I am running a 2004 Evinrude 225 HP HO DI engine. I had my boat winterized and took it out yesterday for it's 1st trip. I noticed that my tach was reading about 1,000 to 1500 rpm off. I was doing around 70 gps when i know i should be turning about 5500 at 70-72 gps. I checked the connections at the tach they seemed to be ok. Took the cover off the motor and looked for loose connectors etc but I don't really know where my tach would be coming from. I would imagine it would come from a coil or magneto but I know my engine is a bit more technically advanced then that. Thanks for any and all help.