What is this sound?

[Kikaboo]

Here is the history. 2015 32 Express Merc engines.

1) Merc engines are 3 years old ( going into 4th season) so had marina do the required water pump impeller change over the winter layup. Upon launching the boat, I noticed a squeak sound on starting the SB engine. Before I took the boat I brought this to the attention of the services guys who said they heard it as well but it should "break" in and stop after a while. Told me to use the boat and if it does not go away in 2-3 weeks bring it back. The squeak would only last a second or two.

2) Boat was launched, drove 15 minutes no wake zone but as soon as I throttled up, SB engine overheated. No water going to pump, etc. Shutdown SB engine and returned to port.

3) Serpentine belt was completely lose. Marina checked out the boat and said tensioner went bad and replaced that and a new belt. Said still not getting enough water so pulled the drives and cleaned everything out. Boat seemed to be working okay now, although water PSI on SB motor at 4000 rpms is like 14-15 while the port motor is 17-18. Both engines are running normal temps at around 159-163.

4) The issue now is when cold the SB motor squeaks. My wife says it sounds like crickets. This seems to happen when the motor is cold but sometimes the sounds goes away but other times stays persistent, even at 4000 rpms.

Click the youtube link below to hear the noise.

https://youtu.be/j3felqz6avI

There were zero issues with the motors when I took the boat in for the winter layup and before water impeller change.

Thoughts?

[Bt Doctur]

you have a bad belt or improperly tensioned , the idler pully can also squeak

[cbsmith]

That’s a fan belt or pulley squeaking. If you’ve replaced the tensioner pulley already it could be the idler. Or it could be belt alignment. There is lots of advice on google on how to check for them with a spray bottle of water and/or a mechanics stethoscope.

[gofast24]

you have a bad belt or improperly tensioned , the idler pully can also squeak

Agree, Could also be the alternator brushes/bearings (sounds like brushes to me) . Another thing to check would be the spring loaded belt tensioner, squirt (spray) a little "Super Lube" lubricant into the inside of the spring housing and on the shaft that comes thru the housing, dont get any lube on the belt or pulley!

[Kikaboo]

All...thanks!

The service tech also thinks it could be the idler pulley is losing a bearing....says it will get more continuous as time goes on, eventually will lock up and throw the belt.
They sent a mechanic to my boat this am to check it out and will let me know. Good thing is it should be a warranty item.

Just reinforces the notion if something doesn't sound right, look right or smell right...have it checked!

[gofast24]

Doesnt sound like a bearing, bearing usually have a rattle, squeaks are usually something slipping or sticking. If you can remove the belt turn the idler and tensioner pulley over by hand and it should feel nice and smooth, if it wobbles or feels "sticky" it is the bearing. Good luck, let us know what it ends up being.

[Kikaboo]

Tech checked and says its one of the idler pulleys and will be replaced under warranty. Thing is its on back order until June 15th.... so I am not sure how "safe" it is to use the boat between now and then. I suppose I will just stay local and only go out in good conditions in case it goes south and I lose use of that engine while underway.

[gofast24]

If the tech was really good he could just press out the old bearing and press in a new one (usually a standard xxxx -2RS (two radial seals/permanently lubricated bearing) , but that means a shop with a mechanical or hydraulic press in available. Probably OK to just run and stay close to home. As you have twin engines you could easily make it back to dock on one if the one with the bad idler failed (seized). Backing into a slip on one engine is another job, done that twice .

[Bt Doctur]

dayco 89017
https://image.ibb.co/doLkSo/DSCN3589_zpsu2f7alxj.jpg

[gofast24]

If this is his idler pulley most likely cant save any money pressing out the old bearing and pressing a new one in? Anyway, OP indicated it was under warranty.