Vibration in reverse (v-drive)

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.

Vibration in revearse is normal due to the turbulant water being directed towards the boat. However, its hard to say without actually experiencing what kind of vibration your feeling.

My Indmar 6L engine has a noticeable whistle noise at low forward speed and changes to a higher pitch when increasing speed. It then goes away when speeding up. I was told it has something to do with an air intake or something like that.

I was told the same thing about the intake whistle, but I've noticed it only happens when in gear. Doesn't happen if I disengage the transmission.

Me too, the whistling only happens when in gear (starts at approx 1200rpm).