Is it the NT or the latest version NX? I had a 46 NT that came in my Hangar 9 plug and play Piper Cub that wouldn't run right no matter what I did. I sent it back to Horizon under warranty and they couldn't make it run right either. They said they replaced almost every part on the engine and still no luck. They sent me a brand new Evolution 46 NX as a replacement as the NT was discontinued and the NX was the new version. So far the new engine runs great and is very strong. I'm happy with it so far but it doesn't have a lot of time on it either.