I`ve got a water pressure gauge for my 04 mercury 75hp 4-stroke. Gauge only what all do I need to hook this up and too were on the motor ? It has 2 terminals on the back does it matter which 1 is hot & ground ? There`s also a fitting for a hose which I quess will run to the motor ? If you sell a installation kit Don with instructions that would be great. Any and all help is appreciated thanks bbc friends, David Garner