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We have a 1968 Torino GT Converible Cobra Jet that goes into a vapor lock at 205 degrees?

When driving cool it runs great but as soon as temp gets to 205 degrees and idling, it start to bog down and shouts off. When engine cools it will start right up. It has a rubber gas line that feels very warm, we put a sleeve over rubber hose and didn’t help. What do you think?

The first thing I’m going to ask is, does the gasoline you run in the vehicle contain ethanol?


it has 87 octane. We just got it last night. the person who has last drove it VERY little and not that far. We dorve it 150 miles and died 5 times. We would let it sit for 15 mins and it would start right up and run GREAT… As soon as temp got back up to 205 it would die. We have two fans going. Not sure what to do. Gas line runs over engine and tubbing would get very hot . Tonight we tried the sleeve and it didn’t work

Forget the octane. Does the gas you use contain ethanol? Go look at the pump where you filled up last and see if the gas contains ethanol. This could explain everything.


We didn’t us old car gas… We where in a town where we didn’t know so we just got gas. So run gas to empty and try the good stuff??

If for the sake of discussion the problem is indeed a vapor lock problem (leaving Ethanol out of this for the moment) you might consider adding an insulator block between the carburetor and intake manifold. These fiber spacers are about a 1/4" thick and can help prevent some of heat transfer from the engine into the carburetor.

The problem could also be caused by a carburetor fault such as a leaking power valve or mixture adjustment which is allowing the engine to load up at idle. This is essentially flooding it out a bit.
It’s also assumed by me that the choke is not sticking partially closed.

It’s also possible for a problem like this to be caused by an excessively hot ignition coil or condenser.

Nice car by the way; especially as a CJ. Back in the day, one of my uncles bought a brand new 1969 Torino GT and drove it to Mardi Gras as a shakedown run.

Low fuel pressure allows vapor lock at lower temps. In addition to other suggestions this could be a sign of a bad (or going bad) mechanical fuel pump.

how do I test stuff vapor locks etc?? Never had a car do this. Had a 69 mach 1 drove like a dream but had a widsor in it. Also on the hood there is two/three, 3 inch holes above air cleaner. We have a scoop that covers them. There is a liner that covers the holes would you cut open so there is more air flow into motor. if I do this you would see it has a shaker cover on hood top.

I had the same problem with a '56 Cadillac I owned many years ago. I was told to wrap tin foil around the fuel lines. This worked somewhat but installing an electric fuel pump cured the problem once and for all.

To test the choke thermostat and the system: Loosen the three screws and rotate the choke thermostat until the choke is fully open. Do this after the engine is somewhat warm. If the engine doesn’t quit, you find the problem.

If the choke thermostat has rivets, drill them out and install screws.

Usually, running engines don’t vapor lock. Ok, maybe with current gasoline they do.

Modern gasoline has a lot more vapor pressure than they could get away with in 1968…This is what causes vapor-lock, not ethanol…You will probably end up installing an electric fuel pump back near the fuel tank which will usually cure this problem…Much will depend on how much you intend to drive this car…If it has a 428 4-barrel engine, I would be using the highest octane fuel you can find…Back in 1968, “High Test” gasoline was generally rated at 100 octane and that’s what that engine demanded…You can still buy 100 octane low-lead at your local airport after you fill out a “off the road use only” form…This gasoline is also very low vapor pressure so it won’t vapor-lock either…

I laugh at you Caddyman!

In 1992, Minnesota was the first state that allowed E10 as a motor fuel. Well? Those of us who had older vehicles started having problems with our older vehicles. And at first we couldn’t figure it out. Then we realized it was the ethanol in the gas that was causing corrosion to the rubber components, the castings to carbs, and vapor lock. Then we got pissed off.

Once we figured out what was happening, the MSRA, (look it up) filed a law suit against the state saying you can’t force people to use a motor fuel that causes damage to their personal property.

So now, when you take your 1968 Cobra Jet Ford to a gas station in Minnesota, you can get non-oxy gas.

Here’s the list.


First thing I’d do is have the fuel pressure tested, like others have said a weak fuel pump would do this. Given how new it is to you, having all the settings checked is also a good idea (timing/points, idle, mixture, etc.). And yes, you’ve got to run the highest octane you can find.

Gas line runs over engine and tubbing would get very hot

The first thing I would do is fix this. If this is some modification done by a prior owner, I would put it back the way the factory ran the line and with the OEM line type (did you mention this is a rubber fuel line?). I run quite a few original, carb’ed set ups that have hot rodded motors producing copius amounts of heat. They run fine on modern fuel even when idling in stop and go traffic.

Carmakers were terrible about putting gas lines near hot engine parts, somtimes running fuel lines a few inches away from exhaust manifolds and pipes. So it is a good idea to try and avoid hot areas by re-routing or insulating fuel lines. I’ve found the ‘Armaflex’ HVAC isulating tubing to be great for this.

Note that any fuel line relocation has to be done very carefully. Do it wrong, break a line while driving, INSTANT FIRE!

But the OP’s problems are extreme, I bet there’s a problem causing this, not just excess heat.

When this problem occurs again, check for spark. I’m not convinced that the problem is vapor lock. I think ok4450 has given you good advice that the problem may be a hot coil or condenser. If it truly is vapor lock, pour cool water over the fuel line a fuel pump and then try to restart the engine.

If those ideas don’t work, i can remember my 80 Bronco vapor lock cure.
I put a three nipple fuel filter in-line just before the carb. The third line is to return unused fuel to the tank. I ran a rubber hose all the way back to the filler neck and installed a nipple there. With the gas cap off you could clearly see fuel flowing from that return line.

This new return line kept fuel flowing and it would not sit around the engine area long enough to get too hot.
– problem solved –

I will throw my 2 cents worth of Ford problems in here. I had a good friend with a 65 Mustang. It would run great for about 5 miles. Then it would just shut down. His problem was a layer of crud floating in the tank would wick onto the fuel pick-up and cause it to run out of fuel .Wait for a couple minutes and it would take some turning but always start and drive about the same length of time again.
When yours died was it about the same mileage or just random? After 15 minutes, which I think is too short to “cool down” much did it start right back up or did you have a lot of cranking time on the starter before it ran?

Another idea - gas cap not venting? If it’s not, then it’ll pull a vacuum after a while, which a short stop would relieve.