Push stop button - place spanner over solenoid to start
Love old engines - not economical in any way, but they do run with a good bodge.
Go for an old Dia Brownn if you can get one. Got a 990 selectomatic here with a little front loader, great for lifting muck and stuff thats not heavy - the only tractor that still starts off the key, the only tractor you can leave the ignition on and it doesnt run the battery out as it has no lights at all, one way hydraulic output thingy, pto, solid gears. It may have no brakes, seat mad of fence posts, bald tires, loads of rust but she is worth the weight in gold (turn of phrase obviously lol)
Its got a roll bar on it too, but in all honesty I would ignore the advice of 'grip the wheel and stay on vehicle' - I always 'grip my pant bottoms and walk to toilet' whenever its felt like turning.
Alot of the decent running old stuff gets exported now
Baz