I have the same boat and was surprised by the noise also. What I eventually found that quieted the motor was one of the air intake hoses had come off the engine. It just wasn't fastened tight, but without jiggling the hose you couldn't tell it was off. Once I hooked it up I saw both a performance and noise improvement.
There are also several other posts about noise reduction here. Do a search for "loud" and/or "noise" and you will get them, but I didn't see a silver bullet to solve the problem.
- jorous likes this