2000 31 PC
- Thread starter mike 60
- Start date
Electrolysis is not something that is an issue with a model or year but a condition that is caused by dock power, electrical issues on the boat, nearby at another marina, etc. Mercruiser Bravo drives are very susceptible to electrolysis due to the poor aluminum choice from the manufacturer. Any model or year can have this issue.
AllDodge
Well-known member
Need to test a find out what the voltage level is at the drives. This is measured using a digital voltmeter and a Merc test probe. There are other manufactures of the probes but would need to look. The probe is basically a platinum coated wire wrapped around a short plastic stick with a led weight.
Boat is connected to shore power and sitting in water for 24 hours. Connect the Negative meter lead to Bat. Lower Positive probe from meter into and close by the drives. You want the voltage between numbers listed. To much or to little anodes attached to drive(s) will effect voltage, more is not better.
Fresh Water Areas -
620 - 1180 Millivolts with Digital Meter
Salt, Polluted or Mineral Laden Water Areas:
750 - 1180 Millivolts with Digital Meter
Boat is connected to shore power and sitting in water for 24 hours. Connect the Negative meter lead to Bat. Lower Positive probe from meter into and close by the drives. You want the voltage between numbers listed. To much or to little anodes attached to drive(s) will effect voltage, more is not better.
Fresh Water Areas -
620 - 1180 Millivolts with Digital Meter
Salt, Polluted or Mineral Laden Water Areas:
750 - 1180 Millivolts with Digital Meter
Here is a link to a great workbook about galvanic corrosion. I learned so much from this company and still reference their specs. Alldodge is correct, you will need a silver half cell connected to a multimeter to test for millivolts. You must also check that all underwater metals are bonded together. There are many reasons for galvanic corrosion.
