2001 225 Vmax problem

[Shamm]

I have a 2001 225 Vmax and the tach quit working. I replaced the tach and the new one does not work either. Dealer replaced the rectifier/regulator and tach still does not work. The wiring to the tach checked out ok, and I do have 12+ volts to power the tach. From what I can tell the tach signal wire comes from the CDI unit. So I swapped the CDI out with a friends, and still no tach. How is the tach signal generated on this engine? Could it be the crank position sensor? I have the manual but I don't have a way to measure the peak voltage of the sensor.
Thanks for any help
Shamm

[boats.net]

The tach is alternator driven check alternator output(lighting coil), the crank sensor does not have anything to do with tach signal.