guess i am just old school, maybe it comes from always having old used equipment,
but, before i try to start the old fergy, 1957, TO35 I always check the coolant, oil and fuel levels, 1/2 the time i also check the hyd/diff fluid level.
then turn gas valve on and fire it up.
the carb will leak fuel sometimes, if you leave the gas shutoff valve open.
it can drain your tank, but you would know if that happen, as you will have a strong gas smell in the storage shed.
good luck and always check your fuel level before starting up the old tractor, this practice will serve you well over the years, if you own an old fergy.