Alternator not charging Battery?

[USMCMatt]

I suspect that my 94 85hp force is not charging by battery correctly, after a few trips, I have a small battery tester (unmetered) that simply shows bat level and atl charging output with a stupid light that says low.

Does anyone have a good faq for the electrically challenged? I own a multimeter but not sure what/where I'm looking for to figure out if something needs to be replaced.

 

[Barnacle_Bill]

Re: Alternator not charging Battery?

You can verify that it is not charging by monitoring the voltage at the battery. Check the voltage with the motor off then check it again with it running. As RPMs increases so should the voltage. If it doesn't check your rectifier/regulator according to your manual.

 

[USMCMatt]

Re: Alternator not charging Battery?

Great thanks!

 

[john from md]

Re: Alternator not charging Battery?

Thanks for your service Marine.

Now, do yourself a service and buy a cheap multimeter from Harbor Freight or Sears. Set it on DC and read the rectifier red and black poles. This should be about 13 to 13.5 at 2000 rpm. At WOT it should be 14 to 16 volts.

These go bad all the time. Search for rectifier and you will get plenty of info and part numbers. You can get a replacement from Radio Shack.