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Mercruiser 4.3LH Serpentine Belt

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Proud owner of a 1999 1830SS with the Mercruiser 4.3 LH. Had the Chap out on the Tennessee River @ Pickwick over the July 4th weekend. Late on the 4th I discovered that the serpentine belt was shredding on the front edge. It appears to have walked forward. No engine run problems. I did observe that the alternator was not charging at the normal rate, but still 10-11 volts. I discovered the problem while stowing the canvas top.

Anyone have knowledge why the belt would walk forward on the pulleys?

Thanks

Chuck

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The belt could have stretched over time or the idler pulley bearing and/or bushing could be shot, causing the bearing to wobble (happened to mine). Whatever, get a new belt. Recent recommendations have been to change the idler pulley and bushing at the same time. It's about another 40 deer, but will prevent losing the belt prematurily. Hy

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Personally, I'd go with a Goodyear Gatorback serpentine belt; A LOT quieter during operation. What is the MerCruiser 57-......... part # currently printed on your belt? One other thing to look as is whether or not the power steering pump pulley is plastic or metal. If the pulley is plastic, you'll want to get it replaced first, then have the correct longer length Goodyear belt ordered to go with it.

If the power steering pump pulley is metal, all we need to do is match up a new belt. There was an issue with the plastic pulley breaking, thereby ruining a good day of boating.

Lastly, what is your engine serial #? Should have a sticker on top of the carb flame arrestor cover starting with engine serial number 0L......., or if not there, a plate can be found riveted to the block directly above the starter motor with the engine serial number.

Always liked the 4.3 LH and LXH; last of the stock 4 bbl. 4.3L V6 engines from Merc.

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I found the problem! Thank you for all of the suggestions.

What I found.... The alternator brace from the lower block to the bottom lug on the alternator was broken. It broke right at the alternator. Looks to have been a bad stamping from production based on the internal staining. This allowed the alternator to pivot or flex when loaded up. Installed new brace and belt, and all worked as advertised. This brace is used on the V6 and the V8 engines.

Chuck

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Good note to self, and all others, if a serpentine belt system wears a belt on its edge, The problem is allways an alighnment problem. Wheather u r in a boat or a 18 wheeler. the engine componants are all in a lignment. unless the tensioner is bad. I hope all who read this will ck there belts. Nothing ruins a good day on the water, than a bad belt .

Have a great day

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I just had my belt come off. The belt looks fine but now I'm concerned why the belt came off. I did over- rev at start up. I put the belt back on and no problems...

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