Help with rectifier (tach problems)

propwash

Seaman Apprentice
Joined
May 10, 2003
Messages
36
I have a 68 merc 650 and the tach just dropped out on me,nothing at all,so i'm thinking of replacing the rectifier as my searches on here lead me to believe this is the culprit in many tach problems,what i need to know is the rectifier that little green block with 3 terminals on it?the rectifiers i look up online don't look nothing like this piece.<br />also there is a little orange block of some kind attached to the back of my tach,does anyone know what that is?cause i got one dandy of a shock from it when i touched it with my wet hand when the motor was running,(dummy me).<br /><br /> PROPWASH.
 

erniex

Petty Officer 3rd Class
Joined
May 26, 2004
Messages
93
Re: Help with rectifier (tach problems)

Yes, the green block is the rectifier - old style. Newer ones are smaller and square or diamond shaped. The newer one will work the same but you may have to fiddle with the mounting as this won't match up.
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: Help with rectifier (tach problems)

The 68 mercurys came with a tach that was drive of the switch box not the alt. so check to see if you have a brown wire on the 4 post side of the box running the tach
 
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