VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 car won't start

He llo from Australia,
I need help desperately and I hope someone can come up with the right advice.
I have 1948 Chev which has a problem with starting when hot. Initial starting is not a problem, however after I drive for about half an hour or more and I park it for longer than 10 minutes, it will not start again until it has cooled downto less than 60 dgrees F. It will start and run beautifully again. I have replaced the fuel pump, the coil as I was told that therein lies my problem, but alas that was just garbage advice.
When it is hot it will start and run for about 10-15 seconds and just die as though it was being starved of petrol. My thoughts are that there is a vapor lock somewhere in the line but if that is the case I have no idea how to solve it.
I had to wait for 3 hours last Sunday before I could start it again and with summer approaching the problem will get worse.
Can someone please help me. BTW, the car does not overheat when it is running normally, usually stays about 75-80 degrees F. but rises dramatically when it stops.
Look forward to your thoughts.
Ron

First, it may be flooding. Try mashing the accelerator pedal full open when starting it. That may help.

Second, check your feed line to carb to make sure it isn't getting too hot.

Third the needle valve in the carb may not be opening and closing as it should.

Fourth, check the choke butterfly in the top neck of the carb.

Fifth, check points and timing. Long shot.

That's about all I can think of right now.

Good luck with it,

Charlie

BTW: I think you meant to say about 175-180 F.

I have had some sucess with opening the hood for a few minutes when stopping. The heat can escape instead of being traped under the hood. Grant

Grant,

That is a helpful suggestion. That is a good way to disseminate heat. Works for some old cars real well. Even on a 41, but we 41ers can't do that because with the hood up it makes it look too much like a 38. Right embarrassing. You know.

Charlie

Aussieron...It sounds to me that you may have vapor lock (like you said).
I think that the gas in the float bowl may be evaporating due to the heat off your exhaust/intake manifold.
Do you have the insulator that is under your carburetor?? (That is the thing that looks like a stack of gaskets, about 1 inch+ high) That is there to keep that from happening.
If you are missing that insulator it is available from most of the dealers in vintage Chevy parts.....Good Luck ED

Buddy bought a 51 stock Chevy pickup. It started when cold, but wouldn't start when hot, wouldn't hardly turn over. Replaced starter generator, carb and of course normal tune up items. I mentioned it to a mechanic buddy and he said it sounded like it was to far advanced. He retarded it just a little and guess what, it starts when it is hot now. Double check your timing.

If you are timing by "ear", retard the timing until you get a favorable setting that the car will start easily. Slowly advance the timing until the engine starts to "kick back", then retard to where it turns over easily.

Thank you one and all. There is a lot here to look at and try. I will certainly give everything a go and will let you know the result. With regards the insulator under the carby, mine does have one although it does look a bit ratty. It still should work as intended though.
Maybe a week before I can test out the car again so will be back to you after that.
Thanks again everyone.
Ron

mmm,mustard biscuit,mmm put some gas in it....