40 Ford won't start when after running

[Fargo Mike]

1940 Ford with stock 85 HP flathead. Just installed a Skip Haney rebuilt coil hopping it would correct the restart after warm start problem. What is our next steps??? Thanks for your help. fargomike

[Kube]

Look down the throat of the carburetor immediately when it won't restart. Pump the throttle by hand. See any fuel coming from the jets? If so, your next step would be to replace the condenser with a KNOWN good one.

[mike42]

Fargo.....I had the same problem after Skip reworked my coil. I did as Kube said, but then someone suggested a condenser. I called Skip and he said to go with a NAPA Echlin IH-200 as he has never had a problem with them. No probs after that. $ 10

Good luck.....Mike

[Joe KCMO]

I have had the same problem with my 39 for the past several years. I replaced everything except the motor. I think I have finally solved the problem. It was the stock coil resistor. When cold supplied 2.9 volts to the coil. Once the resistor warmed up, the resistance went up and the voltage dropped closer to 2 volts stalled and would not start. After it cooled down the voltage went back up to 2.9 volts and started.

After a lot of experimental work, my solution was to replace the original wire resistor again ( many new old style resistors were bought and tried) except this time with a new solid state wire wound heat sink power resistor. The resistance is constant at any temperature and delivers about 4 volts. No more problem.

Not a solution for a 100 point show car. But for a third of the price of crapy original resistor at $5 and solves the problem. My engine always starts and even runs better with the higher voltage.

I replaced the carburetor, the distributor, the coil, the resistor, the points, the caps, the rotor and the wires. The final solution was the original equipment resistor which increases resistance when hot. The voltage is good enough to keep the engine running (barely) but would not start after the resistor warmed up. For $5, it is worth a try. Take the voltage readings when it will not start and if you find reduced voltage (less than 3 volts), I think you have found your problem.

Every car will be a little different due to parts being switched over the years. Coils have different resistance as does the wiring in the car. Take your voltage readings and you will find your problem.

[trainguy]

Joe ,where did you buy the "solid state resistor"Phil

[Joe KCMO]

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Originally Posted by trainguy

Joe ,where did you buy the "solid state resistor"Phil

Newark (Name of the company)

Attached is the first page of the catalog listing. Determine the voltage needed at coil and buy appropriate resistor. 50 watts rating needed.

[dewickt]

Same problem with my 35 Woody, I used to reach under the dash and short the resistor with a coin while cranking and it would start. I finally got a good replacement (possibly OEM) resistor and problem of hot start went away.

[trainguy]

My 41 coupe had a push button that jumped across the resistor for hot starts.Don't need it since I installed a skips coil and good condenser.

[Joe KCMO]

I use coils I have bought on Ebay for $5 and $10 and they work just fine with good resistor. Just saying. The three engines I use these resistors run better and stall less with the extra voltage. I will have my ford script coil rebuilt for longevity and show.

[FlatheadTed]

This is another example of what could be confused as vapor lock

[BillM]

Coil or ignition resistors; also called ballast resistors are designed to be low resistance when cold and a higher resistance when hot. If the coil resistance is not matched to the ballast resistor, there may be too much resistance when hot. The constant resistance of a standard resistor may drop too much voltage when cold, which could cause cold start problems. It's a balancing act. I think the best solution is to use the proper ballast to match the coil.

[Kube]

You asked what the next best thing to try was... you got a couple of good replies in my opinion. You need to eliminate things. The first of course is to see if you have fuel. if you do, the easiest and most likely culprit is the condenser. If that doesn't do the trick, as others have suggested, check the voltage. Those resisters do become faulty. However, that is a much less common dilemma than the condenser.
One other thing that can cause this symptom... the ignition switch. This would be way down my list of "probables", however, I've seen this cause your problem. A quick check is to reach around the switch and see if it is hot to the touch. If it is, it's bad, causing high resistance in the circuit.
The repop switches are not worth spit. NOS are often found on eBay.

[Brendan]

check you battery connections. my 36 just would not start. it would crank over fine but not start. the starter switch had started smoking from louse connections. I tightened them up and that fixed the trouble