Fly4fun,


This is a ringed ABN engine, with a parallel bore.
It needs a gentle, very rich, four-cycling initial break-in.
Gentler, richer and longer than described in the OS manual, is the way to go.

Do not dare to follow [link=http://www.rcuniverse.com/forum/m_1850473/anchors_1850473/mpage_1/key_break%252Din%252Ctapered%252Dbore/anchor/tm.htm#1850473]this RCU thread[/link], since it is designed for non-ringed, tapered-bore engines (which the OS.50SX is not), even if someone here mistakenly tells you to, as it will harm this engine.