I have a 87 LT with an LG4 with the 4 barrel carb and I just replaced the fuel tank, pump and cleaned the fuel lines because the car has been sitting for a while.

When I try start it, it turns over but the carb spews gas out of these two openings. It has yet to turn on. I’m confused if I made a mistake or am I missing something here.




Leaking fuel out of these openings while turning over.

 

Sounds like either there's a layer of old varnish (dried fuel gunk) gluing the needle & seat in the carb together in the open position, or abuncha crud got dislodged and has now migrated to the needle & seat, preventing it from closing off the fuel input when the bowl gets full. Same basic cause in either case, just a different mechanism by which it applies itself.

So, no, not a "mistake" really, just a natural but unintended unfortunate consequence.

I also notice that it looks like the fuel filter hasn't been disturbed lately, meaning, it's probably also full of crud. It's inside that big nut right next to that Fuel Leeeeek Of Death you can see in the extreme lower left corner of your pic; which in turn probably is the result of somebody trying to get to it, and not holding the big nut with a wrench while trying to undo the little nut that hold the line in the big nut. They pretty much destroyed the line nut in the process and just cut the line and put in that guaranteed fire source instead. That's a disaster just waiting for the right time to happen. Butt change out the filter regardless; makje sure when you put in the new one, you put the spring in first, then the filter with the metal end against the spring and the rubber end showing, then screw the big nut back on CAREFULLY so as not to strip the threads in the carb.

 

Check your fuel pressure also. If you put a stock replacement pump on there's a good chance it's putting out more than the required 6 or so psi. My son and I ran into this exact situation on his '86 LG4. Replacement Carter pump had the carb spewing fuel just like you described. We had to add a pressure regulator to bring it down and that stopped the leaking.

 

Seems like AHELLUVALOTTA trouble when merely doing away with that and putting the right STOCK REPLACEMENT FP on it would have cost a fraction of that, and of course, solved the "improvement" problem. Not "advice" I'd give anybody, even if it worked well enough for you that time.

 

He wasn't suggesting adding a pressure regulator, he was recommending the OP check the fuel pressure, then pointed out he did that and discovered a problem with the "STOCK REPLACEMENT" Carter pump he put on. Pretty good advice, actually. I too have found that many "STOCK REPLACEMENT" parts you get at the parts store often are not actually "STOCK REPLACEMENT", and sometimes exploring alternative solutions is more practical than trying every brand part at the auto parts store hoping they are actually a "STOCK REPLACEMENT".

In this case, checking fuel pressure is a good added option for the OP after he explores the other advice (like yours).

 

STOCK REPLACEMENT fuel pumps for our cars don't put out 6 psi unless they're SERIOUSLY defective.

The person speaking of CARTER fuel pumps never said STOCK REPLACEMENT. Let's not put words HE DIDN'T SAY into his mouth (keyboard) any more than we should put words into MY mouth, or YOURS, that weren't said.

It's certainly true that Carter makes stock replacement fuel pumps. Hell, they made Q-Jets FOR YEARS, after the Rochester plant burned down and GM had FORTUNATELY contracted out some of their production to Carter, so Carter had tooling to fulfill the contract. Carter also makes NON STOCK REPLACEMENT fuel pumps for racing type applications, which when somebody says "Carter" as opposed to "stock replacement", is more likely to be what they're talking about. Those pumps are NOTORIOUS for not working well in STOCK REPLACEMENT situations. For example, many of them don't even include a return line provision.

"Checking fuel pressure" in a carbed situation with STOCK fuel lines and whatnot, is all butt impossible. Besides, last I checked, a STOCK REPLACEMENT fuel pump from the OEM (Delphi, they call themselves in 2025) was less than $30 down at the corner parts store; AHELLUVALOT cheeeeeeeeeper than a gauge, adapters, lines, etc. etc. etc.

While I'm not usually an advocate of strafing a car with the full-auto chain-drive parts cannon, there are times when the simplest, cheeeeeepest, eeeeeeeeezyest, most direct means of troubleshooting, is to swap it out. This might well be one of those cases.

