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Marine Wiring Color Codes

This article documents the color codes for wiring used in marine electrical applications. Information is available for:

Boston Whaler Boats

Table 1 shows the color codes of wiring used in Boston Whalers. "Base" means the color of the wire jacket. "Stripe" means the color of an identifying stripe in the wire jacket. Color codes are listed as Base/Stripe, thus "Blk/Brn" means a black wire with a brown stripe. (It is believed that this color code is a standard used throughout the boat building industry.) Many electrical items are added after delivery, either by the dealer or the owner, so it is reasonable to expect that not all wiring found on a boat will conform to this standard.

Table 1. Boston Whaler Wire Color Code for DC and Special Circuits, after a similar table from Whaler.
No.Base/StripeIntended Usage
01Blk/BrnPump Grounds
02Blk/RedVoltmeter Grounds
03Blk/OrgIsolated Accessory Grounds
04Blk/YelBlower/Power Ventition Ground
05Blk/GrnWater Level Sender Ground
06Blk/BluLighting Grounds
08Blk/GryNav Light Grounds
09Blk/WhtBattery Parallel Solenoid
11BrnPumps-General, Bilge or Sump (Manually Switched)
12Brn/RedPumps, Bilge or Sump
13Brn/OrgPumps, Fuel/Oil Tranfer or Priming
14Brn/YelBaitwell or Aerator
15Brn/GrnFresh Water Pump/Water Maker
16Brn/BluHead Pump
17Brn/VioWashdown Pump
19Brn/WhtTemp Sender-Eng., Trans., Air., etc.
22RedBattery Feeds
27Red/VioMisc. Accy. Main Feed
29PinkFuel Sender
30Org/BlkAudio System Feed
31Org/BrnElectric Head-Sanitation System
32Org/RedWiper Port
34Org/YelDiesel Pre-heat
35Org/GrnWiper Stbd
36Org/BluCommunications Equipment
37Org/VioNavigation Equipment
39Org/WhtWiper Center
42Yel/RedStart Solenoid, Neutral Safety
43Yel/OrgPowered Ventilation, Fans
44YelBilge Blowers
49Yel/WhtRudder Angle Sender
52Grn/RedStop Solenoid/Kill Switch
54Grn/YelAC Grounding
59Grn/WhtWater Level Send / Water Pressure Send
60Blu/BlkCabin Lights
61Blu/BrnOil Temp Send
62Blu/RedCabin or Cockpit Lights Port
63Blu/OrgEngine Room Lights
64Blu/YelLighting Circuits to Remote Send
65Blu/GrnCabin or Cockpit Lights Stbd
66BluInstrument & General Lighting
67Blu/VioCourtesy, Boarding Lighting
69Blu/WhtOil Pressure Send
72Vio/RedEng. or Generator B+ from Breaker
74Vio/YelI/O Trim Up
75Vio/GrnI/O Trim Down
77VioIgnition-Generator or Engine
79Vio/WhtTrim Guage Send
80Gry/BlkMast Light
82Gry/RedSpotlight Remote
83Gry/OrgDocking Lights
85Gry/GrnStrobe or Beacon
86Gry/BluSpreader/Flood Lights
88GryNavigation (running) Lights, Tach. Send
89Gry/WhtAnchor Light
91Wht/BrnTemp. Alarm or Indicator
92Wht/RedFuel Alarm or Indicator
93Wht/OrgFire Alarm or Indicator
94Wht/YelAir Flow Alarm or Indicator
95Wht/GrnWater Press/Flow Alarm or Indicator
96Wht/BluOil Press Alarm or Indicator
97Wht/VioVoltage Alarm or Indicator
99WhtGeneral Alarm Usage, Yamaha Kill Switch

This information comes from Boston Whaler via Mike Williams. A PDF file version of this chart is also available.

OMC Outboard Motors

The following color coded wiring is often seen in outboard motors manufactured by OMC. This information was developed by Jim Hebert from factory wiring diagrams. Unfortunately, these diagrams are completely lacking in annotation. The identification of the circuits involved was deduced by the author with the assistance of OMC master mechanic David Zammitt of Lockeman's Boat and Hardware.

A pictorial diagram of the typical OMC ignition switch wiring is available in a separate article. It illustrates the use of these wiring colors.

