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Black_Diamond

In the days of old, breaking in good before using full synthetic was needed, as the machined surfaces needed to seat before adding in oil that lubricated 'too well'.  Engines of current technology are built far better on surface finishes of the machined parts and tolerance control and do not need all that time to 'break in'.  Look at the new cars that are full synthetic right from the factory these days.  A lot of the break-in for a boat is the drives too, not just the engine.  Be smart, follow the manual when they are new to CYA while under warranty.