Still not able to get my 1940 Ford 9N running it was converted to 12 volts with electronic ignition, including a coil like in a car and everything was working very good. The starter switch stopped working when pressing the button on the floor so I did replace the push start switch and the new switch still does not turn the engine?? to me I don't think this is the problem the fact the new switch does the same.
If I bypass the switch with booster cable at the battery ( + at the starter and + battery than - at battery and the other - on touching the frame I am able to get the engine turning and trying to start but only if I keep the cables on with the starter turning as soon I remove my - to the frame the engine stop!
I took some voltage measurements if the key is OFF voltage at the yellow wire going to the alternator is about 13 volts with the key ON it drop to about 2 volts, now at the coil if key OFF I do get about 2 volts and with the key ON 0 volt???
your help is appreciated