Heres something I copied from one of Tony's (Jetaholic's) Posts.

Helped me a LOT with Moo! Hope it helps you, Sam.

"So here I will post the marine standard electrical color code for jet boats:

Black - All grounds
Red - Constant hot (all wires that have 12 volts on them regardless of key switch position, "BAT" terminal on key switch)
Purple - Hot In Run (switched hot, controlled by key switch i.e. ignition, gauges, etc, "IGN" terminal on key switch)
White - Hot In Start (runs the starter bendix or aux solenoid)
Light Blue - Oil Pressure Sender; "S" terminal on Oil Pressure gauge
Light Brown or Tan - Water Temperature Sender; "S" terminal on Water Temperature gauge
Grey - Tachometer signal from ignition; "S" terminal on Tachometer
Orange - Bilge Pump hot from switch to pump
Pink - Bilge Blower hot from switch to blower
White/Red - Fuel level sender; "S" terminal on Fuel Level gauge
Yellow - Lights from switch to lights"

Ray

Thanks guys, this should work. My other concern is that I'm converting from Ammeter to Voltmeter. I'm thinking I can use the existing wiring, just change the signal source from alternator??? I can't remember, its been 10 years since the last time I did any major wiring lol.