Can somebody tell what the actual difference is between a tach that is intended for an outboard motor and one that is intended for an I/O? Don't both types have a selector switch on the back for differing amount of pulses?
Generally speaking, ignition triggered with a switch for number of cylinders (I/O) or stator triggered with a switch for number of poles (O/B) and runs on the stator generated AC. There are variations, of course.
Well, it's styling plus scale. My original tach goes up to 6K rpm and the 100 hp Merc has a max rpm of 5250. All the outboard tachs I see for sale go up to 7K rpm. The I/O tachs go to 6K just like my old one. I guess it won't hurt anything to have a 7K tach. I just thought I'd ask.