OMC Under-cowling Wiring

(Based on V6 c.1992)

RED = Battery positive
RED with VIOLET stripe = Fused battery supply to ignition switch

BLACK = Battery negative
BLACK with YELLOW stripe = KILL Switch (grounded to stop engine)

YELLOW with RED stripe = START (Ignition switch to starter solenoid via safety switch)

VIOLET = Battery voltage in RUN or START  from ignition switch
VIOLET with WHITE stripe = PRIMER solenoid

LT BROWN = ALARM (grounded on alarm)

GRAY = TACHOMETER pulses to gauge from Rectifier/Regulator

OMC Stator Coil / Timer Base Wiring

YELLOW / YELLOW with GRAY stripe = Battery Charging Coil AC voltage
                                   to Rectifier/Regulator Assembly
                                   on Engine Block

BROWN / BROWN with YELLOW stripe = Charge Coil to Ignition Power Pack
BROWN / BROWN with BLACK stripe  = Second Charge Coil to Ignition Power Pack

ORANGE / ORANGE with BLACK stripe = Power Coil to Ignition Power Pack
                                    or OIS Module

Green / Violet / White            = Timer Base to Ignition Power Pack
/ Black with White

OMC Power Trim and Tilt

RED = Battery positive
RED with VIOLET stripe = Fused battery supply to remote controls

BLUE = UP supply to MOTOR
BLUE with WHITE stripe = UP RELAY
RED with WHITE stripe = Fused battery to remote switches

BLACK with TAN = Trim SENDER isolated ground
WHITE with TAN = Trim SENDER isolated fused battery positive

Evinrude E-TEC Outboard Motors

The following color coded wiring is often seen in E-TEC outboard motors manufactured by Evinrude. Where two colors are given the first is the main color of the wire insulation, the second is a color stripe identifier. For example, Yellow/White means a wire with Yellow insulation with a White identifier stripe. This information is also available in a color chart.


Yellow, Yellow/White = Phase 1
Orange, Orange/White = Phase 2
Brown, Brown/White = Phase 3

System Check

Gray = Tachometer
Tan/Orange = Check Engine
Black = Ground
Tan/Blue = Signal or Alarm
Tan/Black = Low Oil
Tan/Yellow = No Oil
Tan = Overheat

Key Switch

Black/Yellow = Stop Circuit
Yellow/Red = Start Circuit
Black = Ground
Violet = Switch B+ 12-volts
Red/Violet = Fused B+
Black/Orange = Bootstrap


White/Red = 55 Volt
Black = Ground (NEG)
Red = 12 Volt (B+)
Brown/White = Starter Solenoid (V-Models only)

Sensor Inputs

Red = Sensor 5V Supply, TPS, Oil, Water Pressure
Black = Analog Ground
Pink = Water Pressure CANbus
Pink/Green = Water in Fuel
Pink/Black = Cylinder Head Temperature
Pink/Blue = Intake Air Temperature
Tan/White = Oil Pressure
Green = TPS (Throttle Position Sensor)
Yellow = CPS (Crankshaft Position Sensor)
White = CPS


Red = CAN Source (voltage)
Black = CAN Common (voltage)
White = CAN High (data)
Blue = Can Low (data)


Orange/Blue = top
Orange/Violet = center
Orange/Green = bottom

Fuel Injection

Blue = top
Violet = center
Green = bottom


Red/White = Fuel (90° V6 Models 2008 and newer)
Violet/Black = Fuel (V4 and V6 Models)
Brown = Fuel (Inline Models)
Blue = Oil


Blue/Red = Water Valve - 55 V (Inline Models)
Red/Violet = Exhaust Valve - 12 V (V4 Models)
Black = Exhaust Valve - Ground (V4 Models)
Violet/Black = Exhaust Valve (V4 Models)
Blue/Black = Exhasut Valve (V4 Models)

Trim & Tilt

Blue/White = Up
Green/White = Down
White/Tan = Sender

Mercury Outboard Wiring

The following color coded wiring is often seen in outboard motors with the Mercury or Mariner brand. This information was provided by Mercury Marine.

