1977 International 140

[mkr730]

My ignition will not kill the tractor. When switch is turned off coil is receiving power from alternator. What do I have wrong? When turning key on and off with tractor dead the power wire running to resistor on alternator is powering on and off just as it should. Please help.

 

[steve_in_mo]

You need a diode or a light bulb in line to stop the backfeed current from the alternator.
There are wiring diagrams on this site if you do a search for them.

 

[used red MN]

Did you change the alternator to an internally regulated one such as a Delco 10SI? Not real familiar with the 140 model, I think original for your tractor would have been an externally regulated (separate regulator) Delco 10DN. If you have installed a Delco 10SI internally regulated I am attaching a write up on that conversion. At the very end is a diagram that shows where the light or diode needs to be placed to solve your problem.
12 Volt alternator conversion

 

[CityBoy140]

My original 12 volt 140 has a generator not an alternator. I had to replace it with a remanufactured one after my tractor hitting a tree bent the shaft.