1984 75 horse merc

atticus3600s

Petty Officer 2nd Class
Joined
Sep 19, 2004
Messages
120
I have a 1984 mercury 75 horse outboard, and I am not sure the charging system is working and was wondering how to test it, also where should I look in the engine for the alternator? Also the tach is not currently woking and I was wondering how to make sure it is hooked up correctly.<br /><br />Thanks.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: 1984 75 horse merc

Sounds like all the symptoms of a blown rectifier, dead tach included. The alternator is built into the powerhead. The stator is under the flywheel. Two yellow wires lead from that to the rectifier. The tach signal comes from either of those wires. If the rectifier is bad, it won't charge the battery or send a tach signal. In most cases, crossed, corroded, or loose battery connections are to blame. If you have a voltmeter, the voltage should rise at the battery with increased RPMs.
 
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