I recently purchased a 1971 convertible, base 350 automatic. When I topped off the fuel tank for the first time this year there was very strong fuel smell, really bad in the garage. The lines all seem ok anf there are no apparent leaks but I have not dropped the tank to check closely.
Any thoughts on the cause? Thanks

 

Hi MRD,
Welcome FIRST post!
And a new old Corvette for you.
How about a little info and a few photos of it?

Did you notice a gas small before you 'topped off the tank?
Might you have over filled it?

Your 71 is designed with a sealed gas tank so any gas smell in the garage should be quite minimal.
There are several parts to the system:

Supply and return lines to the fuel pump. Check the hose connections at both the tank and fuel pump.

The gas cap should be of the 'sealed' type. Check that the gasket that's part of the cap is in good condition.

There is a vapor control system that consists of a vapor separator mounted on the left side of the tank with rubber hoses from the tank to the separator and from the separator to a steel line on the frame rail.
The steel line runs forward to a vapor canister that mounts behind the left front wheel apron. There are 2 rubber hoses that run from the canister to the carburetor.
Check the condition of the hoses. The separator can be removed... when shaken there should be the sound of a marble in it.

The smell could be caused by any of these parts not functioning, or deteriorated rubber hoses, or poor hose connections.
You might begin by assessing which of these parts are indeed on your car.
Good Luck!
Regards,
Alan

The sealed gas cap.


The supply and return lines.


The vapor separator, and hoses.


Vapor canister mounted on wheel apron.


The hoses running from the vapor canister to the carburetor.

 

Alan,
Thanks for the detailed pictures! Much appreciated.
The system looks to be complete but I really need to get it up on a hoist and check the connections etc.
I don't think I over filled the tank but the smell as subsided after driving the car to the point where I'm at a half a tank.
Mark
I don't think I overfilled the tank but the smell was only present with a full tank.

 

Hi Mark,
You should 'feel' the connections too.
Even just the 'weep' from a deteriorated hose can give off quite a gas smell in a closed garage.
Regards,
Alan

 

Thanks again Alan, I appreciate the tip. (Any Tips!)
For the most part the car seems pretty well put together , but........ I've discovered a few things that make me wonder.

Regards,

Mark

 

Welcome to the forum.
We always like to see photos of peoples cars.
I had the same issue with my 73 when I purchased it, brought it home and parked it in my garage.
After days of tracking the source I found the vapor separator was cracked and replaced it.
No more fumes in the garage.

 

True about "weeping". I used a bright light under my car to check the rubber hoses. They "looked" good and felt dry, but when I flexed the hoses, later on the gas smell in the closed garage was strong and the hoses had just enough wetness soaking through to prove they were actually dry-rotted.

 

dont forget about the cork gasket between the tank neck and the body of the tank. Remove the gas door, remove the gas cap, remove the rubber apron. Reinstall the cap and gas door and fill up the car almost to the very top of the neck. Watch the seam between the neck and the tank for leaks.