Running-in the model diesel engine in 1 hour with rich fuel mix in 10 000 rpm and right propeller size is sufficient until the engine is run-in. "4-stroke" break-in is not necessary, and it is enough that much oil comes out of the exhaust port to remove metal particles that have worn away until the engine gets a perfect fit between the parts that are driven together. In your engine at 2 ccm need the propeller size 9/4 or 9/6.