Table 3. Mercury/Mariner Standard Outboard Wiring Color Code, after a similar table from Mercury Marine.
BlackAll Ground
BrownReference Electrode MerCathode System
OrangeAnode Electrode MerCathode System
Lt. Blue/White StripeTrim UP Switch
Lt. Green/White Stripe Trim DOWN Switch
Brown/White StripeTrim Sender to Trim Gauge
Purple/White StripeTrim "Trailer" Switch
GrayTachometer Signal
Black/Yellow StripeShorting or Stop Circuit
PinkFuel Sender to Gauge
RedUnprotected Wire from Battery
Red/Purple StripeProtected (Fused) Wire from Battery
Red/Purple StripeProtected (12 Volt +) to Trim Panel Control
PurpleIgnition (Switch) to 12 Volt Positive
TanTemperature Switch to Warning Horn
TanTemperature Sender to Temperature Gauge
Tan/Blue StripeTemperature Switch to Warning Horn
YellowStarter Solenoid to Starter Motor
YellowStator to Regulator (Charging Circuit)
Yellow/Red StripeStart Switch to Start Solenoid to Neutral Start Switch
Yellow/Black StripeChoke (Enrichener System)
Green with Color StripeSwitch Box to Coil - Striped and Numbered
White/Black StripeBias Circuit (Switch Boxes)

Yamaha Outboard Wiring

This information was provided by secondary sources but is believed to be accurate.

BLACK         = Ground
RED           = Battery Positive; SW3 Oil warning red light V4
YELLOW        = Ignition ON 12-volts; Four-stroke lighting coil
BLUE          = Instrument lights; choke; choke circuit;
                Ground potential oil transfer; High speed Charge Coil
GREEN         = Tachometer signal; lighting coil lead; knock sensor
ORANGE        = Trim position sensor
PINK          = Oil and overheat signal ground
WHITE         = Ignition stop circuit; SW1 oil transfer off position V4
BROWN         = Starter circuit; Low speed charge coil; Positive "+" potential
                to oil transfer pump; SW2 transfer on position V4
GRAY          = Warning circuit lead; Over-rev. control; Four-stroke tachometer
SKY BLUE      = Trim up
LIGHT GREEN   = Trim down
YELLOW/Red    = Diagnostic lead from ECU
PURPLE        = ECU groud to enrichment solenoid V76
BLACK/Yellow  = Thermo sensor
BLACK/Red     = Remote oil tank ground return, PBS to tachometer,
                Low speed charge coil
BLACK/White   = Ignition coil primary lead
GREEN/Blue    = Crank position sensor
GREEN/Red     = Red oil warning light ground through SW3 in main tank oil
                sensor to tachometer
GREEN/White   = Crank position sender; Lighting coil lead to rectifier
BLUE/Green    = Main tank oil level sensor SW2 oil transfer circuit
BLUE/Red      = Main tank oil level sensor SW3. No oil warning circuit
BLUE/White    = Main tank oil level sensor SW1; Oil transfer OFF circuit
BLUE/Yellow   = Shift cut switch
PURPLE/Red    = OX66 #1 injector
PURPLE/Black  = OX66 #2 injector
PURPLE/Yellow = OX66 #3 injector
PURPLE/Green  = OX66 #4 injector
PURPLE/Blue   = OX66 #5 injector
PURPLE/White  = OX66 #6 injector
RED/Yellow    = Key on power through fuel relay pump; power to ECU;
                Fuel pump and fuel injectors
WHITE/Red     = #1 pulser V6
WHITE/Black   = #2 pulser V6
WHITE/Yellow  = #3 pulser V6
WHITE/Green   = #4 pulser V6
WHITE/Blue    = #5 pulser V6
WHITE/Brown   = #6 pulser V6
YELLOW/White  = Electric fuel pump for electric carb system (ECS)

Honda Outboard Wiring

This information was provided by secondary sources but is believed to be accurate.

BLACK          = Ground
BLACK/White    = 12-volt power, Engine Start
BLACK/Red      = Engine Stop
BLACK/Green    = Stator, Ignition Coil
WHITE/Black    = Ignition Switched Power
GRAY           = Tachometer, Battery Charging
BROWN          = Choke
RED            = Temperature warning
Lt. GREEN      = Trim UP
Lt. BLUE       = Trim DOWN
BLUE           = Pulse Coil 1
BLUE/Yellow    = Pulse Coil 2
BLUE/Green     = Pulse Coil 3, 4

Comments or Questions

If you have a comment or question about this article, please append it to this message thread in the Small Boat Electrical discussion area.

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Copyright © 1999, 2000 by James W. Hebert. Unauthorized reproduction prohibited!

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Last modified: Saturday, 17-Apr-2010 13:34:21 EDT
Author: James W. Hebert
This article first appeared July 21, 2002.