Intermittent tach problems 78 OMC

28sstony

Seaman Apprentice
Joined
Aug 25, 2008
Messages
32
I reccently rigged a 78 150 Johnson on my boat and the tach didnt work, I replaced the rectifier and it worked for a while. Now it works about half of the time, sometimes ok, sometimes the needle is jumping around.

The harness and wiring is 100% new, the rectifier is new but the guage looks to be original to the boat (78), could there be any other possible problem than the guage being bad?
 
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