How to check tachometer on tracker boat

[liketofishalot]

I have bought 2 manuals for my merc 2002 50 HP motor none show me how to check tach not working I know the grey wire is connected to the motor and meter. Can I apply a signal to the meter to check it and what signal should be coming out of the regulator?

 

[Silvertip]

The tach needs 12 volts on the "I" terminal with the key ON. It must also have a good ground. The engine has a 12 pole stator that produces 6 complete alternating current pulses per engine revolution. If you have a signal generator you can do the math for whatever rpm you want to verify.

 

[liketofishalot]

Will test and let you know the results