mercruiser 350 mag need belt help

[4nryde]

Looking for some belts for tomorrow, but think I might be out of luck. The boat is a 1993 Malibu echelon with the mercruiser 350 magnum tournament ski engine. The alternator belt is making a horrible squealing noise. The alternator belt part number is mercruiser 57-48120, and lake water pump belt is 57-13457. Anyone know if there is a cross reference for these belts. I would love to get one from Napa or autozone so I can possibly float this thing tomorrow.

 

[NHGuy]

Re: mercruiser 350 mag need belt help

Napa has quite a lot of Mercruiser stuff. But before you fork over the $ do the belts look glazed or cracked? If not why not check the tension 1st. And If it's squeaking with a good looking belt and normal tension, take the belt off and give the pulleys a spin. You might find a different problem that way.
Any pulley driven device on there should spin smoothly and silently. Any noise or coarseness is an indicator of failure. Also check that you battery is OK. A weak battery will cause the alternator to work harder.

 

[4nryde]

Re: mercruiser 350 mag need belt help

The lake water pump belt seems good, but that one isn't making any noise. I pulled both belts and compared the top width. The squealing belt is about an 1/8 inch narrower then the good belt. I am going to replace both to be safe.