Welcome to the forum and congrats on the orange tractor.
Well you may have a few problems with a tractor but which one has none???
Anyway the only way to get oil in the starter that I can think of is to have a rear crankshaft seal leaking or the transmission front seal leaking.
How are your fluid levels?
MAKE SURE TO KEEP THE RADIATOR FULL AT ALL TIMES OR YOU WILL BLOW A CYLINDER HEAD ! ! ! ! !
There is no water pump or thermstat in that setup you know.