You have a thru-hub exhaust if you will discover exhaust holes over the engine gearcase across the prop shaft. Non thru-hub is good throughout the prop hub. Non Thru-hub Exhaust
Another Repeated challenge with https://umarsowl455387.blogsuperapp.com/30200638/5-tips-about-yamaha-4-stroke-outboard-motors-for-sale-you-can-use-today