Per Page 2B-19 of the Nov. 2015 revision to the manual covering 3 and 4 cyl 2 strokers from 1994 up, The battery charging AC power from the stator (yellow leads) is applied to a full wave bridge rectifier in the rectifier/regulator module. One diode (half wave) rectification of the AC input is tapped off and sent to the tachometer. The only spec I can find is that it's 3v minimum, and consists of half wave rectified, sinusoidal pulses, so a DC meter would read the voltage. Max would be up around the peak value of of the AC input to the regulator. With 2 diode drops in the FWBridge and 14.5v max output from the regulator, this signal could peak out, at max RPM in the 15-18v range would be my estimation.
The manual lists 9 pickup coils wired in series for the battery charging part of the Stator. Since a flywheel magnet passes each in making one revolution, seems to me that 9 sine waves would be produced per engine revolution. So with that said, I would expect to see 9 half sine waves X number of engine revolutions as the frequency of that signal, if viewed on an oscilloscope type measuring device.
All speculation as I haven't had to cross that bridge in my years of engine ownership of this series of engines.
