I bought a boat with a 2006 Honda 90 hp. At idle the lower unit makes noise. Goes away after throttling up. I've checked lower unit oil and it's good. Previous boat I owned had a 1999 100 hp yamaha, I had a mechanic that tuned it for me, tell me the motor will have a little noise in lower unit noticeable when run out of water. It did. But I didn't notice it when in the water. Used the boat a lot with no problems. Is this honda the same way? Im hesitant to go out if it shouldn't have a little noise also.