my #2 spark plug wire came loose and sparked on the coil on my 4cly merc now tach wont work right but boat still runs perfect what does tach get the sig from
It's very easy to kill a tach. Once I had the ground wires on battery loose (on the brand new boat from marina!) and sparked enough to kill the tach. The replacement tach (warranty) was good only for a few months (with no sparks that I could find). But the third one was the charm.
