VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1928 National 4D Stalls and will not re-start

This car starts right up when cold, but after about five to ten minutes once it's warmed up it stalls and then won't restart until the engine is completely cold. We have tried all the usual solutions and nothing has worked. The only thing that I can think of now is that when we first worked on the engine we discovered that there was no thermostat and so we bought and installed a new one. I don't see how this could effect this kind of problem and I don't know if removing the thermostat would do any good but I'm out of ideas. Has anyone else out there had this kind of problem with the four cylinder engine?
HELP!

What are all the usual solutions??? Have you changed the ignition coil with a known good coil??? (i.e. a coil off another car that is running good.)Remember... If your using new parts..new just means your the first person to use it, it doesn't mean it is good. And old parts might be on a parts bench for a reason. Sounds like a coil heating up to me. Good luck.

You probably need to establish if you have spark and fuel, rather than jumping to all sorts of replacement parts. Do you know how to go about a diagnosis?

Regards
Al

Hi I had a similar problem many years ago, try running it without the hot air pipe into the carburettor.just pull out one end, If you have have a leak in the exhaust manifold to the exhaust pipe it will starve the engine of oxygen and it dies???? ether way it is a quick try.

Jim

Have you checked the valve lash clearance when its hot? Also could be vapor lock with the alcohol laced gas. Or may be a restriction in the gas line and the vacuum tank just runs out. Have you checked the vacuum tank vent restriction? When the vacuum tank is full of gas and the float toggles over it vents the vacuum to atmosphere so that the gas can gravity feed the carburetor. You should start with a mental list of potential problems and work from there. Good luck, make a posting when you find it for other people who may run into the same problem.

I have had similar experience, twice. First turned out to be the float in the vacuum tank was cracked and slowly sinking,and the second was the flapping valve in the bottom of the inside tank of the vacuum tank was sticking. Both allowed gas to be sucked through the intake vacuum line to the intake manifold, flooding the engine keeping it from starting. Letting the engine cool also allowed for enough evaporation so the engine started quickly when now lean enough. An easy diagnostic process is to disconnect and plug the vacuum line and see if the engine will start in a few turns on the gas in the float bowl.

We really need to find out if the problem is fuel or spark.

SPARK: Use a 12-volt battery as a power source for your timing light. Connect the timing light pickup to either the wire from the coil or to one spark plug. Start the engine, allow to run, press the button on the timing light and HOLD IT ON. When the engine dies, check to see if the timing light failed to record a flash just prior to the engine quitting.

FUEL: Connect the carburetor to a source of gas at a higher level that the carb. Start the engine, with a limited amount of gas in the source, run the engine till it quits. Is there any more fuel left in the container?

RESULTS: Depending on the results from the two tests, work backwards and see where the hiatus of continuity occurs.

+1 Black smoke out the tail pipe when it stalls? Sucking raw fuel through the vacuum line due to a fault in the vacuum tank. When it cools, the level in the vacuum tank drops a bit due to contraction/evaporation. Cycle repeats when started. When it happens, try disconnecting the vacuum line at the manifold and plugging it with your thumb while trying to start the motor. It may just fire right up.