Idler Pulley - 2008 Merc 350 Mag

[km2006]

Hi there.
I've read thru similar subjects, but have not been able to relate.... Hoping you guys might have experiences that can help me.

Noticed yesterday that the belt was lightly squeaking. Opened up the door and saw the belt is only running on about half of the idler pulley nearest the pump. Running in the middle on the other pulleys. I have never seen this before.

 

[Bt Doctur]

bearing going bad?

 

[km2006]

Thank you. I will know for certain once loosening or removing the belt. Is your theory based on if the bearing were going bad, the pulley would not be supported and then could not support the forces from the belt?

 

[Bt Doctur]

the pully rides on a bearing that is bolted to the mounting plate If was aligned at some point and now its not so either the bracketry is bent outward or the bearing is going bad,tilting so to speak.

 

[km2006]

Will look at that very thing, thank you. I'd assume it to be loose if the bearing is bad. Or I will just have to feel for it sticking/not smooth.

 

[Bondo]

I'd assume it to be loose if the bearing is bad. Or I will just have to feel for it sticking/not smooth.

Ayuh,... It'll be "Noticeably" Bad to the touch,.....

A Blind man could make the diagnosis,......

 

[km2006]

Does anyone have a picture or two of the pulley, and the two brackets it connects too? The pulley is like 3/4” off center towards the engine (as seen in the original pictures). I flipped the sequence in which the brackets overlay, but that didn’t help. It’s almost like I’m missing a big spacer. The pictures in the manuals and online show that I have it all correct......

before leaving the boat today, I took the large bracket off the alternator and put it on the outside face of the pulley bracket. This aligned the pulley. But the bracket is now about 3/4” away from the alternator.

Also, my boat has the bolt on the outside face of the pulley, which doesn’t seem right. I would think the flanged nut would press against the bushing....?

thanks everyone.

 

[Bt Doctur]

 

[Bt Doctur]

the raw water pump is installed first then the idler bracket goes on next, then the lower nut on the stud and the bolt on top

 

[km2006]

The water pump bracket is like an “s” bracket with a bolt and a nut over a stud? The idler bracket is the long thin plate bolted to the alternator? And this is over top of the pump bracket. The stud is above the bolt on the pump bracket. This is the order I have them installed. All fasteners are secured accept the one to the alternator as the bracket is so far away. I should of gotten a picture. Dang it.

 

[km2006]

[No message]

 

[Bt Doctur]

 

[scoflaw]

your raw water pump is failing and the shaft ,seal, bearing assembly, along with the pulley is headed outbound, bringing the belt along for the ride

 

[Bt Doctur]

 

[Bt Doctur]

scoflaw, if that were the case it would be leaking water , a lot

 

[km2006]

So you feel the water pump is bad/going bad and the water pump pulley in the diagram you posted is pushing out? This is why in the original picture I posted is showing the belt coming off the front side of the pulley?

ive never heard of a bad pump doing this...... I did replace the impeller last winter and added all new seals.

 

[scoflaw]

Maybe he hasn't noticed the water. Tryin to drum up a little biz for yah. Looks like some kind of somethin under the pump

 

[km2006]

scoflaw, if that were the case it would be leaking water , a lot

no water leaks.

 

[Bt Doctur]

I just rebuilt a leaker like that

 

[Bt Doctur]

any chance the wrong alt was installed and made to fit?