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Topic: Gas Leak?

in Forum: C3 Fuel, Emission Control, and Exhaust Systems

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Gas Leak? (1/19)
7/10/10 10:36pm

KDADDY79
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Dutchess County, NY - USA

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'79 L-48 / Original Q-Jet carb. (rebuilt) / Edelbrock Performer Intake

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Recently I have noticed a brownish colored stain on my intake manifold right up in the front between the carb. and the T-stat housing. It is not wet, just a bit dirty. It smells like gasoline.

I have looked above this area on the front of the carb. and have not found any disconnected lines or hoses. The fuel line is tight.

The motor seems to run fine / No fuel starving or such.

I'd like to straighten this out before it develops in to a bigger issue.

Any ideas?

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Gas Leak? (2/19)
7/11/10 11:42am

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The carb is seeping fuel. Could be from the filter inlet, since it is in that area. You say the fuel line is tight, but is the fitting that the fuel line goes into also tight in the carb? There is a really thin nylon gasket that fits onto the end of the filter inlet, and that thing will seep if it is damaged, or loose. IT isn't enough of a leak to be visible, but it will seep out over time, and stain the intake like you describe.
It could also be a crack in the fuel bowl, but the fuel inlet seeping is more likely. I would suggest removing the filter inlet, and replacing that gasket on the end of it first. You can clean the intake, and get it dry, then place a paper towel under the inlet overnight, and see if there is any indication of seepage at that location.

Adams' Apple2010-07-11 08:44:08

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Gas Leak? (3/19)
7/11/10 4:08pm

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Holland Patent, NY - USA

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I hate "seepage"

Evil Smile ebo

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Gas Leak? (4/19)
7/11/10 5:44pm

KDADDY79
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Dutchess County, NY - USA

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Joel,

I think we nailed it! The large nut on the portion of the carb. where the fuel line attaches was just a tad little bit loose. With the wrench on it was a small fraction of a turn, but some movement none the less.
After that I started it up and let it run for 10 minutes. No leaks. After an hour of cool down, no leaks. I am letting it cool down for a few hours with a folded paper towel under the area in question.
Can't say what could've caused that to become loose but it looks like I'm in the right place.

Kevin
KDADDY792010-07-11 14:50:20

Gas Leak? (5/19)
7/11/10 5:58pm

KDADDY79
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And as for you Mr. ebo man;
Yeah, I guess I left it hangin' out there with words like seepage and brown stains. Now didn't I.
'Figured you'd be lurkin' out there just waitin'.
Ah well, no diapers for me yet.
Hopefully a good running Vette and good health will allow me to catch up with you guys later this season.

Gas Leak? (6/19)
8/21/10 12:23pm

KDADDY79
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Dutchess County, NY - USA

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Well, it seems like this problem has reared its ugly head again.

After a 10 mile ride this morning I noticed the odor of gas fumes. After a look under the hood the same stain is present on the intake manifild and gasoline is definitely dripping out of the same location as before.

Again I put a 1" wrench on the large nut where the fuel line enters the (Q-Jet) carb. A very small turn of the wrench and the problem is solved........for now.

Any ideas on what I could do to keep this from reocurring?

Question

Kevin

Gas Leak? (7/19)
8/21/10 2:57pm

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Flanders, NJ - USA

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Hey Kevin, do you know how to weld Rolling On The Floor Laughing

Rolling On The Floor Laughing

Maybe some sealant on the threads? Not sure about that with the gas you need info from someone with more smarts about carbs than me. Good luck, hope to see you this fall.

Dave

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Gas Leak? (8/19)
8/21/10 4:34pm

indy99
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Newport, MI - USA

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I'm thinking the fuel line may have a small split in it on the end. You will need to remove the line from the carb and examine it. A new line is not too hard to replace. DB

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Gas Leak? (9/19)
8/22/10 1:08pm

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Gonna have to replace the gasket, IF it is leaking from the fitting going into the carb. Once tightened so far, the gasket will split. AS Dennis mentioned, the fuel line itself can develop a split, or the flare can be crushed enough to leak.
One trick to a temporary "fix" for the gasket is to run a couple rounds of sewing thread around behind it. You want to put the thread between the gasket, and the fitting, where it seats. This will make the gasket "thicker", basically, so it will seal. IF the gasket is actually split tho, this won't do any good, and will prolly make it worse.
My suggestion would be to remove the fitting, and replace the gasket. I don't know that you can get that gasket by itself...it does come in a carb O/H kit, tho...

