My lawnmower is spitting out dark oil from side, it wont start, does that mean it needs oil change?

not a change of oil. source of oil needs to be found .can be a failed gasket ? or is it from exhaust itself? if a simple gasket failed it can be replaced if its something more serious such as a blown head gasket can be repaired but more expensive if a cracked block ? cheaper to get a new machine.