The guy that started that "rumor was Clarence Lee, Dave Geirke and the manufacturers among others.

RCpilot,

And which manufacturer says to run an ABC engine rich at anytime? Not OS, Enya or any of the other major manufacturers. I have had three OS120 Surpasses, two FS120's and dozens of other OS four cycles and two cycles and broke them in according to manufacturers instructions and EVERY SINGLE ONE was/is a great running engine.