Belt Noise

[Big Fire]

I have an '02 2100v limited with a belt squeal. This issue has been on-going for almost 3 years!! I've had it in the shop several times and we are struggling to track it down. All of the pulleys have been swapped except the altenator. The belt's been swapped as well.

The squeal only comes up when the boat is under a load or at start up. I'd love some help - I almost considered selling my boat this has been such a hassle.

Thanks!

Big Fire

[tigeidaho]

Is it the mercruiser? Mine was squealing a little this weekend, when i called my buddy the dealer, he said mercruisers are somewhat famous for this. Apparently its the tensioner. Mine is very slight so i haven't pursued fixing it yet.

[sandm]

same issue with our honda car. only when the ac unit was under load would the ac belt squeal. replaced tensioner with an aftermarket unit and all the noise went away..

[R&T Babich]

Is it the mercruiser? ... Apparently its the tensioner...

We have the 2000 350 MAG MPI Mercruiser and it doesn't have a tensioner. There are 2 idler pulleys, but no spring tensioner. One of the pulleys has a geared tightening mount, but the pulleys are the same.

Check the alignment of all the pulleys to be sure one is not quite lined up and pushing the belt to the side a bit. There was a Service Bulletin (No. 2003-04 Serpentine Belt Shredding) that I think only affected models before ours. The problem was a missing spacer on the alternator mount and the pulley was not parallel with the crank pulley. The alt pulley did not have to be in perfect alignment with the crank pulley, but it has to be parallel. Lay a metal ruler across the crank pulley and see if the alt pulley is parallel to the ruler.
I have tried using a Driverite 6PK2225 belt, but it was not a good fit and generated lots of black rubber powder.
We've had a Prestone - 880K6 belt for over 200 hrs with no problems.

[Bakes5]

Mine has squealed for the past 4 summers/500 hours. There is a little crack in the alternator bracket that could possibly be causing it but frankly, I have spent way to much time/effort trying to figure this out. I will likely change out the bracket this winter but doubt anything will change.

[Big Fire]

Just got off the phone with my mechanic. It turns out the bracket for the sea water pick up pump has a crack in it and is out of alignment. New part is on the way - I will update on whether or not this is the solution to my problem.

[jacques2727]

Had the same issue for a few years. Finally followed the service bulletin and installed the alternator spacer. Pulley squeal gone, belt shredding began. Went through two belts one cord at a time. Pulled the spacer out, squeal returned but ran great without shredding through belts. I have now accepted that the alternator pulley is going to squeal and I will learn to live with the annoyance. Dealer is going to try to help me when I pull the boat in for the fall, but I am not overly optimistic.

[Moki]

I have the 2000 23V with the Mercruiser and our houseboat has the same engines as well. They both squeal at start up, but then the squealing goes away with more RPMs. I noticed on my 23V that it is worse when people are getting in from the back and water drips down on the belt.

[Big Fire]

I finally was able to take the boat out yesterday with very positive results. The boat ran very well and more importantly no belt noise.

Talking it over with the mechanic he said that the alignment was off due to a very small crack in the sea water pump bracket. Hopefully this helps somebody out in the future.