RE: Engine Break-In
PKH,
I broke in my OS50SX with two tanks on the ground, alternating between very rich and just breaking in to two stroking as per the instructions supplied, then flew it for about 8 tanks running rich before leaning it out to peak and then rich a few clicks. About 20 tanks later I started having problems with it, it wouldnt rev hard, woudltn hold peak in flight after about 5 min flying and the oil from exhaust was always very dark during those tanks. I then went to a smaller prop and ran it quite rich for another 15 or so tanks and its come good, back the original 11x6 prop and it pulls around 12000rpm on the ground. I would suggest running it about 1/2 to a full turn rich for at least 20 tanks BEFORE trying to get absolute peak RPM from it in flight. It appears to me and others at my club that it likes a richer mix for quite a while to seat the ring in really well then it will hold peak power for the duration of flight.
Everyone has different ideas but thats how Id do it if I had another to break in.