not advised. It only effects the level of fuel in the bowl. Having it too high will cause fuel to leak out the top but you lowered it and still had the problem. Lower it too much and you run the risk of running the bowl dry POSSIBLY at WOT. Carbs don't run on fuel pressure they use atmospheric pressure pushing on the fuel in the bowl to supply fuel. As long as the fuel pump is supplying enough fuel to keep the level of the fuel above the jets and covered it will run just fine. This also assumes the jets don't get uncovered under hard acceleration.

Another thing you could do is empty the fuel bowl and pressurize the inlet with air. Hold your finger on the needle and float and listen for air entering. I'm convinced you have a leak somewhere. There's a reason the fuel is coming up so high in the bowl. You need to find out what that is. Even if fuel got on top of the accelerator pump plunger it just bleeds off into the bowl through a slot. It's not like it's under pressure and being forced out through the top of the carb.

Things I'd check:
1) Needle and seat installed incorrect. Whether that's cross threaded, spring clip on needle in wrong position, bad needle or seat, missing gasket, etc.
2) Crack in carb body bypassing needle and seat, not governed
3) Excess fuel pressure. I think you checked this

pogo69

Did you reinstall the metal gasket under the needle/seat

defiant1

Yes, I completed this procedure.


I have done #1. I will examine the carb body further looking for cracks. I guess I can hook up the holley fuel lines with the fuel pressure gauge attached to double check the pressure again. Pressurizing the fuel bowl is a good idea too.

Yes, gasket was installed.

_____________________

Thanks for everyone's advice.

d1

pogo69

I would just file this carb int the 'wtf' drawer and just get another carb

MDchanic

Wow. That was one tri-axle load of BS right there.

After a response like that, I would check the carb very carefully, as you now know it has been through the hands of a scam artist.

My personal recommendation is to do a full-on test in situ.
Pull the air horn and all the spark plugs.
Disconnect the coil.
Empty and mop out the float bowl.
Leave the needle, seat, and float in position.
With one finger on the float pivot, to keep it in place, have an assistant crank the engine - be careful not to impede the free movement of the float with your finger.
Watch the float, meddle and seat, and the walls for any unusual flow.
Watch for smooth float movement upward, then complete shutting off of the flow of fuel.
If fuel does not shut off, try lifting the float slowly to see if you can make it shut off (you can then bend the support a bit to make it hold that position and see if buoyancy alone keeps the valve closed).

This will definitively tell you whether this system is the problem.

- Eric

Koda

That was some of the finest grade BS I have seen in a while from the seller. Guy deserves a kick in the beans. Of course the problem is not his carb. What a maroon.

I don't understand why he is only overflowing under driving and not idling.

brown7373

On that same line...Did you make sure the old metal gasket came out? Sometimes it will stick to the carb and you don't realize it didn't come out. Double thick gasket would raise the float somewhat.

defiant1

I really want to drive my car, but not looking to shell out more money... but it may come to that.

Good idea. Easy enough to try. Thanks

It is weird, I can rev the throttle all day in park at various RPMs in the garage and nothing. I take it out for a 2 mile drive and pull over to check the intake manifold and everytime it is the same result.

Yep, old gasket came out with the seat.

tds

Next step is to get a 5lb. fire extinguisher and keep it with you (in the car) at all times!!

defiant1

I posted a reply on Cliff Ruggles forum and this is what he posted:

"Pressure test the gasket under the fuel inlet seat. A tiny leak at that location will cause minor flooding.

Install the fuel inlet seat, gasket and needle. Fill the bowl with a soap/water mix higher than the gasket level. Firmly hold the needle down into the seat, and apply some compressed air into the fuel filter housing or inlet. A tiny stream of bubbles will appear if you have a leak.

This is a pretty common problem, we see a LOT of carbs come in here freshly "rebuilt", but leaking under the seat at the gasket due to not clean enough, or minor damage to the seating surface.....Cliff"

I accomplished this with no air leaks detected. I did not have a helper over the weekend, so I could not conduct Eric's suggestion in the above posts. I am sending carb back to carbdoctor (seller) for him to look it over (per his request). Will see what happens.

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defiant1

Well, recieved carb back from carbdoctor. He machined a new "horn" (one of the two that holds the float pin in place) to replace the one that broke off. He machined the air horn to make it more even and sent it back to me. He installed a brand new needle and seat, gasket and float as well.

Hooked it up and still had the same problem of gas leaking around accelerator pump area.

I borrowed another air horn from a friend and still had the same issue.

So I have a pretty looking carburetor that I can't use. I appreciate carbdoctor trying to rectify the issue, but after I replied back with the same issues, he has been "comm out" ever since. So, I cannot recommend him based on the quality of the product I received and not standing behind his product.

I can try sending it to Sparky's or another vendor. But I am so tired of dealing with Qjets and not looking forward to tying up another few hundred dollars in a carb that may or may not work.

Any suggestions?

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pogo69

get another carb...if you know someone local that has one just even to put on to test it i would do that...those q jets are a dime a dozen for rebuild cores and pretty cheap for functioning bolt on ones

MDchanic

+1. Exactly what I was going to say.

Buy or borrow an old QJ, take it apart, blow it out, put it back together (swap the accelerator pump skirts if the one in is dry), and try it out.

If it does the same thing, you know the other carb's fine.
If it runs and doesn't leak, take it through its paces and, if it's acceptable, drive the car with it while you contemplate your next move.

- Eric

pcard

If, in the at rest position, the bottom of the accelerator plunger cup is above the fill slot two things could happen when the throttle is put down: one is some fuel will be sent back into the bowl from the accelerator well, and the second is that there will be a portion of the recovery stroke that can create pressure above the cup in the top of the pump well, which could push fuel past the rod to the top of the air horn, especially if the pump return spring is incorrect.
It would have to be significant to put 8 oz of fuel on your manifold.




There are different pump plungers, with different rods (see Cliff Ruggles' book page 100). I do not know how to tell which is correct for your carb, but I imagine Sparky's or Cliff Ruggles can.




Quote:"It is weird, I can rev the throttle all day in park at various RPMs in the garage and nothing. I take it out for a 2 mile drive and pull over to check the intake manifold and everytime it is the same result."

Perhaps while driving you use a throttle pattern which is different than that while just running in the garage, or the lower vacuum under load is doing something.