79 Evinrude 200hp question on Voltage Regulator kit?

[70wellcraftV20]

I have a 79 200hp Evinrude and have this box that is mounted ontop of cylinder 1 above the starter coil I think it is a Voltage Regulator Kit but I am not sure and what does this do?<br />I see that some tach need this?<br />It conected to one of the yellow wires coming off of the stator and the other off of the red DC wire off of the rectifier. My question is do I need this it is not in the manual and motor runs fine without it.