I have a Magnum 46 xl engine on my J3 cub. I ran the engine twice, once for initial break-in followed by a short test flight. During the test the engine died of fuel starvation (muffler came loose) and landed w/ prop windmilling. This was back in 1999, I haven't ran the engine since. I would like to get back into the hobby soon, I inspected the engine and found it to feel somewhat gummy while turning by hand. Additionally the carburetor butterfly is now difficult to move. What are the appropriate steps I need to take to return this engine to serviceable condition? It seemed normal after the flight, I believe the problem is improper storage for 9 years.