You can see debris was impacted in the softer bearing material. This material is what damaged the Journals IMO. Still we may never figure out what practices were carried out wrong but now we know the Block is full of this material and needs pressure washing to remove all the contaminants possible. Yamaha 4 Stroke Outboards are the most sensitive to clearances of all the engines I have read about. Since I only Build 2 Stroke Outboards and Hot Rod Engines I have no direct experience with 4 Stroke Outboard internal engineering. Yamaha tolerances are extremely demanding unlike automobile engines so very strict adherence to clearance protocols is necessary or this repair will be short lived IMO.