All this of course, assuming (yeah I know) that he's already verified that the carb isn't full of 50-yr-old solidified fuel residue and insect nests and whatever all else. In NO UNIVERSE would the first go-to attack be, to add a regulator. ESPECIALLY NOT if the fuel pump that had got put on it wasn't STOCK REPLACEMENT.

See my signature for a helpful mental discipline. Concentrate on the word "likely".

 

I also had issues with 2 Carters and an Airtex putting out too much pressure vs the stock unit. Instead of getting a FPR, I found a NOS AC fuel pump and the problem was solved.

 

If you could just stop rage typing for a minute and READ you might learn something today. Take your meds, angry couch potato doesnt really help anyone here.

Edit: I went ahead and put the important part of the quote in ALL CAPS again, plus BOLD so maybe you can see it now.

 

I'll ignore the personal attacks and concentrate on the matter at hand.

A PROPERLY WORKING, which is to say NON-DEFECTIVE, CORRECTLY INSTALLED, STOCK REPLACEMENT fuel pump won't put out 6 psi, let alone, above that.

Concentrate on the words in bold. Pretend you're the OP and not just some a$$hole schmoe with a hard-on for arguing with me over everything I say (this being FAR FROM the first time you've started a fecal storm like this). I know it's tough, butt bear with us all for a bit here. Attempt to HELP the OP instead of arguing with me. Pretend also that you're looking for the quickest, cheeeepest, most direct, least labor, and otherwise MOST SATISFACTORY WAY to get from point B (carb is "spewing gas" after replacing various stuff) to point A (drive the car). Keep in mind also that this car has been sitting up for awhile, so it's not like it was all happy one day and then they did whatever work to it and it started doing this. Rather, ALLOW the OP's situation to penetrate your skull and make a neuron fire. "Car has been sitting for awhile" triggers all sorts of potential issues ALL BY ITSELF, independent of "spewing gas" or what the OP has already done to it to bring it back to life.

Now that we've got your mighty intellect directed at THE PROBLEM instead of at ME:

What are the MOST LIKELY causes of a carb "spewing gas" out the top?
.

1. Junk in the needle & seat
2. Needle and seat, or float, stuck due to varnish etc. buildup
3. Return line from pump to tank not hooked up (let's roll up all the details of how this could be into ONE bullet point, including that it's simply missing or whatever, or, the pump lacks the fitting for it, i.e. it's NOT a "stock replacement")
4. Return line plugged up somehow
5. New fuel pump is defective out of the box

Among those 3 things, which although certainly not "the only" potential causes of this, I'd venture to guess will cover probably all but one in a thousand such cases.

Now which are the MOST LIKELY?

Right: 1 & 2. Time to pop the carb apart and make sure the needle valve is clean and free to operate, and the float free to do what its name suggests. For that matter in a car that's been sitting up, the carb itself may well be so full of varnish that it needs a teardown cleanup and rebuild ANYWAY.

I'd add that somewhere in the process of all this, it'd be A Good Idea to glance down at the pump, and verify that the return line is hooked up. If not, either find it and hook it up, or get a pump that has it, or whatever else it takes, so that it can be hooked up. Might be A Good Idea to blow out the return line back into the tank, if that hasn't already been down, to verify that it's unobstructed.

So there we are. Haven't spent a dime on anything but a carb kit and filter, which it most likely needed ANYWAY.

OK fine, all that is now in order, does it still spew?

No: close the hood and drive the car.

Yes: maybe the new FP is defective. It is ABSOLUTELY possible. Not particularly likely I wouldn't think (I've only changed out about a hundred of em in my day and never ran into that, butt hay, it can happen, right??), and CERTAINLY not the MOST likely cause of the symptom. IOW, there are other possible "explanations" to investigate FIRST, before that one. Butt then, if it turns out that that's The Problem, handle it. Take it back and warranty it, or if they won't, or can't because it's been installed, just buy one. They're CHEEEEEEEEP and EEEEEEEEEEZZZZZZZY to replace anyway.

OK, now we've spent $30 more or whatever, or maybe not.

Explain to me how buying a gauge and/or a regulator and whatever fittings it takes to hook it up, is ANY CHEEEEEPER OR EEEEEEEEEEEEEEZZZZZZZZYER OR QUICKER than the above. Most of which the car probably needs ANYWAY, and would need ANYWAY even if the carb wasn't spewing.

