JTS357

Hey Everybody,
I am currently reviving a 87 SR1 that was used and abused by it's previous owner. I removed the original 420's rebuilt them, painted the engine well, reglassed the engine compartment bulkhead... blah..blah...blah. Anyway, when I reinstalled the engines I came across a 14 AWG green wire coming from Mercruiser "black box" in the forward wiring harness. I can't remember what the heck it does...The engines run fine without it but I just cant help thinking it must be there for a reason. Any help would be appreciated...and it's nice to be back on OSO.

jackhammer

My 'black boxes' have to do with that anti-corrosion stuff (can't recall the technical name atm). I don't have mine connected either... in fact it's in my shed! I don't keep my boat in the water so I don't worry about it.

This might help...

Standard Boat Wiring Color Codes.


Blk -Grounds-General
Blk/Brn -Pump Grounds
Blk/Red -Voltmeter Grounds
Blk/Org -Isolated Accessory Grounds
Blk/Yel -ignition stop
Blk/Grn -Water Level Sender Ground
Blk/Blu -Lighting Grounds
Blk/Gry -Nav Light Grounds
Blk/Wht -Battery Parallel Solenoid
Brown -Pumps-General, Bilge or Sump (Manually Switched)(Also alternator
starter to Ign.)
Brn/Red -Pumps, Bilge or Sump
Brn/Org -Power feed to Auto Bilge Switches-Pumps, Fuel/Oil Tranfer or
Priming
Brn/Yel -Baitwell or Aerator
Brn/Grn -Fresh Water Pump/Water Maker
Brn/Blu -Head Pump
Brn/Vio -Washdown Pump
Brn/Wht -trim pos sender
Red - Battery Feeds Unprotected
Red/Vio -Misc. Accy. Main Feed Protected (fused) from batt to trim panel.
Pink -Fuel Sender
Org/Blk -Audio System Feed
Org/Brn -Electric Head-Sanitation System
Org/Red -Wiper Port
Orange -Accessories common feed- Dist Panel to Acc switch-Anode
Electrode-Mercathode
Org/Yel -Diesel Pre-heat
Org/Grn -Wiper Stbd
Org/Blu -Communications Equipment
Org/Vio -Navigation Equipment
Org/Wht -Wiper Center
Yel/Blk -Choke - Neutral saftey trans mounted
Yel/Red -Start Solenoid(starting circut), Neutral Safety
Yel/Org -Powered Ventilation, Fans
Yellow -Bilge Blowers -(also alternator DC output)
Yel/Wht -Rudder Angle Sender
Grn/Red -Stop Solenoid/Kill Switch
Grn/Yel -AC Grounding
Green -Bonding
Grn/Wht -Engine Trim in and or tilt down
Grn/Org -Engine Independent Trim down
Blu/Blk -Cabin Lights
Blu/Brn -Oil Temp Send
Blu/Red -Cabin or Cockpit Lights Port
Blu/Org -Engine Independent Tilt Up
Blu/Yel -Lighting Circuits to Remote Send
Blu/Grn -Cabin or Cockpit Lights Stbd
Blu -Instrument & General Lighting
Blu/Vio -Courtesy, Boarding Lighting
Blu/Wht -Engine Trim Outand/or Tilt Up
Light Blue -Oil Pressure
Vio/Red -Eng. or Generator B+ from Breaker
Vio/Yel -I/O Trim Up (ballast bypass)
Vio/Grn -I/O Trim Down
Vio -12v Ignition-Generator or Engine
Vio/Wht -Trim "Trailer" switch
Gry/Blk -Mast Light
Gry/Red -Spotlight Remote
Gry/Org -Docking Lights
Gry/Grn -Strobe or Beacon
Gry/Blu -Spreader/Flood Lights
Gry/Vio -Windlass/Winch
Gray -Navigation (running) Lights, Tach. Send
Gry/Wht -Anchor Light
Wht/Brn -Temp. Alarm or Indicator
Wht/Red -Fuel Alarm or Indicator -((Ignition module to Dist.)Mercury
Thunderbolt Ignition)
Wht/Org -Fire Alarm or Indicator
Wht/Yel -Air Flow Alarm or Indicator
Wht/Grn -Water Press/Flow Alarm or Indicator - ((Ignition module to
Dist.)Mercury Thunderbolt Ignition)
Wht/Blu -Oil Press Alarm or Indicator
Wht/Vio -Voltage Alarm or Indicator
White -General Alarm Usage, Yamaha Kill Switch
Tan - Water Temp sender
Tan/Blu -Warning system sense wire (Audio warning)
Pink -Fuel sender

JTS357

Jackhammer,
So do you think it's a bonding wire for the mercathode?
And thanks for the info.
357

jackhammer

I went and looked... I have 2 green wires coming from the galvanic isolator. They're more like 8 awg though.

jackhammer

It was the big black box... probably 4x8x12. The little black boxes I didnt look at... but I think they have terminals only, no wires.

JTS357

OK so I'll assume since mine is the 4x8x12 box also...and it's buried any how and the mercathode system is crap anyway......I'll just tuck it away and forget it. Thanks