silverknight
Cadet
- Joined
- Jul 8, 2011
- Messages
- 9
I have a 1989 Baja with the Merc 5.7 sterndrive. I tried searching, and found lots of issues regarding alternators, but none that answered my question.
Background:
I have been experiencing some electrical issues. While out on the water, I noticed that my voltage gauge would jump to around 15-16 while on plane and then jump back to normal. The very next time I go to take the boat out, I get a few spins on the starter and then the battery is too weak to start it. So, I check all the wiring to be sure everything is tight and corrosion free. After this, I also had the battery tested since I knew it was about 5 years old. It turned out that it was bad. So I replaced it. After installation, I took the boat out the following weekend. Everything seemed fine, but I would still get the occasional quick jump to the 15-16 volts on the gauge. This last time I took it out, while on plane, the gauge pegged to the high side and I could hear what sounded like a squeal (only while the gauge was pegged). While headed to the dock for lunch the gauge dropped to 12 volts. When I returned to the boat and started it, the gauge was still showing 12 volts regardless of RPM.
Equipment: The alternator appears to be the original alternator to the boat. The date code shows 08-88. It is a Mando. I had it tested and it appeared to be working correctly when tested. The guy who tested it runs a battery/alternator/repair shop local to me. He indicated that the high voltage reading would likely be caused by the voltage regulator.
Question: Should I replace the whole alternator or just the voltage regulator?
Thank you in advanced.
Background:
I have been experiencing some electrical issues. While out on the water, I noticed that my voltage gauge would jump to around 15-16 while on plane and then jump back to normal. The very next time I go to take the boat out, I get a few spins on the starter and then the battery is too weak to start it. So, I check all the wiring to be sure everything is tight and corrosion free. After this, I also had the battery tested since I knew it was about 5 years old. It turned out that it was bad. So I replaced it. After installation, I took the boat out the following weekend. Everything seemed fine, but I would still get the occasional quick jump to the 15-16 volts on the gauge. This last time I took it out, while on plane, the gauge pegged to the high side and I could hear what sounded like a squeal (only while the gauge was pegged). While headed to the dock for lunch the gauge dropped to 12 volts. When I returned to the boat and started it, the gauge was still showing 12 volts regardless of RPM.
Equipment: The alternator appears to be the original alternator to the boat. The date code shows 08-88. It is a Mando. I had it tested and it appeared to be working correctly when tested. The guy who tested it runs a battery/alternator/repair shop local to me. He indicated that the high voltage reading would likely be caused by the voltage regulator.
Question: Should I replace the whole alternator or just the voltage regulator?
Thank you in advanced.