gas smell

[tonyk72]

After I let my 'vette idel for about 20 mins today, I pulled it back in the garage, shut the door, came back downstairs, and the whole garage reeked of gas. Is this normal?

 

[MidShark]

tonyk72- It sure doesn't sound normal. Did you pull the air cleaner off and see if there was fuel leaking from somewhere? Maybe a leaking fuel bowl gasket, line, etc.?

Dick

 

[Tweek]

I have heard of many problems of gas odor, and just as many fixes, but mine was the fuel line on the passenger side along the frame right before it bends (at differential crossmember) to go over the rear of the frame, the gas line had rusted from the outside in so slighty that is was bleading fumes and never a drop on the garage floor. I had found it when I was replacing the trailing arms, I pressure washed everything before painting, and it finally started to leak. If it was not for that I would still be looking

 

[Mac]

It could be any number of things, from stem to stern- literally from carb to tank. Hopefully, with some looking around, you'll be able to generalize the area where the smell is coming from and then focus in even closer. No way to do thing without getting dirty.

I had a gas smell which turned out to be leakage around the fuel pickup. I was afraid it was going to be something more serious (ie: tank leak) but when I dropped the tank, it was just the pickup so presto-swapo!!

 

[Pappy]

Check the fuel pump,sometimes the diaphrams go bad and the produce a small leak ,also pull your dipstick and check your oil for gas, I have seen them leak into the crankcase from the fuel pump also.

Regards,
Terry

 

[tonyk72]

Thanks for all the suggestions guys...it's supposed to be nice this weekend so I guess I'll check all those spots.

 

[tonyk72]

OK, after reading some previous posts on the same subject I checked tonight (as I don't wanna blow up my house). I don't know if its related, but it looks like my carb may need a gasket between it and the manifold. Check it out the oil leaking down the manifold...

 

[sidepipe]

Fuel Smell

I agree with TWEEK. My 65 convertible always had a fuel smell when I parked it. No fuel dripping, but always smelled. When I took the body off, the gas line between the body and the passenger frame rail was rusted badly, and the frame was wet. Take your time and investigate all the possibilities that all these people that have "Been There, Done That" present. You'll get it! Good Luck ...........Frank

 

[68Roadster]

Tony,
My 68 is the same way....my wife always complains (&$#@) about the gas smell in the garage.
I have the same problem you have. The carb is where most of the leaks come from. Either the gasket leaks or one of the plugs that's sealed up on the Quadra-Bog. You might try tightening the four bolts on top of the carb also.

I've just learned to live with it although the frame rail stories have my interest peaked......

 

[Brettmc]

I have the same stains on my manifold. It was caused by a leaky Holley 650 DP which I replaced with a Holley 850 DP. No more gas fumes in the garage.

 

[tonyk72]

I sort of clueless when it comes to mechanics...so is it possible for a carb to leak oil? Or is it just the gasket?

 

[Enigma]

Don't know if this will help, I'm a bit late reading this.

In my 80 vette there was a small hairline crack in the fuel line just past the first bend after the carb. It would only leak under heavy acceleration. Drove me nuts for a long time.

Good luck in your search.

Enigma

 

[Mac]

I sort of clueless when it comes to mechanics...so is it possible for a carb to leak oil? Or is it just the gasket?

No, a carb can't leak oil but if gas is slowly leaking, it will cause stains which can resemble oil leaks. The stain is actually residue left when the gas evaporates and if you've got those stains, you've got the gas smell too.

 

[tonyk72]

Well, if you look closley at the pic I attached, right around the intake manifold bolts, there is a small pool of oil. At first I thought the oil was coming up through the bolts. I put some thread sealer on the bolts and torqued them to spec.
This leads me to my next question.
How diffucult is to remove & replace the gasket?

 

[red70vette]

The oil leak my well be a different problem. That shouldn't give you a gas smell. In my 70 SB it was the rubber fuel lines which where cracked and only leaked when the car ran and the engine was torquing. Hairline crack in the rubber line.

When I smelled gas upon my return to the garage I looked and it looked OK. Gas leak stopped when the car stopped and the gas evaporated and created the smell. I finally checked when the engine was idling and there it was wet and leaking very slightly.

Replaced both lines and problrm solved.

 

[tonyk72]

I checked around the carb today and looked around the intake and I found a pool of gas by the intake maifold bolt. Then I was lucky enough to see the gas actually drip from problem area...see attached pic...black arrows indicate where the gas was dripping from. I still have to track down exactly where the leak originates, at least I have a starting point now...

 

[Eddie 70]

The oil on the manifold was just oil that had migrated up the bolts. You have most likely taken care of that problem for the life of the car now. When I fill my tank up I get a gas smell. I am thinking it is one of the rubber hoses leaving the tank. Gotta get that fixed soon. Just getting up to it is the problem.

 

[JohnZ]

I checked around the carb today and looked around the intake and I found a pool of gas by the intake maifold bolt. Then I was lucky enough to see the gas actually drip from problem area...see attached pic...black arrows indicate where the gas was dripping from. I still have to track down exactly where the leak originates, at least I have a starting point now...

Both places are the end of the primary and secondary throttle shafts; fuel dripping from there starts at the booster venturis, drips straight down on the throttle plates, and runs off the ends where you saw the dripping. Normally this is a result of the floats being set too high, or excessive fuel pressure from aftermarket fuel pumps. Older Holleys wear where the throttle shafts go through the baseplate, and eventually need the throttle shaft holes in the baseplate re-bushed to tighten up the clearance.

 

[Brettmc]

Sounds like you need a rebuild on your carb or another one.

 

[tonyk72]

Found some good info which pretty much describes my problem on the Holley website...I was wrong before suspecting it was an oil leak...

QUESTION After I shut my car off and come back out the next morning there is gas on the throttle shaft and puddled on the intake. What causes this?

ANSWER This is usually caused by percolation. This is when the engine is shut off and the engine temperature rises it causes the fuel to boil in the bowl and leak out of the boosters. There are a couple of things you can do to cure this one is make sure the fuel level is not too high. You can also lower the fuel level about 1/8" below the sight plug hole and this will cure it sometimes. The heat from the engine will rise into the carburetor sometimes and will cause the fuel to boil. Installing a phenolic heat spacer between the carburetor and the intake or a heat shield can cure this. These parts will prevent heat from getting to the carburetor and boiling the fuel.

http://www.holley.com/HiOctn/TechServ/TechInfo/Trblsht.html

I got this from the Holley website, great source of info!
John, it looks to me like that relates to what you were saying?
I also suspect that I have an incorrect (thin) gasket which contributes to the problem...but I have no way of telling what a thin gasket measures to a think gasket...