I have a 1996 Tracker Targa with a 60hp Mercury. Yesterday I noticed a message that would occasionally flash on the screen of my fish locater. It would appear in a box in the middle of the screen and say "High Voltage". When I looked at the voltmeter on the dash it would be almost 18 volts. After a period of about 1-5 seconds it would go back to a little over 14 volts, this is where it usually is. Incidentally, the last couple of years my tach sometimes gives faulty readings. Could my battery be going bad? Mike