only thing I might add, is do this twice
be sure to let all the oil drain out good, not a quicky, I am in a hurry oil change.
use a new filter each time
run the tractor until its at operating temp then drain the oil again.
that gas in the crankcase will start to clean the old crud off the insides of the engine and then it will/can stop up oil lines
then you could have real problems, scored bearings etc:
good luck and as said before, learn to turn off that gas shutoff valve each time, you just can not trust the old carb floats.
remember: old dogs can be taught new tricks, if it cost them enough!!!!!!!!
believe me I have had to drain the carb a few times when I forgot to cut gas off.
had to get up from my lazy boy and go back out to tractor shed and double check to insure I cut off fuel valve.
I need to put up a big sign in the back side of my tool shed, on the wall right in front of where I park the old tractor
CUT OFF FUEL VALVE