ORIGINAL: fredscz
Do a search and you will find that "BAX" the tower hobbies/futaba/os representative has posted more than once that the "four cycling" part of the break-in on the FX/AX non-ringed engines is WRONG!
This is the factory rep saying the factory manual is wrong! The four-cycling does not let the engine come up to proper operating temperature and causes premature piston/liner wear and a lot of extra stress on the rod.
I just recently witnessed a brand new 46AX on a new trainer started and flown rich to "break it in". The engine never did run right and the owner bad-mouthed OS engines as being no good when it was the engine tuner at fault.
FB
I broke mine in according the manual, and it runs great and has been running for a long time! So what does that prove?
As to a rep coming on RCU and saying the O.S. manual is WRONG, I wonder why O.S. didn't revise the manual. Seems like a poor business model to publish a manual with a break-in method that you know is going to ruin the engine. I bet their engines would be about $10 a piece if they didn't have to keep replacing all the ones that are broken in in accordance with the supplied manual.