I have been watching you tube channels like Vice Grip Garage or Morske repair. They start up cars that haven't been running for year. Vice Grip Garage has a few videos starting old tractors that haven't run for years, often with overheating problems.
I have had a dirty radiator cause heating on my TS-1610. Still running a little hot on my TS-1610 after running for a long time.
Could be anything from the radiator cap, loose belt to the fan, water pump with bad impeller, or rust/clogged water passages. Also good to know if your oil pressure is good.
Not sure if these have a thermostat. Sometimes they try putting in a thermostat if it is missing or removing the thermostat if it is there.
Some type of thermocouple or measurement gauge to know the actual temperature would be helpful if your tractor doesn't have a temperature gauge on the dash.