how much voltage should the coil have?
 

I am still looking for a weak ignition or timing advance problem on my truck. I replaced the coil with no improvement. just to be curious I tested the voltage on the coil. I am getting 12 volts to the coil. but when I test the voltage between the + and - sides I only get about 6 volts likewise if I stick the tester into the cap (where the wire goes) and put the other wire to ground, I only get 6 volts. is this normal. or should it send 12 volts through.

p.s. when the truck is sitting with the key but not running the coil will start to heat up. Is this a possible wiring problem or is this normal because the coil is ruducing the voltage down to 6.

thanks again
Brian

how much voltage should the coil have?
 

Hi Brian, that sounds about right but I curious how you got that 12 volt measurement. When you’re testing the points need to be closed. It they are open then you will get 12 volts to the coil because there is no current flow thus no voltage drops. With the points closed it completes the circuit and you should measure a little over 1/2 of the battery voltage from the + terminal of the coil to ground. From the – side of the coil to ground you should see no more than 1/2 volt, the lower the better.

Yes the coil will heat up if the points are closed because it is on all the time.

Barry

how much voltage should the coil have?