shredded serp belts

[clinton]

Hi all, thanks for taking a look at my post.

I have a 99 21V riders edition w/ the 350 MAG MPI.

The problem I am having is that I keep shredding the serb belt. I bought the boat last fall and after 2 or 3 outings it seems as if that is when the belt will shred. I appears that everything is in line when I put a new belt on as far as the pullies go.

How can I isolate what my problem is?

Thanks.

[ghollow]

I had a problem similiar to this when I first bought my boat. My problem was that the pulley on the harmonic balancer had rusted and was slowly cuasing the belt to disenigrate(?). You might also check and make sure all of the other pulleys turn freely.
Have you changed the impeller in the raw water pump? If the impeller has started to come apart, it may be causing extra drag on that pulley.

[clinton]

is the raw water pump the unit on the lower port side on the v drive? so, no I haven't changed the impeller. That pully turns the hardest but all others turn freely, except the crank of course. Also I did notice some rust on the harmonic balancer. I will take care of those things. How do I change the impeller?

[clinton]

The alternator pully is rusty, i steel brushed it and it seemed to help. Can I get a new pully? or do I need to replace the whole unit?

[Tige M.D.]

you can just replace the pulley.

is there alot of rubber dust all over the alternator? if so, take a straight edge and check the face of that pulley to the rest. you might need to shim the alternator bracket.

[clinton]

Tige M.D.

there is belt dust all over inside the engine box. Not as bad after steel brushing it. Thanks for your reply. Can I replace the pully myself? or do I need some type of puller?

[Tige M.D.]

just an impact wrench and a socket. very quick and painless.

[clinton]

thanks

[bmyers98]

I have having the same problem. I've gone through 3 belts in the last couple of months. I keep reading and hearing about needing to shim the alternator. I believe this could be my problem. Anyone have any information on said alternator shim? In my case it appears the alternator pulley may be closer to the engine block because the front edge of the belt (closest to the driver) is rolling up and then it starts to separate not too long after that.
Thanks!

[TeamAllen]

I would think washers from the hardware store would work, but I found these.
http://www.ebay.com/itm/Alternator-P...-/230751885094

[mdk681]

Take a look at the service post here:

http://www.mercruiserparts.com/bulle...2003/EN_04.PDF

[TeamAllen]

Well there you go with the correct part #. Good find.
http://www.boatstore.com/mercury-qui...95-spacer.html