you've got a thru-hub exhaust if you'll find exhaust holes about the engine gearcase within the prop shaft. Non thru-hub is solid within the prop hub. Non Thru-hub Exhaust
If your boat is managing sluggish, jogging https://inesirjm824007.bloggerswise.com/36412822/the-2-minute-rule-for-yamaha-4-stroke-outboard-motors-for-sale