2006 SV211 w/ 330 Excalibur - Buzzing noise from the rear of the boat?

[TeamPear]

Hey Nautiquers,

I have a new buzzing noise coming from the rear of my motor. This does not seem like belt squeal and might be a pulley bearing? Any ideas about what this might be and/or diagnosing it? Much appreciated!

https://youtube.com/shorts/9V33htW5Y...wKLh7BHkY0_JC5

[NautiqueJeff]

That's actually the front of your engine. Remember, engines are mounted backwards in v-drive boats.

That is a weird sound for sure. I'd start by removing the belt and briefly starting the engine to see if the noise goes away. Assuming it does, it is probably either your alternator, water pump, or possibly one of the pulleys or the tensioner. There isn't anything down in your bilge that is contacting the belt, is there?

[SilentSeven]

Odd one. Curious to learn what this is. +1 for Jeff's suggestion.

[bturner]

I'll take idler pulley for $50 Alex.

Jeff (as always) is spot on. It would be interesting to hear if the frequency changes with the speed of the engine. That would almost certainly tell you it's something rotating with the engine and associated with the pulley system. If you want to try something without pulling the belt you could get a spray bottle with water and try spraying the bearing surfaces lightly with water one at a time and see if the sound changes. That should work for the alternator, idler and raw water pump but won't do much for the engine water pump.

The last thousand mile away trouble shooting suggestion would be to make absolutely sure nothing has rolled around the bilge or fallen into the engine that could be rubbing on the rotating assembly. And yes I "fixed" one where a can of WD40 somehow made it into the bilge and was causing a strange noise.

[TeamPear]

I started the boat out of water and am not getting the sound (it's consistent when in the water). I pulled the belt off. The pulleys generally feel pretty good, but the tensioner does have a very slight play to it. The water impeller has a one directional rub - I'm unsure if this is as intended since I'm new to boat maintenance. It rotates with some friction (like slight rub on an oring in one direction and much more difficult to turn in the other direction - this is a yearly replacement item and something I'll take care of. This boat is a 5.7 and does not have the idler of the larger motor. Planning to get a new tensioner, belt, and water impeller and try a water launch again.

[mpost]

I would take the impeller out of the raw water pump and see what the bearing sounds and feels like when spinning without resistence. How does the water pump and alternator sound when spinning by hand? definetly sounds like a dry rusty bearing to me.

[TeamPear]

I got back there and did some wiggling:

The impeller seems to be a bit loose and makes a loud pinging noise when rotating back and forth on the pulley (video 1). The pump bearing behind it felt really solid, no play, no slop, no noise. Obviously, I replace the impeller, but do I also need to replace the bearing housing?

The tensioner pully can wiggle a bit and makes some noise. Not sure if this is a normal amount of play (video 2). Is this something to replace as well?

I definitely need a new impeller, but do I also need the impeller housing AND tensioner? Opinions welcome!

https://youtube.com/shorts/qDrZvaksuVE?feature=share

https://youtube.com/shorts/IgL9lmg2P-M?feature=share

[mpost]

I dont believe the tensioner pulley should be that loose. What does it feel and sound like when you spin it with the belt off. any noise or rough feeling is bad. Should be smoot and silent. Also what does the Pump bearing sound like and feel like when you hold the pump body and spin the pulley? Same here. it should be smoot and quiet.
I replaced the pump on my 84 2001, back in 1998. They were pretty cheap back in those days. I did a complet rebuild on my 98 pump when I bought it 6 years ago with 1100 hours on it. It was rough and loud and leaking. Parts are availble but it is a project. definately would not try without a press.
Here is the a link to a post I did on my rebuild. https://www.correctcraftfan.com/foru...wood-pump-help

[pauldixon]

if you have one, can borrow or buy a mechanics stethoscope you should be able to pin point the issue pretty quick