Let me say first that my Model T is by far easier to work on. Last year I had the wild idea to buy a 1939 Chrysler Royal. It does not like to start when it is hot and has set for 15-30 minutes after running fine. Does anyone on the forum have a Chrysler six about the same time period?
I ask on here because this is the best and most user friendly forum on the net!!
The first thing to find out is what you are losing after it heats up. Ignition or fuel. It's probably fuel but it's for you to determine. Unless you're talking about it not cranking properly when hot. More info would be needed to make a better decision about how to procede.
Old alloy pistons. Car will hardly crank until the pistons cool down and return to size. Had an Oldsmobile Rocket 88 with that problem. No matter how it was tuned, what fuel was used or how hot a battery and starter, the same problem.
Mike I put a small electric fuel pump on mine that bypasses the normal pump (with a check valve obtained from a local refrigeration supply house) I turn on the electric pump crank the engine then turn the electric pump off the check valve prevents the fuel from going back through the electric pump when it is off.
In this hot weather my 66f100 is harder to start.The carb is right above the hot exhaust manifold and I feel like it is the heat that is evaporating the fuel from the carb causing it to need to be turned over alot to refill the carb.
I had this problem for years on a '46 Che####t; turned out to be a bad ground connection caused by my overzealous restoration (too much paint!). Cleaned the connection area to bare metal, problem solved. Only took me about 4 years to figure it out!
If it is not an electrical problem, I bet the carburetor is percolating from excessive heat, and leaking fuel down into the engine after it is turned off, flooding the engine and making it hard to start. After you turn it off, pull off the air cleaner and put your ear to the the carb, and look into the throat and see if its flooding. If this is the cause, you simply get a phenolic plastic spacer to lift the carb away from the manifold and it should stop the problem. Ive ran into this problem on several old cars over the years. Some do it and some don't.
Thank you all for your comments. Here's what I have done. The carb is a remanufactured Carter. I put on a new fuel pump. I checked for weak ignition by pulling off the lead to the distributor while friend ran the starter. Got a good 1/4 inch long spark. New plugs, new wires. Cranks fine got or cold. By the way G.R. - beautiful Plymouth. I drove a 47 4-door in college back in the sixties and for several years after that.
I have suspected the Sisson Automatic Choke; I feel I need to put on a manual choke. My Model A buddy has a 1950 Plym that had a Sisson choke and was changed to manual years ago. My 47 Plym had a manual choke.
I want to move the Chrysler on down the road and stick to my T and my A. Not so finicky!
Many years ago I had a 1938 De Soto. It would run until it warmed up and then stop. After it cooled down It would start right up and run fine. It turned out to be the ignition coil. So when your car won't start, check for spark. If no spark, it might be your coil.
The most common reason a car won't start when hot, if the starter will turn it over, is flooding. You could have an internal leak in the down draft carburetor. That leak would allow fuel to drip down into the intake manifold and cause flooding. Try opening the throttle all the way and turn over the engine with the starter. After it spins a while it will usually start. Also check your choke. It should be wide open when starting a hot engine.
There is an excellent article August 2014 Street Rodder magazine titled "The Trouble With Ethanol" Mixing new fuel with old cars. It talks about the boiling point of gasoline, etc. but goes on to explain why perfectly good running cars don't want to start after driving them for awhile and some remedies. Ethanol just exacerbates the problem. It also address additives available.
If the choke is closing when the engine is hot your problem is flooding. If it's open as it should be when hot then it's something else.
I had the same problem back in the 70's with my 46 Dodge one ton. I was told the starter would pull too many amps and not enough left to start when hot. I would then flood it trying to start. I would pull the air cleaner off and fish a rag down the carb and soak as much gas as I could, by time I had done that it would be cool enough to start. Guess I had to do something instead of just sitting there waiting for it to cool down.
Somebody often parked a 1939 Chrysler Royal near my father's business. This was back in the early to mid fifties, and I remember how I thought that was such a beautiful car.
How old is the ignition coil?
One of my old cars would run great until it got hot, then would mystery shut down. The fuel pump was working, the carbs were neither flooded nor too lean; the distributor was fine, the grounds were clean and everything looked great. Everybody said, "Don't bother looking at the coil, they _NEVER_ go bad."
The coil and ballast were the culprits all along, especially the coil!
15 minutes of work, and problem solved! Something to consider.
I changed an engine once in a Corvair because it would not run under load. The replacement engine was just the same, until I changed the coil....
At least I ended up with 25% more hp, for just $45.
Well.....I've tested the ignition coil, but not under load and not when it was hot. I need to have a tested; a new coil is $268.00 because the one side of the ignition coil is a shielded cable out the back to the ignition switch. I have no idea how old the coil is.
I wonder......is there a way to use a meter while the car is hot and being started to test the voltage out of the coil.
PS Roar, you can own this car!!! It's for sale!!!
One way to test electrical components for heat related issues is to obtain a can of the compressed air that people use to clean computers. If you turn the can upside down and spray it on the suspected component, it will spray a very cold blast of propellant onto the part, instantly cooling it down. Don't blast it too long and don't get it on your skin. Once chilled, see if the problem is gone. This works on just about anything electrical and can be used carefully on a fuel system if you suspect vapor lock / percolation.
I believe that the Mopars of that era had spring-loaded heat riser valves in the exhaust manifold. Our '49 Plymouth did. If the heat riser is stuck closed, it will cause the carburetor to percolate when the engine is shut off hot. Hot starting is not a typical problem of the DPCD cars of that era. Wet starting is another matter
Interesting! My grandfather said that if a dog lifted it's leg on one of his 33 Plymouth's wheels, it wouldn't start!
There's a pesky ground wire that goes from the advance plate to the distributor body. If it's compromised, there's no ignition. Dad had a '39 Plymouth.... found out the hard way, on the road coming back from Wilmington, NC. ..... same trip he learned that smearing tobacco on the windshield will help keep somewhat clear in a rainstorm at speed when the wipers quit.
Bob, my first useful car was a '39 Plymouth business coupe. A full size mattress fit in the trunk. It was an excellent car, until it got sideswiped by an old lady in a big Olds. Her insurer, AAA, offered me $65 for it, and I asked $125 I had paid only months earlier. We settled on $85, and I kept the car.
That Mopar "Floating Power" let the fan hit the honeycomb radiator. I had it soldered up, and continued to drive it with the dented boilerplate rear fender until I got an MGTD.
Among the few cars in the Smithsonian four years ago was a '39 Plymouth coupe just like mine.
RD: Dad had the 4 dr sedan, inherited from his brother who was drafted.