I have trouble with hot starts

Question:

Mr. Richardson, Love your column; it is the first item I read. I have a 1947 Packard Clipper 2115 and am really having trouble restarting her when hot. It starts fine when cold and will restart after an hour of cooling off.

I have had tons of conflicting advice. The timing is OK, and it’s a recently rebuilt engine. I would like to try your “newer starter” with a lot more power. My car should be very similar to your 110. I would really appreciate your advice on this matter. Keep writing. We see things eye to eye.

Answer:

The starter on my 1940 110 was a quite small Autolite model MZ-748 that put out only 11 pounds of torque. It was also commonly used on Willys four-cylinder vehicles and tractors and was barely adequate for the job of turning over that big 245-cubic-inch six. However, I once had a post war 1946 Packard Clipper Six and it came with a better starter than my 1940 110 to begin with.

Part of the problem with the early starters is that only two of the four poles in it were wound. Later starters put out 11-18 pounds and many had all four poles wound, thus giving them more torque. There is also no problem with swapping out a later Packard starter for an earlier one because any of the junior series starters will fit from 1935-54. The later Custom Eight’s starter is different though and not what you want.

That being said, I doubt that the starter is your problem. On a post war Packard it is more likely to be one of a number of other things; the first being a vacuum leak because of a loose manifold or a faulty vacuum line to your windshield wipers or vacuum advance.

I would also check the sparkplug wires, sparkplugs, and engine timing. And if your engine has a fuel filter I would check it too, along with the air filter, to make sure they are clean. Also, make sure the choke linkage is not binding and is adjusted correctly so the choke is open when the engine is hot. Don’t oil it, though, because the oil can get hot and burn and cause the choke to stick.

Also, when you try to start the car when hot, do not pump the throttle. That will only flood the engine. Instead, first try to start it with no throttle input at all, and then try putting the throttle to the floor and keeping it there while engaging the starter until the engine starts.

Your problem may well be vapor lock too, which happens when heat vaporizes the fuel in the fuel pump, fuel line or carburetor. Isolating and insulating the fuel line can help that, as can installing a heat shield over the fuel pump. You will also want to make sure that the heat-resistant block between the carburetor and the manifold is good. However, the best way to cope with vapor lock problems on hot days is to install an electric fuel pump.

You can mount it at the back, underneath on the chassis near the tank so it won’t be seen, and then hook up an under-dash toggle switch to turn it on when required. An electric fuel pump will also help the engine start quickly if the car has been sitting for a long time, because an engine has to turn over a number of times to get fuel up to the carb with just a mechanical pump. You would generally only use the pump to start the car, and then turn off the electric pump and run it off of the mechanical pump the rest of the time unless you experience a vapor lock problem on a hot day.

If none of the above helps, I would take the carb apart and make sure the accelerator pump is in good shape, the needle valve is not sticking, the float level is adjusted correctly, and that everything is working smoothly. And finally, I would readjust the idle mixture screws and set the idle to the specs in your shop manual.