Temp Gauge for merv 135 V6

[sloboat]

i have a 1994 merc 2 liter V6 outboard with a warning horn. i am buying a temp gauge. they sell as just the gauge or as a kit with the sending unit. Can i just hook a basic teleflex water temp gauge to one of the sensors in each head? I also have a brown wire coming from the helm that shows conductivity back to the sending unit. Can i use that wire?

thanks