RE: Breaking in DA 50
rcbill,
The DA50-R runs so well out of the box, that it should be run in on the plane, in the air. An engine gets much better cooling flying on a plane, than strapped to a bench, and the engine needs good cooling when running in. Yes, it should run a little rich during the run in, but too rich is not necessary. The low needle should just be so rich that you get a slight stumbling when throttling up, and high needle should just be set so that the engine doesn't surge at WOT. It is a bit of a pain to run these engines in, because you should stay away from 3D or full throttle as much as possible but you want to run as much fuel through it as fast as possible. Flying some IMAC sequences is a good way to get fuel through it fast. Don't make your full power uplines to long, have a fairly high idle in the air, run a 22x8 or 22x10 prop, not a paint stirrer like a Zinger. Run about 10 gallons of run in fuel (Lawnboy 33:1 mix) through it, you can lean the needles as you burn the fuel, you will feel and hear how the engine becomes more responsive and stronger, as you burn more fuel. The black mess out of the exhaust will also become less as the engine runs in. Fine tuning of the engine is best learned from a fellow modeler at your field, or perhaps you will pick up an ear and feel for it as you get to know the engine better.
DKjens