1971 Evinrude 60 HP Tach. Trouble

[cluseau]

My tachometer pegs out whenever the engine is running, no matter what the rpm. It reads zero when the engine is not running. I recently purchased the boat. I checked the charging circuit and had to replace the rectifier. It now charges OK but the tach is out to lunch. The tach is connected to a red wire coming out of the throttle lever control box and is grounded to a black wire coming out of the same control box. Any help is appreciated.

 

[G. Patton]

Re: 1971 Evinrude 60 HP Tach. Trouble

Cluseau...... You didn't say if that tach is a OMC product, but OMC did manufactuer a two wire tach many years ago that was a inferior product that would fail in the manner you describe. Most of the tachs manufactuired now are four wire tachs and are wired from the tach as follows:<br /><br />Purple to 12v when the ign switch (key) is on.<br />Red to 12v when the light switch is on.<br />Black to any continous ground.<br />Gray to the gray wire at the instrument/engine wiring harness (leads to the rectifier assy).

 

[cluseau]

Re: 1971 Evinrude 60 HP Tach. Trouble

My Tach does not have any indication of who made it but it only has one wire going to it besides the ground. That leads me to believe that it probably is an original OMC Tach. I am going to try and replace it with something else. Thanks....