If you have not pulled it apart, don't just yet. Put it on a stand and try to run it providing the bearings don't feel like 50 grit sand paper. If it had YS type fuel 20/20 mix run in it you may find it's just fine. Do not put petrol based oils (after run or other) in this engine as the pump parts are silicone and will swell causing all sorts of problems. If you feel the need to use some type of after run oil, use a synthetic 2 cycle oil sparingly.