Wait, the OS engine is a ringed engine.... Nobody has made mention of this!!!!! You CAN run a RINGED engine rich... I almost exclusively fly OS engines and I have always broke them in the way OS recommends, all my engines are hand started, and all usually start on the first flip. The engines that you do not run in a rich 4 stroke manner are the non-ringed ABC engines like a dub jett... but the jett engines and the OS ringed engines are two different beast all together....I can explain further if interested, but take it from an OS man, the OS break-in is just fine.