Serpentine belt problems

[norcalatver]

A month and a half ago I had my local boat shop replace my impellar on my 1997 Tige' 22V. The very first time I took my boat out after the serpentine belt whined the entire time I was out. ( I have never had a problem before). The shop thought I should replace possible bad belt so I had them do it.
First time out with new belt it whined real loud again! I called shop and they thought it might be bearings in one of the rollers? So, the second time I took it out I brought some belt dressing with me and some WD-40. Turns out the belt whine went away with belt dressing.
I thought my problem was partially solved when all of a sudden, after 2 hours of boating, my belt came off and was all frayed. This belt has about 4 hours on only.
What could the shop have done wrong? I have only replaced the belt once in 500 hours, now all of a sudden after the impellar is changed, I have major problems with it. Could they have possibly not reinstalled the pulleys properly?
Any advice is appreciated!

[zad0030]

Maybe its not tight enough. Or the impeller housing is beat up and not allowing the impeller to spin freely, or maybe the wrong size

[samw]

Maybe its not tight enough. Or the impeller housing is beat up and not allowing the impeller to spin freely, or maybe the wrong size

Agree with zad, check the alignment of the water pump the the other pulleys make sure they align. That could cause the the bellt to be fraid and noisy...
Just a thought.

[norcalatver]

Agree with zad, check the alignment of the water pump the the other pulleys make sure they align. That could cause the the bellt to be fraid and noisy...
Just a thought.

Does the water pump have to be removed to replace the impeller? If not, it doesn't make sense it would all of a sudden be out of alignment. Thanks for your quick responses!

[zad0030]

Does the water pump have to be removed to replace the impeller? If not, it doesn't make sense it would all of a sudden be out of alignment. Thanks for your quick responses!

Depends on the engine. Mercruiser needs the whole pump removed.

[samw]

Does the water pump have to be removed to replace the impeller? If not, it doesn't make sense it would all of a sudden be out of alignment. Thanks for your quick responses!

Norcalatver,
you do have to remove the water pump to replace the impeller....

[TRD]

Nor,

I had to change my belt this year after my impeller got ate up. Once I put the new belt on all the noises went away. I used a straight edge to check to see if my belt was aligned. It is easy to do. I think you may have the same engine I do so if you need numbers let me know.

[R&T Babich]

Check the 3 bolts that hold the raw water pump to the mounting bracket. I changed our impeller and the 3 bolts worked loose after a couple of hours - not so much whining, lots of black rubber powder, then threw the belt. The bolts were long enough to double-nut them and I noticed there was a place to add a 4th bolt. A spare pump I have had bolts that were not long enough to double-nut so I did the same to the spare - longer bolts, 4th bolt and 2 nuts. No problems since.

[dogbert]

zad is right about the tightness. Also, Mercruiser lists the wrong part number as a replacement. Your best bet is to take your old belt to a local auto supply place like O'Reilly's and they can match it up. My buddy had the same thing happen to his 21v and that's what fixed it.

[Fast1911]

The belt could be the wrong size like dogbert said. I had no part number on my belt when I replaced it. The auto parts store will have a tool to measure the belt length. Also, look inside the pump housing next time to make sure it is smooth. The housing will wear out eventually and might have to be replaced or you will chew up more impellers. It happened to me.

[TeamAllen]

There were a few earlier threads on this. There was a Merc. service bulletin on aligning the belt and there was another thread that mentioned someone getting an automotive belt and having either more or less grooves in the belt. I'll see what I can find.

[norcalatver]

There were a few earlier threads on this. There was a Merc. service bulletin on aligning the belt and there was another thread that mentioned someone getting an automotive belt and having either more or less grooves in the belt. I'll see what I can find.

Thanks,
I found the thread with the service bulletin and printed it off. I'll be calling the shop where its at this A.M.

[TeamAllen]

Glad you found it. I hope you get it fixed.

Here are the links in case anyone else need them.

http://www.tigeowners.com/forum/showthread.php?t=4706&
http://www.tigeowners.com/forum/showthread.php?t=1641&

[venetrex]

belt eating

My 21v 2002 used to eat belts alot. I had 3 problems. 1 was belt alignment, I had to shim out one of the pulleys with washers. 2 was the dam solid brass seawater pump. The back plate was WAY to tight against the impeller . I actually grd it down and then sanded it smoooth so there is an indentation there. 3 this problem took me years to figure out. Ever try to start your bought and have it not start and when yolu turn off the key have the engine diesel, fire and run backward one rev or two. This would cause the impeller to get stuck so the belt won't turn it. And if you run it for long the belt will break. I would loosen the tension pulley, 5/16 socket and a 5/8 wrench to do this(always have these on board). Loosen the belt and turn the water pump by hand in the correct direction. The main cause of this turns out that the mercruiser mag MPI wont fire if the battery is even slightly weak. Well these were my problems anyway.

[R&T Babich]

...The main cause of this turns out that the mercruiser mag MPI wont fire if the battery is even slightly weak...

I'll bet most engines these days will not fire with a weak battery. The battery is usually sitting around 12.6v and when cranking the starter will drop to around 9.5v. If the battery charge is low the cranking voltage may get down to 9v. The engine ECM won't run below 9v or so.