COLOUR CODES FOR MERCURY MARINER OUTBOARD 8PIN WIRING LOOMS
Black with Yellow Stripe Wire - Engine Stop/Kill.
When this wire is earthed, it stops the engine. There may be more than one switch on tiller control models that connects to this wire.
For Example: The Engine Safety Kill Switch has one wire attached to earth and another attached to the Black/Yellow Stripe Wire, Should you fall from the boat taking your Safety Lanyard with you, when the lanyard disconnects it either releases a switch to make contact or pulls a switch down to make contact. When this switch makes contact it connects this Black/Yellow Stripe wire to earth which stops the engine.
Yellow with Red Stripe Wire - Engine Start
When this wire is supplied with a positive charge it triggers the Starter Solenoid which in turn supplys 12 Volts to the Starter Motor to turn the engine over.
Yellow with Black Stripe Wire - Engine Choke/Prime
When this wire is supplied with a positive charge it opens the valve on the Choke Enrichener or Creates a Electro-Magnetic field and engages the Mechanical choke mechanism.
TAN Wire (Occasionally Tan with a blue stripe) - Warning System
This wire is connected to the Warning Horn, The warning horn has a constant 12V Feed from the purple wire (Ignition Live) whilst the engine is turned on, if a Temperature Switch or the Oil Level Sender makes contact due to the engine overheating, oil too low or simply a faulty sender the horn will sound.
Purple Wire - Ignition Live
This wire is the Ignition Live, it supplies 12Volts with the Ignition Switch in the On Position, it supplys the warning horn and dashboard gauges.
Grey Wire - Tachometer Signal
This wire is the Sender (AC) For the Tachometer (Rev Counter)
Black Wire - Earth (Neutral)
This wire is Connected to the Engine Earth / Battery Negative.
Red with Purple Stripe Wire - 12V Positive
This wire is connected to the 12V Positive Supply from the Battery
Light Blue with White Stripe - TRIM UP Switch
This wire supplies positive to the Trim Relays when the Trim button is pressed up on the control box handle
Green with White Stripe - TRIM DOWN Switch
This wire supplies positive to the Trim Relays when the Trim button is pressed down on the control box handle

