The OS 46SF is not currently being produced. It is from 10 - 15 years ago. It is a very fine - likable engine that is easy to start and adjust. It doesn't have as much all out power as the FX version. It is about 400 rpm less with the same prop.

The OS 46 FX is current production. They are a fine engine too. However, they sometimes have a quality problem with the cylinder peeling. This problem is variable. You may get one that runs forever and is the greatest engine ever built. But you could also have cylinder failure after failure.

Good luck,

Jim