Your engine never needed any break in time, they should be reliable from the first minute of running. Break in will develop the compression some but the engine should not need bench running and in fact most experts think that bench running can do more harm than good.

If it's stopping in flight I'd say be sure it has adequate cooling, that's the main culprit in dead sticks as long as everything mechanical is good.

Also check the pickup line in your tank, running good for 2-3 minutes can be a sign your pickup line is not working properly and you are sucking air after the tank gets down below full.

TF