I have a Mercruiser 470 that recently had some wiring problems. Now when I turn the ignition switch to "run" the tach pegs out. I know I had a bad ground earlier (fixed I hope), but I think I may have fried the tach. Is there a test procedure for checking a tachometer? The hook up is, I think, fairly standard. It has a positive hot terminal, a ground terminal, and a signal terminal coming from the coil.
