1988 Mercury 90hp

Schnidly

Petty Officer 2nd Class
Joined
Aug 12, 2001
Messages
143
Dear Forum,

I own a 1988 Mercury 90hp 3cylinder outboard, serial number 0B302485. I have a simple rectifier to charge my battery, no voltage regulator. Would it be possible to replace the rectifier block with a voltage regulator instead and if so which voltage regulator do I purchase, recommendations? PLEASE HELP. Also, when the rectifier turns on my voltage on my voltmeter in the dash goes up to around 15 volts and then drops down to 10 to 12 volts. I think this happens when I reach a certain rpm. Is this normal? Just replaced my 5 year old battery. Forgot to mention that my charging system is a 9amp system, the lowest mercury put out for my year and horsepower.
 

aussieflash

Lieutenant Junior Grade
Joined
Feb 5, 2011
Messages
1,004
Re: 1988 Mercury 90hp

Yes its normal for voltage to rise and fall with RPM as its not regulated.Mine peaks around 17V at WOT.
You can purchase a rectifier/regulator combo though not sure of PN.Im thinking any 12v regulator would work....but im no expert with electrics....been zapped too many times.
 
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