If you overfill the oil it can get sucked thru the AOS & get into the cylinders.
Remove all the sparkplugs & try to start the engine. It won't start but any oil in the cylinders will be forced out. Trying to start the engine with oil in a cylinder can bend a rod or break the cylinder wall. Once you have forced all the oil out inspect the sparkplugs for damage or oil, reinstall good plugs & try to start. Be gentle & cautious as the engine may be damaged & it could get worse. The engine can run with a slightly bent rod but not for long!