(Tanx, Ken

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Gas Leak? (10/19)
8/22/10 9:21pm

KDADDY79
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Dutchess County, NY - USA

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Hey Fellers,

Thanks for the input on this.

I checked Auto Zone for just such a gasket with no success. The guy behind the counter might have been wingin' it. He told me the Edelbrock rebuild kit would have the gasket I need. I just was'nt sure he was right, so I held off. Maybe just a bad vibe, I dunno.

There are a few other local places I'll try for just the gasket. And I'll hope the fuel line is ok until I take it apart.

Gas Leak? (11/19)
8/22/10 10:24pm

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Flanders, NJ - USA

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Get some gasket material and cut your own using the old one as a guide.

Dave

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Gas Leak? (12/19)
8/22/10 11:03pm

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Won't work, Dave....

This is a very thin, nylon gasket/seal. It fits around a small lip on the fuel inlet fitting, as you can see from the pic I posted above.
Kev, I may have a few of them in my carb box, if you can't locate one locally. I would suggest asking your local mechanic, or a carb shop, if you have one in your area. If you can't find one, send me a P/M with yer address, and I'll throw one in the mail for ya, providing I can find them.
Adams' Apple2010-08-22 20:05:05

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Gas Leak? (13/19)
8/23/10 8:34am

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HOWELL, NJ - USA

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Kevin, Go to a parts place that has one of those "Help" parts isles. They have a package of various carb gaskets. Bring the fitting with you and see if you can match it up. Sometimes those packages "accidentally" open so I can make sure it's the right one. Wink

Wink

I does buy the package iffin it matches tho...

Gas Leak? (14/19)
8/23/10 1:04pm

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[QUOTE=lukesvette] Sometimes those packages "accidentally" open so I can make sure it's the right one. Wink

Wink

[/QUOTE]

So YOU'RE the one that does that?!?!? Angry

Angry

I have a Pep-Gurls right next to the shop here, and about half of the "Help" packages have usually been opened over there. Sometimes, they gots tape holding it back together, and sometimes staples, but most of the time, you pull the package off the hanger, and the crap just falls out on da floor!

I never thought about looking there, tho...good call there Paul!

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Gas Leak? (15/19)
8/23/10 7:37pm

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HOWELL, NJ - USA

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We all have our weaknesses...

Gas Leak? (16/19)
8/24/10 8:21pm

yostusota
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I did have some input on the brown stain..make sure that you tighten the fuel filter first then the fuel line..it may tweak the fuel line then vibrate the filter loose..I looked for one of those gaskets but didn't find any..I use them whenever I rebuild the carb I am working on..I did just see commercial for pep nuts and they are having dollar days..maybe that open box in the help section will be worth it being half the stuff is missing..
Rich

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Gas Leak? (17/19)
8/24/10 10:10pm

dskopp
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Oak Creek, WI - USA

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You all are abunch of bad boys. Censored

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I would never open a package in the store!! Wink

Wink

I would put it in my pocket first, then take it outside and open it !!! lol

Dan

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Gas Leak? (18/19)
8/24/10 10:49pm

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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

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[QUOTE=yostusota]I did have some input on the brown stain..make sure that you tighten the fuel filter first then the fuel line..it may tweak the fuel line then vibrate the filter loose.
Rich [/QUOTE]

That's a good point, Rich... I've had that happen!

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Gas Leak? (19/19)
8/25/10 6:06pm

KDADDY79
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Dutchess County, NY - USA

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A local carb. shop had them. The guy there is not a big fan of the Q-Jet but for this he was right on the money. That was a whole bunch easier than I thought it would be.

Joel, thanks anyhow for offerin' to send one my way.

Another slam dunk by the fine folks here at C3VR! Thumbs Up

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Kevin

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