TO20 will not turn over no voltage with switch on

Hello,

I just purchased a 50-51 TO20. Was running fine. Went out to start it and would not turn over. When ignition switch is off I have 4.5 volts (6 volt system). When I turn on the switch voltage goes to 0. disconnected the coil no voltage issue so replaced today. still having voltage issue. When I separate the points voltage issue goes away. Is it the points or the coil? or is there something else that I'm not thinking of?

Is there a solenoid in the system. If so you may have the key switch incorrectly wired. The tractor should turn over when the normal shifter
start is used.

On a solenoid key there is a run position and start position. The start post allows power to the coil and solenoid. If it is original I would check
your battery cables for the issue

There is no key switch just a toggle. power from switch goes to coil and control box.

Sounds like either a dead/bad battery, or a dirty/loose connection.

First, a battery showing 4.5 volts is discharged, or bad. It should show up around 6.1 to 6.3 volts when sufficiently charged. When using a 6 volt system, everything must be right in order for it to work, clean cables, large cables, healthy battery, healthy starter, well tuned engine.

Once the battery is charged, if still having a problem, give this a try:

With the ignition on and the points closed, or some other load on the system, like lights, etc., begin testing across the battery posts (not the cable ends, the actual lead posts. If you have no or low voltage, the battery is bad.

If good voltage there, start systematically moving one lead at a time, noting the results with each move. Example, leave one test lead on the positive post, move the other lead to the cable clamp, note the voltage. Then move the lead that was on the positive post to the positive cable clamp, note the voltage. Keep moving one lead at a time as you work your way through the electrical system. When the voltage drops, you have found the problem.

Some things to look for along the way are corroded or rusty connections, loose connections, burned or heat discolored connections, or any connection generating heat. The ground connection to the sheet metal is a common problem, too small battery cables (automotive cables will not work, need to be size 0 or 00 to carry high amperage of a 6v system), ignition switch exposed to weather, under dash connections exposed to weather, 60+ year old wiring, mouse damage, and non functioning charging system.

Thank you for the info. I have never dealt with a 6 volt system so any info is great. I will charge the battery and go from there.