My engine was throwing warning alarms at the end of a trip. I installed Vessel View, and it indicated a bad oil tank sensor, so I ordered a new tank, replaced it, and all was good for a while, then the alarms went off again. So I parked the boat for the season.

Over the fall/winter I replaced switches, the old gauges, and I replaced the batteries with huge HD ones, as the old ones kept needing to be charged, even though they weren't old and were 1000A batteries.

Today, I decided to run the boat. The brand new batteries read 13.1v. She started instantly and sounded good. I ran her for 10 -15 mins on the hose with no alarms. But then I noticed less than 12v on the gauge. The multimeter showed 12.6v at the solenoid and at the batteries, but when I started her, it dropped to 11.77v. She is not charging at all.

Now I'm wondering if all my issues aren't actually due to low voltage. I know that newer engines need good voltage. Unfortunately, my "2002" manual from Ebay is actually for a 1998/1999 Optimax, and it's a different charging system. There is no "Terminal B" to ground that I can see.

So, I need help. Does anyone know the procedure for testing the regulator and rectifier? I've got battery voltage but no output. Thanks.