No spark - coil voltage?

[mjdunn]

1939 Ford 6 volt. No spark. I have 6 volts going to the coil resistor and 2 volts going to the coil. What should I have coming out of the resistor? Could that be why it will not start?

[G.M.]

You should start with a fully charged battery, 6.4 The coil voltage
should be battery voltage with the points open and 3+ to 4.5 with
the points closed. You can jog the starter to open and close points
and tell by the voltage whether they are open or closed. If you have
battery voltage at the battery side of the ignition switch and it drops
at the switch side of the resistor you have a loose connection or dirty
switch. It won't start with less than 3 volts at the coil. G.M.

[mjdunn]

Thanks G.M. Good information. I charged the battery and everything is OK.

[rotorwrench]

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Since voltage is only dropped over the span of the resistor, that's how you have to check the drop. Measuring at the other end of the resistor to ground will always give you just a system voltage reading.