High pitch squeal at low RPM
 

As far as I can tell, it's only happening when in gear. If I run the boat out of water and rev it up a bit, nothing. When we take it out to the water, it sounds fine in neutral, but starts making a high pitch whine or squeal when it's idling forward. Sound goes away when we bring the rpms up a bit.

I will take a recording of it while we are out this weekend if that helps.

Boat is a 2003 Centurion Avalanche with 6.2L Black Scorpion.

That sounds like a drive shaft whine to me. Check to see if it does it when you come off plane, with the throttle in neutral, right before the boat stops, i.e., when the drive shaft is spinning slowest and coming to a stop.

Have you had the prop repaired?
I know our local prop shop said he had issues with the cnc props whistling at aroun1k-1500 if he sharpened the leading edge. But if he left it slightly dull it had no issues.

I just bought the boat 3 weeks ago, but they had recently replaced the prop before I bought it.

I wouldn't be revving it up out of the water...

Going to try spraying some WD40 in the shaft strut and see if it stops the whining for a bit. I read it's not a fix, but at least it lets me know if that's where it's coming from.

Using fake-a-lake. I've heard the dealer revving up boats quite often when they are working on something.

Sounds like a belt tension issue to me.

Yea I would say check the belt also. On my boat you tighten the belt by adjusting the altenator. Those bolts have loosened up before and sounded similar to your problem.

It's your prop shaft seal... Mine does it too.. Only at idle in gear.. Bet your's has the bronze coupling for the seal housing... Not a biggie if you can deal with the squeal.. If not, change the seal..

The belt seems pretty tight to me. I sprayed some belt dressing on it as well and made absolutely no difference. Wouldn't seem like it's a belt if it's quiet out of gear.

I'm leaning towards the prop shaft seal as Charlie mentioned.

I have a black scorpion also and mine does the same. I was told it was the vDrive but it could definitely be the seal since they are in the same area.

How is the engine temp? I had a high pitch squeal this weekend on my Black Scorpion and it turned out to be a toasted impeller and it actually started melting the impeller housing. As far as tightening the belt on a Black Scorpion there's a 5/16 nut and lock nut on the pulley just above the impeller that you adjust the tension for the belt.

Temp seems to be fine. Can't remember what the number actually was, but it was right in the middle of the gauge every time I looked at it. Almost certain it's something to do with the Drive or Seal being that it only happens when in gear.

Thanks for all the suggestions. Probably going to just deal with it until the end of boating season.

I know this is an old thread, but I'm having this exact issue what you described on my 2011 Axis A20. It started off as only whining as I come off plane, after driving it for a while, then it started to whine at low rpm while idling in forward gear.
Pillywakeboarder, Can you please elaborate a little more about it? Is there anything I should check or test? If I can deal with the sound, any potential for getting stranded or damaging other components? Maybe you could point me in a direction?

Thanks :)