Strange squeal when dropping motor to idle

Well, I'm sure i won't be able to describe this accurately, but here goes;

Whenever I'm running the engine (rpm's don't matter, temp doesn't really matter) and drop it back down to full idle, the motor comes down to idle like it should, then i hear the strangest noise that is basically a whine that starts high and lowers in pitch, then goes away. Some are longer than others, but I have been back there trying to find the source and have been completely unable to.

For some back troubleshooting history that may be relevant, the last time this started happening coincided with a faulty water pump, and went away when the pump was replaced. It just recently started happening again, could I have possibly not put my impeller in correctly?


Any help is greatly appreciated, thanks in advance guys!

Tony, what type of boat is it? my previous boat was an I/O with a power steering pump... i went almost a whole summer suffering from the same sound and when i had my mechanic working on something else he mentioned that he topped off my power steering pump... the next time out and from then on there was no squeeling.

Sorry, I suppose that would have been valuable information to include

It's an 02 MB B-52 (inboard), so it's just the steering cable/rudder, no ps pump (I could be wrong?)

Thanks though! I hope it's something as simple as that!

could be the packing if it's not dripless and it's too tight to liquid cool.

Also could be a small piece of debris in your impeller.

I had a similar issue. My situation could be totlly different but, turned out that the key after strating would not quite flip back all the way and was causing the the starter to be engaged slightly. It was intermittent. Jigged the key and it would go away. Changed the key and it hasn't happened again. Only happened at idle.

Could be something as simple as a loose belt, make sure you check those.

Yeah, I was going to say check your belts first. Also, I had a sound similiar to that. It was a whistling sound that only came after being at wide open throttle and then pulling back on the throttle arm to slow down.

Turns out the cause of my sound was a slight leak in the intake manifold.

I have the EXACT same problem with my Supra. I spoke to a Supra mechanic and explained it just as you have here. Since the sound is very intermitten, meaning it doesn't happen every time I go out, he said he thought it was probably just water in the bilge splashing on the belts.

He said that if water gets on a belt it will cause a sound similar to what we are hearing. I am hoping that this is all it is. If you find something different please post it up.

I've checked all of my fluids and hoses and can't seem to find anything wrong. I hope my mechanic is right?

Thanks all, great info...I'll definitely post up if i find the source...I just recently did some work on my alt, so i know all belts and pulleys are tight and good, but the water on the belt is an interesting theory (we were pretty heavily weighted), but I'm leaning more toward intake leak due to how it was fixed last time. Maybe i'll just check all my impeller housing fasteners, see what that does.
Thanks again guys! I'm taking it out this weekend, so i'll do some troubleshooting on it and let you all know.

I found the source of my noise!!!!!

This morning I was riding withsome friends when all of a sudden my boat starts making that strange squeal we've been talking about. I ask one of my friends if he can hear it and if so, does he know what it is?

He says sure I know what it is........

At the time the noise started we had a downed rider in the water. We were bringing the rope back to the rider. The rider grabs the rope with his hands and holds it allowing the rope to pass through his hands.

The noise is the vibration from the rope passing through the downed riders hands!!!! The vibration travels up the rope to the tower and echoes through the hollow tubing of the tower!!!

Can you F'ing believe that??? Neither did I. To prove it, when my friend was in the water on his next run he grabbed the rope and let it pass through his hands. He asked if we heard the noise, we did. He would then let go of the rope and there was no noise. He grabbed it again, the noise is back. He lets go, no more noise.

Who would have ever thought......

Richard,

You may have just solved a problem for me.
I am new to the wakeboard boat game, but not mechanical stuff.
When pulling a boarder out of the water, I sometimes hear a noise that sounds like the serpentine belt on the engine slipping. After checking the belt, all the brackets, the packing nut, impeller, etc., I now realize it only happens when towing from the extended pylon.
If pulling a skier from the standard pylon, or other toy from the rear of the boat, no noise...
Interesting...thanks..

I second Mikeski and his suggestion, check the shaft log it might be too tight.