Correct answer to the OP is, HELP HIM FIX THE CAR with as little dinking around and expense as possible, no? Not, "I put a [fill in the blank] on mine and it fixed it". Not, attack me. Not, conflate what other posters have said, with what the OP said, or what I said.

 

More rage typing. Put down the Vodka bottle for a minute and just appreciate that I recommended the OP explore his other options first. Hence this quote from me earlier:

 

Right.

How??? At what cost??? How much labor??? How much destruction to fuel lines and whatever all else just to hook it up, let alone UNDO whatever all gets disturbed in the process???

Then? He'll find out one of 3 things.

What if he finds out his fuel pump is good? All of that effort is WASTED.

What if he can't tell if his fuel pump is either good or bad? (let's say, he has 5 psi or something) All of that effort is WASTED. He STILL doesn't know what to do.

What if he finds out his fuel pump is bad? All he can do at that point is REPLACE IT, at its trivial cost and effort and molestation to the vehicle, as compared to all of the above for "check fuel pressure". Which is THE VERY THING I'm telling him to just go ahead and do ANYWAY, once he finds out that all of the actual LIKELY (er) things aren't the source of the issue. There's NO NEED for "check" anymore at that point, even if he ever gets there in his process, which isn't likely.

"Check fuel pressure" isn't on the same level of accessibility, ease, expense, etc. as some other "checks" are; like checking voltages with a multimeter or something.

Consider also the LIKELY level of tools, experience, knowledge, etc. that the OP has. If he's the kind of person who is asking why his carb spews gas out the top, then the odds that he has ANY of the stuff to "check fuel pressure", or that he could successfully pull it off without opening some other can of worms, is pretty slim.

Go attack somebody else. You're just WRONG in telling him to do that and you're too stubborn to admit it.

OP, I apologize on Aaron's behalf (since he's not the kind of person that apologizes for ANYTHING no matter how much of a fool he makes of himself or how annoying he is) that he came in here and acted an idiot and tried to ruin your attempt to find out how to diagnose your car SIMPLY with a load of USELESS crap. I hope you'll overlook his rudeness, and I look forward to hearing from you that you were able to identify and straighten out the problem without buying and installing abuncha gauges adapters and whatnot, that all they would tell you to do, is what you'd be doing anyway, if you even ever got to that far along in the whole revival from storage process (i.e. hadn't already fixed it).

 

Well this conversation got ridiculous so I asked AI to make a picture of it. AI is stupid, that is clearly NOT a Thirdgen.

 

I guess since you can't win an argument on the merits because your whole idea is WRONG, you have to resort to even more of these juvenile personal attacks.

Instead of grade-school playground taunting after you've been clearly beaten by logic, how about you tell us all about exactly HOW somebody is gonna "check the fuel pressure" on a Q-Jet, how much it will cost, how much effort it will require, and how that compares to the cost ($25.49) and effort of JUST CHANGING OUT THE DAMN PUMP (if it even turns out to be suspect after fixing all the "sitting for awhile" issues, which is highly doubtful to begin with) and moving on. https://www.autozone.com/external-en...002/340217_0_0 Assuming even, that he reaches that point in his troubleshooting, after cleaning out all the crud and varnish, and refreshing the carb. IOW you are NOT ONLY wrong, BUT ALSO arguing pointlessly about abuncha USELESS CRAP that probably won't ever make any difference anyway.

Have a WONDERFUL day!!!

OP – NOT Aaron – I would note however, that when you said you replaced the pump, we out here can only assume (yeah I know) that you replaced the one like I linked to; and not one in the tank. Reason being, it would be VERY POSSIBLE to have put in an in-tank fuel injection pump, which could produce MUCH too high pressure for a carb. Fill in that detail please, of EXACTLY what pump you put in.

 

*Same way we've tested fuel pressure on these cars for decades
*Tool rental cost from A-zone? ($0.00 after tool return?). Or perhaps the OP already has a fuel pressure test kit?
*According to ProDemand, 0.5 hr. I'd say that is generous.


I can't believe this is the reasoning for NOT checking fuel pressure. I'd write my staff up if they came to me with that list of excuses, to not do easy work that ends guessing, with objective data.

