I would also check the blow by filter and screen, they may be plug as a result of over filling with oil, if so can cause the engine to lose vacuum and push oil out the exhaust. Just trace the blow by tube from the back of the carb to the engine just under the flywheel, you will have to remove the shroud and filter housing in order to get to it, you may have to remove the flywheel to remove the blow by cover, in order to get to the filter and screen.
Might remove the air filter first and see if it looks oily inside like oil is blowing up thru crankcase vent tube.
Have a good day....!