Serpantine Belt Noise

[scohow]

I have a mercruiser 5.0 MPI in a 240 sundancer. Every once in a while when first starting the engine I get a squeel from the belt and the engine doesn't fully catch. I try this once or twice, leave it for a few minutes then try again and it starts right up, no noise. I am assuming the belt is slipping and should probably be replaced. The engine stalls due to the slipping belt and engine not being warm? The belt looks fine, no cracks or glazing. Might be due to moisture on the belt as this happens after the boat has been sitting for a few days and is kept in water. I would appreciate any thoughts.

Thanks!

 

[Lazy Daze]

Maybe the wrong size belt is on there? Check the part number on it and verify with your parts manual (you can download it from the SR website) or call a merc dealer.

Are you sure it's the belt and not a pulley bearing?

 

[scohow]

I believe it's the right size belt and haven't had any issues except for the two mentioned. Is there a way to diagnose belt vs pulley bearing? Assume if the bearing is going then it stresses the belt resulting in the slippage? Stupid question, but there are pulley bearings on each component tied the the belt or more specific to the tension pulley?

Thanks!

 

[tdappleman]

Best thing to do is actually remove the belt - remember how it goes on and/or take a pic to make sure you get it back correctly. While it is off - test the idler pulleys as well as the belt tensioner. Both pulleys should spin freely with no noise and not wobble on their bearings. You could also have a worn belt - if the back side is shiny or if there are any cracks at all on the ribbed side then it's time for a replacement. Belts aren't expensive and it's an easy enough fix.

 

[scohow]

Thanks, I was thinking that might be the best next step. So if the pulleys all move freely, etc. it's probably belt? I am thinking it might be good just to change it out and use the existing as a back up.

Appreciate the help!