 

Last I knew, AZ only had ones in EFI ranges (like 0-75 psi or something) which makes it kinda hard to read down around 5 psi. Butt you can get one for typical carb usage from Summit and such, seems like they're around $25 for the cheeeeeeepest (about the cost of a fuel pump).

And THEN, as said, he'd need a way to hook it up to his Q-Jet system. 3/8" inverted flare fittings and all such as that.

As said, I don't KNOW this for a fact, butt I'm GUESSING that anybody that would need help with a carb spewing gas out the top, won't have the wherewithal for any of that.

Butt as also said repeatedly, he needs to go through the LOGIC process and eliminate all the FAR MORE LIKELY things and take care of all the stuff like carb varnish that are virtually certain to be present, before worrying about that. Unless, as said, the fuel pump he installed, is an in-tank EFI one, in which case, it's WRONG no matter what any gauge says, and needs to come out and be dealt with. He doesn't need a gauge for that.

 

Look at the product specs. It very clearly states minimum pressure 9 psi, maximum pressure 11 psi.

I'm not at all saying your suggestions are wrong. I'm simply sharing what worked for us. Carb was freshly rebuilt, everything was hooked up correctly, tank was verified clean, supply and return lines to/from the tank were blown out, hard line from the pump to the carb was cleaned out, new Wix filter in the rubber line to the pump, new filter in the carb inlet. Zero chance our carb had any trash in it and it overflowed like crazy.

The pump I put on my son's car was a Carquest 160577...which was a rebranded Carter M6626. Definitely the correct stock replacement (which you're right, I didn't exactly say that). Specs on that pump say minimum 2 psi, maximum 9psi. So like the Delphi, if it's puts out more than 6psi, that doesn't mean it's defective.

NOS pumps are scarce. I found one on Ebay but didn't want to roll the dice on something 40 years old. The Carquest pump has a lifetime warranty and is easy enough to change.

 

OP, since you've got a rubber line on the carb inlet, pinch it to restrict flow and see if that stops the overflowing. Wouldn't definitively confirm an overpressure situation but you can use that to aid in your troubleshooting. If pinching the line helps, you could easily splice in a cheap pressure gauge to verify pump output. Given how poorly everything is made these days, there's a good chance the cheap gauge will leak immediately and then you can return it for a refund.

 

This screams gummed up quadrajet, especially seeing as it has sat for a while. Step one should be clean out and rebuild the carb IMO, it's never a bad thing to do to a carb that's been sitting a while.

If it's still spewing gasoline after, OP can fairly easily tee into that rubber hose fire starter at the carb and test fuel pressure just to verify he's getting the correct pressure at the carb. I do recommend fixing that rubber hose with PTFE AN lines and fittings also. What's the part number on the pump you put in?

 

This is one of teh stupidest "conversations" a (decent) mechanic can have w/a mechanic type person. But I'll play for another minute, for the sake of the forum....not for your benefit.

Vacuum/pressure gauge. You can probably get one for about $12*. I haven't looked. The OP may even have one. Or he could "rent one", w/the FP kit that we're assuming he doesn't have.


Any decent tech would know that a decent fuel pressure test kit would come with all of the adaptors necessry to "T" into the space between the pump and the carb. BUT, you've inferred that the pump he's using is or may be an in-tank electric. Right? RIGHT. That means that there is a rubber line that runs from the frame to the engine, somewhere. That is your location for a super EASY-PEASY "T" installation, w/o any cutting or other horrifying things that you've dug deep make "mechanic drama".


That's what we're here for. To give GOOD help.


There is a testing process, (that good mechanics are aware of), too. Testing > Guessing. We're here to guide people with GOOD advice. Right? RIGHT. That is very simply....what Aaron R was doing. His advice was sound, it was GOOD advice and it was good, b/c it's not a WAG, and it will lead to objective data to help the OP w/his problem.

*EDIT: I just looked. Well...****. I was by a staggering, $2.99. Gosh darn it....I don't know, anything!

As you were, sofa.

 

Naah. I am in AZ and have a low-pressure fuel gauge. Neighbors who lived in their house 40+ years and moved gave it to me. I don't know how I lived without it. That, and my dwell meter, set to 6cyl. scale, brings me peace, knowing I can pass a 50 state emissions test.