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Alternator stripping the belt and running very hot

PostPosted: Tue Sep 18, 2012 3:25 pm
by BillMc
I have a 12V alternator, model no 4023/s #RR2023 together with a V3
regulator.
I guess it has been in the boat on a Yanmar 4JH3E 50HP engine with
400AH AGM house batteries for about 600 hours/ 6 years.
On a trip to Vanuatu this year it failed. The fan belt stripped.
It was disassembled with no apparent fault and reassembled. It
rotated freely by hand and when replaced produced normal output, but
then stripped the belt quickly and was very hot.
I had to replace it with a standard alternator for the remainder of
the trip. I don't think the pulley was slipping.
Questions.
Would bearing failure do this?
Should I get a rebuild kit?
It has always produced a lot of rubber dust from the belt, I was
using a Bosch 13mm A profile inside cogged belt.

Re: Alternator stripping the belt and running very hot

PostPosted: Tue Sep 18, 2012 3:34 pm
by Coulomb
Sounds like belt slip. When was the belt replaced?

Use a Dayco Top Cog belt for best performance. Make sure the tension is adequate.

The alternator will always be too hot to touch if it's producing full output.

Re: Alternator stripping the belt and running very hot

PostPosted: Wed Sep 19, 2012 4:07 pm
by BillMc
The first Bosch belt lasted 3 years so I cannot understand why the second one lasted 2 hours.
Would a bearing failing under load do this?
Bill.

Re: Alternator stripping the belt and running very hot

PostPosted: Thu Sep 20, 2012 10:11 am
by Coulomb
Bearings are possible. Have you checked for play? Does it spin freely?

We don't know anything about Bosch belts, but typical automotive belts don't last long. Was this the first time you charged deeply discharged batteries?