Gasoline smell

[babaron]

Everytime I take my '69 L78 out for a spin and park it in the garage, it seems like the smell of gas is strong for the next 24hrs or so.  Is that normal? I do leave the hood open as I have it hooked to a trickle charger.

[JohnZ]

That's today's gas boiling in the float bowls during heat-soak after shutdown and being forced out of the boosters. A phenolic spacer under the carb can help, as can an aluminum heat shield under the float bowls. Or, you can leave it outside with the hood open to cool down, then run it just long enough to pull it into the garage.

[pjbizjak]

It's possible you have a small gas leak at a fitting or in the fuel line or even a pin hole in the gas tank that's not noticed until the car is running and it probably drips on a hot part where it evaporates so no dripping on garage floor. John Z's answer is more technical and probably correct.

[mikefam]

There's so many things that can cause gas odor that you really are going to have to do some troubleshooting to find the cause.

To oversimplify the problem, gas is escaping the fuel system and you're going to have to find the leak. What makes it difficult sometimes is that it may not be an external leak. It's relatively easy to find an external leak by giving the fuel system a visual inspection from end to end. If that doesn't turn anything up I would look at the carburetor next, especially if it's a quadrajet carb. If gas is leaking internally in the carb you will smell gas just as if  it was leaking on the floor, you just can't see it.

I've been struggling with the same problem with my 67 327 w/quadrajet and am still going through a process of elimination. I smell gas when parking the car hot and then it's hard to start about twenty minutes later. To make a long story short and save a lot of typing I'm pretty much convinced that the gas in the carb is boiling when I park the car with a hot engine. So far I have rebuilt the carb and determined that the float valve is not leaking and replaced the fuel pump to no avail. The next time I remove the carb I plan to install a modified float valve that prevents gas from leaking back to the fuel tank and plug up the exhaust port in the intake manifold under the carb base to keep the carb cooler. I may also tie my heat riser open to help the engine to run cooler.

If you search this forum and the net you'll find loads of information on your problem.

Good luck and have fun with it, Mike.

[babaron]

Thanks, Mike.  I found the leak.  It is the Holley carb.  Should I change gaskets or do a rebuild?  It's missing the choke and the car stalls during hard braking too.

Ron

[mikefam]

Ron:

Sorry I didn't get back to you sooner but I've been away from the computer lately.

I say rebuild the carb, rebuild kits are cheap and it's good to clean things up occasionally.  Also make certain that there are no vacuum leaks before looking for other problems. You can search for vacuum leaks by spraying WD40 at gaskets surfaces and suspected leaks while the engine is idling. If the rpm changes when you spray the WD then you have a leak.  Also do a complete tune up if it hasn't been done lately.

Carburetors are complicated and tough to troubleshoot in a message forum like this but I'm more than happy to share what I can. Stalling when braking can be that the float level is too high. Or maybe a vacuum problem with the brake booster if you have power brakes? 

Clean and rebuld the carb, tune up, and then troubleshoot.

Mike.

[Kelley W King]

Sounds like a carb rebuild to me also. Having 3 cars with Holleys and getting frustrated by my own rebuilds, I found a retired drag racer in Efland NC who only does holleys part time. He was very specific about the kits he uses new more about Holleys than anyone I know. He has rebuilt several since for guys around here with great results. He also gave me a tip about (that leaky Holley). The accelerator pump gasket gets wear everytime you touch the throttle and is the most likely culprit. They are cheap and easy to install. I keep several in my shop. As I go around car shows I see cars with aluminum intakes with the orange tint under the front throttle side of the carb and I know they need one.

[babaron]

Any idea what he would charge for a complete rebuild?  I know it needs a choke and replating.  If not, could you give his contact info?

THX

[68rs327conv]

I had my carb rebuilt here by Eric Jackson


http://www.vintagemusclecarparts.com/index.html


Mike

[babaron]

just sent carb off to JM for a rebuild.  Couldn't live with the risk of fire. It needed a choke too.  I'm sure it will be perfect when I get it back.

[Boyds68Z]

I have a 68 Z/28 I bought in 2014. Back in 1974, I had the same looking beauty. Back then, I remember the satisfying odor of my car after out for a cruze. That car was, unfortunatly, stolen from me. But in 2014, found the same looking car and bought it. After a cruse, I get the same odor in my garage as I did with the one in 1974.  I love it but wife doesnt. Should I worry about it? I don't have any leaks.

[Rick68]

I have the same issue. Fuel odour and wife complaining!!! I have an L78 and it has done that for years. Car runs great and have no issues.  I would lean towards what JohnZ said earlier. I always tell my wife that we won't have to worry about mice in the garage