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Jim Jim is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 338
Default Battery Won't Charge While Engine Runs


wrote in message
ups.com...
I have an 84 Wellcraft 200 elite w/a 260HP merc. Symptoms are as
follows:
- Battery never charges while under way after a day on water. Has died
sometimes but I take a spare. Still, no fun.
- Dash voltmeter never reads more than 11V --usually less. I recharge
bttys before each trip. 11V or less even w/new battery.
- Have to retighten alternator belt often. Rubber dust on engine hood
says it's getting ground down. Running out of room on adjustable bar
for Alt.

Here's what I've done so far:
- Brand new marine battery, new Alt and Starter last year.
- Brush corrosion from posts, cables, wires.

While idling, Alt reads 40A on back w/ multimeter. No juice getting to
btty, tho. Someone said maybe Alt pulley is wrong size (tho I gave old
one to match at Alt shop). Said maybe a '9 series' pulley to match belt
#9440. Alt shop guy never heard of it tho. How crucial is belt brand?
Have matched size of new one from auto parts store to old one.

Any ideas much appreciated! THANKS. -- STB

Try a brand new marine belt of the correct dimensions. You probably won't
find one in an auto parts store.
Check belt alignment.
Check for rust on pulley belt surfaces.
Check to see if the fuse between battery and alternator is good.
Keep belt tight at all times. Make it part of your pre-op checks.