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Alternator belt slipping

PostPosted: Tue Apr 27, 2010 8:19 am
by Skip
I have a one year old Yanmar engine with 55 hours on the engine. When the boat was comissioned last year there were 600 amp hours of AGM batteries installed and an Ample Power 4023-S alternator with a 2.6 inch pulley. The original Mitsubishi belt is still being used.
I recently had a mechanic on board and he said there is more than the normal amount of belt dust coming off the belt in the alternator pulley area. He said the belt tension is correct. He was able to turn the alternator fan blades by hand and the alternator pulley turned under the belt. He said a larger alternator pulley would add frictional are to the belt and prevent slipping but was not sure there would then be enough clearance between the belt and the raw water pump.
My questions to you are as follows:

1) I read in the forum that you recommend Dayco Top Cog belts. No auto parts stores carry that brand in my area nor have they heard of the brand. Where would you recommend finding these belts.
2) Would you suggest a 3 inch pulley if I have the belt clearance for it. Most of my charging is presently done by shore power thru the battery charger but eventually when I take longer trips sometimes charging would be done while cruising under power.
3) If you suggest changing the belt and pulley should I first try the belt change and see how that works or change both the belt and pulley at the same time.

Thank you for your advise.

Re: Alternator belt slipping

PostPosted: Tue Apr 27, 2010 12:52 pm
by Coulomb
The sheave will work with a Dayco Top Cog belt and proper tension.

You can start here to find a dealer in your area.