Want to add a tach to my 98' merc, 2-stroke. Remote model with the charging system. Has the plug hanging out the back of the control box. I know the control box it hooked up correctly (rigged at factory) and by visual inspection. Question is.......what kind of marine tach would I need. Would I just buy one and go, or is there a spcific type I need. Also I need the pigtail that runs from the control box to the tach. If I buy the merc pigtail does it tie into the wiring harness that coms with the tach? Any info would be GREATLY appreciated. Thanks!