I had my engine rebuilt by a reputable machine shop; new pistons, rings, cam, etc. Also, I had insert bearings installed, instead of the Babbitt bearings. Starter & generator were rebuilt and a new battery installed. When I start it, it turns slowly, as if the battery was low – but it does start. A mechanic told me that was normal, until the engine gets broken in. Is that true? Also, any suggests as too how to break in the engine would be appreciated. Thanks. Bob