Tach won't work

simbot

Cadet
Joined
May 28, 2008
Messages
20
Hi everyone I have just bought my second boat for the family its a older 70s trihull with a 1975 Merc 85hp motor, I had it running at home however wouldn't go at the launch. It turned out to be the cdi and the trigger, 900 bucks later I'm on the water finally. I read that the tach output is not on the new cdi unit so my factory tach just buzzes and is doing nothing can I get it to go again.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,030
Re: Tach won't work

Look under the wrap cowling. The tach signal is the brown wire. It needs to be connected to one of the yellow stator wires in order to power an aftermarket Tach. If you still have the old Mercury tach, they were powered by the switchbox, and if you do not have the brown terminal on the switchbox, you are out of luck. If so, spend the $60 and get a new aftermarket tach.
 
Top