Belt Pullies
 

While reading the engine and maintenance section . I noticed a couple of comments pertaining to fan and alternator belts . I am the third owner of 1996 Shabah 250, the original owner used the boat in salt water in the Gulf of Mexico. The next owner used the boat in freshwater only, as I also plan on doing.I bought the boat this past September and took it out three times before putting it up for the winter. First time out the boat ran great, second trip the belts started to squeal when first accelerating. I tightened the belts before my third trip out,on my third trip out the belts were quiet at first but then got noisy once again. I anchored for a couple of hours as it was a beautiful October day. When I was ready to head in I had a hard time starting the engine because my batteries were weak. Previous owner had told me that he had recently put in a new alternator belt and a couple of new batteries so I was curious as to why the batteries were weak. I opened the engine compartment and immediately noticed the alternator belt was chewed up but still in one piece.Upon further inspection it was determined that the belt pullies were corroded and pitted and rusty looking which would slowly ruin my belts. The pullies will have to be replaced before any new belts wiil be put on. I guess it is always a good idea to closely inspect the condition of the pullies before installin a new belt. I now know first hand the corrosive power of salt water.

yuch. tough lesson to learn but at least she didn't break down on you well away from land....

i wonder how many times the prior owner replaced the belts rather than find the cause & replace the pullies.

Wrong Belt?
 

Another thing to check... Aside from any corrosive build-up on the pulley, your prior owner may have simply put on the incorrect belt. Each pulley (e.g. alternator, power steering, etc.) has a specific radius, width, and pitch. If he put one in that is not the correct one it will force it to seat too low in the pulley and that puts the stress on the fat band on the outside and chews up the belt.

As you take the belt off and wire brush the pulley to ensure that it is smooth, if there is corrosive rust, after you brush it down, at hardware/homestores you can get a Loctite Extend Rust Neutralizer in a spray can. That bonds to the rust and molecularly stops it. This is some great stuff.

Unless you have true bass boat or a high end boat dedicated to skiing, here in FL the majority of the boats see salt water. I have slowly had to re-surface the front of my engine. Actually there was corrosive pitting on the front of my power steering pulley. I went at it with a drill mounted wire brush and cleaned it up - or so I thought. Giving new meaning to the joke - the rust is the only thing holding it together - on one of my next trips out the pulley actually broke! The metal was so thin that the rust had eaten through it. I had to rough-ride it home with no power steering. I have since put a new pump in and while that side of the block was exposed I cleaned everything up and re-enameled the engine. Just something to stay on top of.

By the way.. Keep on top of that bolt/nut thing on the front of the power steering pulley with grease or something, that is a "special tool" removal system and if it gets too corroded to remove it, then you end up replacing the whole pump.

Wow, I'm glad I boat in fresh water...

I have enough problems with my land vehicles rusting from all the salt that gets used here in the winter... :shakehead:

Sierra Merc Belt Guide.
 

ronbeco13,

Just in case it is the belt, I dug around and located the following from Sierra for Mercruiser V-Belts. I could not find the original web link, however I had saved it and printed it out so I could keep it in my repair manul. You can use a Mercruiser guide to get the Merc Part number for you engine serial number and then cross that to a Sierra. The guide then has the width and other information for that belt. That way you can take a caliper or something and measure what is currently on the pulley.

Hope this helps.

Thanks,

Bill DeWeese