So I also made a thread about a whistle/squeel sound in forward at around 1000-1600 RPM; goes away any higher. http://wakeworld.com/forum/showthread.php?t=799389
Not sure if these problems are related, but I'm also getting a pretty bad vibration in reverse. So at an idle reverse, it's fine. Only happens when I rev it up a bit, and then it's a pretty strong vibration.
I've heard it could be the prop, or even the rudder fluttering. The prop was just replaced by the previous owner when I bought it, and I haven't noticed any chips or dings. I'm just wondering if my two issues could be related.