Take the back cover off (4 screws) and inspect inside of crankcase for dirt or debris. Clean oil and fuel residue should be what you see, not dirt from the crash. Clean if needed, check and clean carb throat and barrel. Make sure the small air bleed hole in the front of the carb is clear. Clean outside with Dawn "Power Dissolver" or Dawn "grill Cleaner", same product with different labels.Lube engine with after run oil. Mount engine in test stand and test run it. If you don't have a test stand, put one on your shopping list and just install in new plane and test run it there. Oh, also test the glo plug as they sometimes don't like impacts. Replace if questionable. Make sure the crankshaft isn't bent. Now, after readying the new plane and cleaning, inspecting, and testing the engine this is where you find a new instructor that has better judgement. Even If you can solo yourself, get a good helper to mentor the test flight on the new plane so that it lasts for a while. All "common sense" stuff. Good luck.