If you don't have the pigtail for the tach hookup on your control box, it may be because your control box is a year or two earlier. On these earlier control boxes, the factory made provision for adding a tach. If you open up the control box, you will find the factory left a gray wire pigtail wound up inside the control box. There is a single hole on the under side of the control box where you can draw the grey wire end down and out of the box. That grey wire is the signal wire to drive the tach. Marine tachs are usually made in a universal configuration, so it should work. Just make sure the tach selector switch on the back is set to the correct number of poles on the alternator.
