Screeching noise during accel

[Leedhn]

I operate a 290 5.0 BIII . We were out Saturday for a trip, all systems started fine and we idled out of our marinia. All readings were normal. I had hit the trim buttom for the SB drive by mistake and put her back down. After clearing the no-wake zone I powered up to speed; about 10 seconds into the process I heard a loud screeching noise but no rev drop in any engine. My first thought was some type of drive train slip. I wentt back to the dock, went below to check everything out and it all looked,smelled and sounded normal. In gear, with lines cleated shifting was normal in both forward and reverse. I made my trip and the rest of the day was normal. Could engine thrust have overcome the tilt setting if I had not put the drive in the full down position during high loads coming up to speed and forced lube back thru a valve causing the noise ? Do you owners of 5.0 BIII have any insight for me before I have my dealer check things out.

 

[Robski97]

Could it be something as simple as a slipping belt?

Rob

 

[fc3]

Sometimes I hear a loud screeching sound when running at speeds. It's a bit perplexing, but then my wife grabs my arm and yells, "Slow down!" Did it sound like that or something else? If it was bearing or something expensive, that noise doesn't just go away by itself.

Best regards,
Frank C

 

[osd9]

The turbos spooling up......:grin:

 

[Leedhn]

I wish:grin:

Lee

 

[Kendall]

Most likely the engine accessory drive belt.

If it was mechanical it would not go away and you would see rpm's drop.

 

[boatrboy]

Could it be something as simple as a slipping belt?
Rob

That is my first thought. Just tighten the belt slightly and see if there is any difference. Mine would make this sound when cold only until I adjusted the belt tension.

 

[Leedhn]

I guess it could have been a belt, it just sounded more mechanical at the time; and I agree if it was a serious mechanical issue it would have just not just gone away. It has never happened before and it gave me an Oh s**t. $2000.00 is gone.

 

[fwebster]

Lee,

As I recall, your boat sat idle for an extended period of time just before you bought it last year. The odds are the accessory drive belt has gotten hard and probably tired. I think yours is a serpentine belt with a spring loaded idler, so just adjusting it isn't going to help. Just get a spare belt and bring along some tools and change the it before you go out next time.

 

[keokie]

I have definitely had this problem as well. Mine has been a bit like Frank's. Maybe a bit louder though, and definitely more persistent. The only cure is to get the mother-in-law off the boat.

 

[tdappleman]

I have definitely had this problem as well. Mine has been a bit like Frank's. Maybe a bit louder though, and definitely more persistent. The only cure is to get the mother-in-law off the boat.

:smt043:smt043

I second the belt replacement. Check it for cracks on the ribbed side and a 'shiny' surface on the flat side. Both sides of the belt are typically used with a serpentine setup so both sides get worn.

 

[Skeetobite]

I had this with my accessory belts when I replaced both alternators. A short squeal at start up and a loud squeal at high rpm. Went to the auto store and bought a can of spray on "belt dressing". Problem solved.