In Reply to: 1940 Ford 9N starter switch ???? posted by Serge on March 14, 2018 at 18:44:36:
That is a mechanical switch so the only electrical components to worry about are the contacts.
They are designed to carry the current of a 6 volt system.
Since a 12 volt starter pulls about half the current of a 6 volt system the switch should work fine.
The exception to this would be if you are still using the 6 volt starter. Then the current flow would be considerable higher and might exceed the ratings of the switch.
However my 860 has been converted to 12 volts and the starter solenoid has never given trouble.
How does you tractor start. Easy or do you have to grind on the starter? Grinding would be hard on the starter switch also.