I hope someone can help me with this, I have a 2002 yamaha 115 4 stroke and this week i was running and I hit a piece of wood not hard but i felt it hit. The engine looks fine and runs great but now at low idle it is shaking and vibrating the boat, I checked the prop and it appears perfect?? I assumed I bent it or something. Can anyone help me with this? It runs fine and seems fine except the boat is vibrating at low power and I can only assume it was from the hit? It is on an 18 foot Mckee craft center consol.