I started initial break-in on my OS 30s CL engine on my test stand. Followed the OS suggestions in the manual. I bought the engine NIB from a guy, so I believe it is stock.
Some observations:
Initial break-in
9-5 prop
5 nitro/29 all castor fuel
Ran 4-cycle rich, 6 two-minute runs allowing to cool between runs
No muffler during break-in period
Not knowing a good needle setting I initially tried 3 turns. Engine would only run briefly off of the initial prime, then quit. So not enough fuel. It took 5.5 turns on the needle to get it to run at a healthy 4 cycle. Around 9,000 rpm
I will run a few more times the same way, then proceed w/ more runs, but start to lean out on progressive runs.
Engine ran consistent on all runs. A little hard to start initially but started easier on each run.
After break-in, I plan to try the engine out on a SIG Banshee. I currently have an OS 40FP on my Banshee. Flies OK, but the 40 is really too much engine (and heavier). If the 30s flies better, will use it. If not, go back to the 40.
One other thing. The engine came w/ what looks to be a long reach plug which I used. Seemed to be fine. The plug has no markings on it, so don't know if it is an OS plug. The owner's manual mentions an OS 7 plug. I have no idea if the OS 7 is a long reach plug. The OS 7 is a medium-hot heat range design per OS.