Here is a chart you can keep on the boat, but
I would rely on the wiring professional, if you don't know. Its like household wiring. Everybody thinks they can do it, but you always hear three words right after the news reports a fire- Fault Wiring Suspected. 
Talk to Sea Sparks. :thumbsup:
BIA Wire Color--------------------Where it is used
Black---------------------------------All Grounds
Black with Yellow stripe---------Magneto/short to Kill
Gray----------------------------------Tachometer signal
Yellow with Black stripe---------Choke
Red----------------------------------Unprotected(12V+)from battery
Red with Purple stripe-----------Protected(+12V)from battery
Purple-----------------------------(+12V)from ignition switch
Tan------------------------------Overheat sensor to warning horn
Pink-------------------------------Sending unit to fuel guage
Yellow with Red stripe----Ignition switch to starter solenoid
Yellow-----------------------------charging stator to rectifier
Lt.Blue with White stripe--------Trim up
Green with White stripe-----------Trim down
Some more standard wire colors used on many inboard boats, always double check though, as some vary or may have been changed along the way!
Some standard colors for boats since 1980 are as follows:
· heavy red 10 guage (main battery)
· heavy black (main ground)
· purple (ignition)
· yellow (starter solonoid)
· grey (tachometer)
· brown (temperature)
· blue (oil pressure)
· brown with stripe (alarm)
Accesories
· pink (fuel sending unit)
· yellow (blower)
· brown (bilge pump)
· grey (navigation lights)
· heavy green (bonding wire)
· red (misc electrical add-ons , vhf , depth finder, stereo, radar, power supplies)
