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Thank you for the feedback.If the other cylinders are measured to be in spec then boring one is acceptable I believe.
My concern is that the oversized piston might cause an out of balance issue. Maybe I am overthinking it.I've done that on a 115 Yamaha. Ran great with no problems after that. Then Hurricane Matthew came to Savannah and dropped a 60' oak tree perfectly lengthwise on top of my boat! That was the end of that boat! One of the trailer wheels shot all the way across my backyard an the other one Put a perfectly round hole in the next door neighbors privacy fence and ended up in the middle of his back yard. Insurace didn't cover it because the insurance I had only covered the boat in the water and on the road. It wasn't covered by homeowners insurance because it wasn't "declared" to them that I had a boat parked in my yard. Sucks still today. But the boat I replaced it with also has a 115 Yamaha on it. Great motors!