I have a 1987 Force 85 H.P. motor, and I'd like to add a dash mounted temp. gauge, could I use the existing sending unit or is it just an on/off type unit, if the sending unit is not workable, what type of variable voltage sending unit would work, the color of the existing sending unit is redish/orange, the reason I want to change this out, is with a buzzer, it will alway come on when the damage is done