I have a 1957 Chevrolet Nomad with a small V8, high-performance air intake, carburetor, etc. If I don’t start it for a few weeks, it seems that the fuel tank will suck all the fuel back. I tried to install a check valve, but it didn't help.

I have owned this for 48 years. Apart from installing an electric fuel pump, do you have any comments on what might cause this situation? Thank you, and be safe. -John

Ray: That's the built-in anti-theft device, John. In fact, your theory is logical, John. But it was also wrong. Like many of my theories.

Your problem is not that gasoline flows from the carburetor and back to the tank along the fuel line. The problem is that gasoline leaks from the float and evaporates.

This is how it works. When you turn off the engine, your carburetor stores a pile of fuel in the float chamber. That is the fuel you will use the next time you start the car.

In fact, if you cut off the fuel line from the fuel tank, your car can still run for a minute or more on the fuel stored in the carburetor. But you must write to tell me how to replace the fuel pipe, so don't do that.

In any case, it takes a few seconds for the fuel pump-during the process of starting and starting the starter-to provide enough new fuel for the carburetor to run the engine.

Normally, this is not a problem because, as I said, you have enough fuel in your carburetor before the fuel pump catches up.

But as far as you are concerned, during the few weeks when the car is parked, fuel leaks from your carburetor, may enter the intake manifold and evaporate. So, when you start the car, the float chamber is dry.

Now, I think you can install an electric fuel pump with a switch on the dashboard. You can turn on the switch a few seconds before you want to start the car. This will fill up the carburetor.

But you will be smarter if you only replace the carburetor. It may have cracks or other problems that cause gasoline leakage. If you eliminate the leak, who knows, you might increase from 9.4 to 9.5 miles per gallon.

Lucky break-hope-after the jumper accident

A few weeks ago, when I was waiting for a car in the parking lot, someone asked me if there was a jumper. I did it.

The questioner said that an approaching pickup truck made him jump, but there was no cable. When positioning the pickup, I connected the cable to the dead car's battery-correct (red to positive and black to negative).

When the pickup driver picked up the other end of the cable, I said, "Be sure to put the red clip on the positive pole." He retorted, "I know what I'm doing!" Well, he didn't. When he put them on, the red clip on the dead car really exploded, melted a part, and then bounced off—he turned them upside down.

When I told him he put them on the wrong terminal, he was really angry instead of admitting his mistake. When he did put them on the correct terminals (I checked), I was able to put the damaged clip back on the positive terminal of the dead car battery, and the car started.

The owner of the dead car voluntarily bought me a new jumper cable, but I refused. But this makes me very curious. As far as I know, the only damage is the cable clamp on the jumper. It is small enough that when I got home, I fixed it with my Dremel and it was still very useful.

But could this error cause any damage to the dead car or pickup? If so, which one might be damaged? - Cary

RAY: Cary, any of them may be damaged, but none of them sound like (sorry, I know you want the pickup to be blown up).

My guess is that before any electronic equipment is damaged, the spark generated when the pickup was connected to the last wrong cable blows the battery clip off the battery.

Of course, this is my guess. As far as I know, pickup truck drivers may now set the seat heater to "scorched" every time the windshield wiper is turned on. The AM radio of another person may be coming in from his heater.

Although if the electronic module is damaged, the electronic damage may appear later, but it usually manifests immediately. So, I still hope that your jumper cable is the only victim here.

If the cable stays there longer, there will be many electronic devices that are sensitive to voltage surges. Most modern cars now have 30, 40, or 50 computer modules that can participate in everything from engine management to power windows. This is where the damage is.

But I think you are all lucky enough to rest, Cary. The jumper cable that conveys our desire for a speedy recovery to you.

Have questions about cars? Write to King Features of Ray, 628 Virginia Drive, Orlando, FL 32803, or send an email by visiting the Car Talk website www.cartalk.com.