you do have a thru-hub exhaust if you will find exhaust holes within the engine gearcase within the prop shaft. Non thru-hub is reliable across the prop hub. Non Thru-hub Exhaust What's more, it retains your boat safe https://zaynabooia916526.howeweb.com/30263844/how-much-you-need-to-expect-you-ll-pay-for-a-good-yamaha-outboard-motor-for-sale