Bad Rectifier?

misdeal

Seaman
Joined
Jul 14, 2009
Messages
60
i have a 1989 120 hp johnson outboard,,,brand new marine battery last year, all connections are clean and tight, tach works, battery wont charge, voltmeter reads 11 volts at idle 12.5 volts at full throttle, then back down to 11 at idle, spent 8 hours on the water saturday and when i docked still read 11 volts,,,not sure if its the rectifier,,,do they go bad over time ? ihave never reversed the polarity which im told would kill it,,, would like to know for sure before i spend a 101.00 for a new one,,,,
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Bad Rectifier?

Measure AC voltage between yellows to the rectifier with motor at a fast idle. Should get => 30 VAC. If not, stator is bad (rectifier could be bad as well, but can't be absolutely sure until you know the stator is OK.
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: Bad Rectifier?

if the tach works the rectifier is working.
regulator might be shot but they usually go open (high).

Test the stator.

first get the factory manual.

www.outboardbooks.com
 
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