Easytiger,

You need to be a little more specific about which OS46 DF engine you are referring to. The "older" OS 46 VFDF is an infinitely more reliable engine than any of the K&B 7.5s (both FI or RI) with equivalent output power, and the newer OS 46VXDF will blow any K&B 7.5 out of the water in both power (the VX has 25% more output power than the older VRDF) and reliability.

Regards,

Peter