1987 merc 70 hp tach output

[Bmccart]

I have a 1987 merc 70 that I’m having issues with the tach with. At first the old tach didn’t work, bought a new one and it still didn’t work. Checked all wiring and everything was good and narrowed it down to the rectifier. Bought a new rectifier and the tach worked for about an hour then started working sporadically then quit completely again. All wires are good and connections are tight. Is there anything else to look for? Or anything that commonly shorts out the rectifier? Or any other place to hook the tach sender wire up?

any help is appreciated

thanks

 

[fastjeff]

Ha ha! Just went through this dance with mine. Switch the tach sender wire to the other post on the rectifier. Don't move the yellow wires--just move the tach signal wire.

Don't know why this should matter, but it does. Had to do it several times on my similar motors.

Jeff