01-01-2019, 02:53 PM
Hi Andy
A standard coil will draw about 4 Amps with the contact breakers closed. When the engine is running it draws this about 50% of the time, so the average current is nearer 2 Amps. You should measure about 6 volts between the "Switch" side of the coil and ground, whether the coil is drawing current or not. I suggest that with a points type distributor fitted and the cap removed, you turn the engine over slowly on the crank until you see the points are closed. Then turn on the ignition and measure the voltage to ground at the coil "Switch" terminal and the Coil "CB" terminal. These should be about 6 volts and a small fraction of a volt respectively.
I suspect from your description that you have a high resistance / bad connection somewhere in the LT side of the ignition system. The ignition switch is one possible culprit.
A standard coil will draw about 4 Amps with the contact breakers closed. When the engine is running it draws this about 50% of the time, so the average current is nearer 2 Amps. You should measure about 6 volts between the "Switch" side of the coil and ground, whether the coil is drawing current or not. I suggest that with a points type distributor fitted and the cap removed, you turn the engine over slowly on the crank until you see the points are closed. Then turn on the ignition and measure the voltage to ground at the coil "Switch" terminal and the Coil "CB" terminal. These should be about 6 volts and a small fraction of a volt respectively.
I suspect from your description that you have a high resistance / bad connection somewhere in the LT side of the ignition system. The ignition switch is one possible culprit.