Mercruiser 5.7 - Bad alternator bearing?

[keysersoce]

Hello,

When I first start up the engine it runs fine, and then a minute or two later it starts to squeal really bad. This seems to coincide with a slight bump in the voltage reader gauge.

See video here (19sec). https://youtu.be/9U9xkC2XhYE

Thanks for any advice you can offer.

 

[Bt Doctur]

fan belt is no good or riding too deep in the pulley or its loose

 

[keysersoce]

Thanks Bt. I'll just try a new belt. Any reason it would take a few minutes before squealing?

 

[Bt Doctur]

the alt is not in charging mode at 11 volts, once the rpm`s increase its trying to charge the batteries but it cant because the belt is slipping on the pulley.

 

[Silvertip]

Just push on the belt midway between the pulleys. It should feel tight. If you can easily push the belt down 3/8 inch or so adjust the tension. If the belt is worn or cracked, replace it and adjust it.

 

[keysersoce]

Thanks. Yes, I can push it 3/8" pretty easily.

That makes sense regarding the rpms. It starts off at about 500 (no noise) and slowly builds its way up to around 600 after it warms up (noise starts). Noise also gets a lot worse/louder when revving it up in neutral.

I'll try a new belt; I really hope it's that simple. Thanks again for the help.