boat wiring diagram

Discussion in 'Outboards' started by mountainmn, Apr 11, 2010.

  1. mountainmn
    Joined: Apr 2010
    Posts: 1
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    Location: illinois

    mountainmn New Member

    looking for the wiring diagram for an 1987 Ozark, lakewood 17ft outboard motor boat with a 40hp mercury meriner 1987 motor or how it should be wired.
  2. kenJ
    Joined: Jul 2005
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    Location: Williamsburg, VA

    kenJ Senior Member


    boats of that size have a very simple wiring system. The lack of replies is because a diagram probably does not exist. If it has a battery, then there is probably an alternator/generator on the engine to charge it. Simple charging circuit. There is probably a key start, that too should be simple to sort out. Most of the wiring for the engine should come through a harness plug or two. Check on line with the engine manufacturer for that info. Lights, fuel level, any instruments are probably wired through the ignition switch. VHF/radios are should be wired direct to the battery through a fuse/circuit breaker.

    Hope that helps
  3. tunnels

    tunnels Previous Member

    Just draw yourself a wiring diagram and work it out youself . Start off with all the electrical things and then do you diagram . Think simple and easy . :confused:
  4. cummingknives
    Joined: May 2010
    Posts: 12
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    Location: Cedar Crest

    cummingknives cummingknives

    As seen elsewhere on this site, replies often miss the point conveyed in a question, and seem to be the go-ahead for expressing shortcomings rooted in the respondent's perception of humor. All this chap asked for was advice.

    As has been alluded to, small boat wiring is very simple even when there are numerous appliances (navigation lights, cockpit illumination, etc.), that require 12-volt power. A few simple technical things to consider prior to running wires is to determine if the environment in which your boat will operate is primarily salt or fresh water. If salt water, the requirements are slightly different because there are specific types of conductors (wires) recommended for salt water applications as opposed to fresh water.

    Regardless the environment, any wiring should be run in wire "loom", a corrugated flexible PVC tubing that is split along its length to facilitate its use. In addition, there are a variety of methods of "hanging" the wiring to keep it hidden away from traffic in the boat, and isolated from exposed features such as metal fasteners (nuts, bolts, screws, etc.), as well as railings, rod holders and similalr items.

    In salt water environments, stainless steel and nylon fasteners score way above carbon steel, or aluminum that is held in place by stainless steel. Where two dissimilar metals come in contact with each other, electrolysis begins immediately. This phenomenon will eat itself until it disappears, hence the requirement for "sacrificial annodes". These are primarily zinc fittings that are intentionally installed at various points below the water line so that they, not the boat or its components, are sacrificed (allowed to corrode).

    Since most wiring contains copper, setting up electrolytic condition can occur when two dissimilar metals are in close proximity to each other. In other words, the two metals don't actually have to touch each other. The water, or moisture, acts as a "bridge conductor" that allows current to flow thus causing (a) unintentional battery drain, and (b) corrosion of components and surrounding mounting surfaces.

    As to actual circuits, I prefer "home runs", meaning a positive (+) run from the battery source to the control switch, to the appliance, and a negative (-) return to the ground side of the battery. This describes one simple circuit. There are a multitude of ways, however, to accomplish the same thing without having a jumble of wires running out from the + terminal and a corresponding jumble returning to the - terminal. A better idea is to provide a simple circuit distribution panel (or a plastic box with numerous terminals in it to which you can connect shorter cables to various switches, and appliances, and return to a ground terminal (called a buss), in the box. If you're not familiar with electrical circuits, you have two choices:

    1. Obtain a book that describes how electricity works and how to configure simple circuits, or,
    2. Have your boat electrified for you by a competent technician.

    Doing the job yourself depends on (a) your level of understanding of what you read, (b) your self-confidence, and (c) your ability to follow directions. If any of these are absent, you're at the mercy of a "tech" who may or may not have the requisite qualifications. Most don't but some do. The trick is to discern the difference and weed out the good from the bad.

    In marine applications, the theory is similar to, but not the same as, house wiring. To begin with, most small boat applications depend on 12 volt DC power. DC = Direct Current. This means that there is no fluctuation relevant to AC (Alternating Current = house electricity that you buy from your local power company). A battery stores X amount of volts, usually 12, of power (also called "current") inside it, that is carried away from and returns it to the battery via a pair of wires (+ and -) to the appliance (light, switch, etc.), back to the battery thus "completing" the circuit. If either of these conductors is not present, there is no circuit. This condition is referred to as an "open" (not to be confused with a "short"). In order for an appliance to operate, three conditions must be present: (a) power (meaning a charged up battery), (b) a positive conductor (that carries live current away from the battery to the switch, and from the switch to the appliance, and (c) a negative conductor that connects to the negative (ground) side of the appliance and returns directly to the ground (negative) terminal on the battery.

    This is not rocket science, but absent a clear understanding of it, you can blow your boat up or burn down the entire marina to which it is moored. Since there are only two wires, and these are black (power), and white (ground), it is relatively simple to create a working circuit. What is difficult for some people to master is to plan the project carefully, obtain the correct components, and take all the time required by you to get professional results. If you are unsure how to proceed, or do not wish to invest in the simple tool available everywhere, or are intimidated by the process, leave it alone and contact a professional.

    And remember: Electricians are not cheap, but they charge less than undertakers.

    Good luck.
    Last edited: May 27, 2010
  5. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Cummingknives, are you a lawyer?

    Your post is longer than the wiring for mountainmn's boat. He asked his question more than 6 weeks ago and never responded, so I guess he found his answer elsewhere.

    And do they really use black for + and white for - in Cedar Crest?
    A large majority on this planet uses red for + and black for -, very confusing....
  6. Obsession
    Joined: Jan 2010
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    Location: Chicago, IL, USA

    Obsession Junior Member

    I haven't seen a boat that uses residential AC black + white - coloring for DC wiring!? That is going to cause some confusion on the water where black = negative. Or is this different in other parts of the world ???
  7. Bglad
    Joined: May 2010
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    Location: Jacksonville, Florida

    Bglad Senior Member

    Marine DC wiring color code red=positive, black or yellow=negative, green or green with yellow stripe=grounding

    From ABYC Table XIII

    There is also a table for color coding items commonly found aboard boats but I am not up to speed posting that kind of stuff here yet.
  8. cummingknives
    Joined: May 2010
    Posts: 12
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    Location: Cedar Crest

    cummingknives cummingknives

    Many thanks guys. I stand corrected with humility. I appreciate the tips very much. My only expertise is in amateur gynocology.
  9. tunnels

    tunnels Previous Member

    Black is the same the world over in every place iv been in !!.
    Tahiti we had only female plugs ! Twist the wires , push it in the slot and use a match stick to hold the wire in the socket , Worked every time !!!
  10. cummingknives
    Joined: May 2010
    Posts: 12
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    Location: Cedar Crest

    cummingknives cummingknives

    Okay, having said that what is your comment regarding DC wiring on trailers?
  11. cummingknives
    Joined: May 2010
    Posts: 12
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    Location: Cedar Crest

    cummingknives cummingknives

    You guys are getting on my last nerve about this. After being admnonished about wire colors, I labled all my wiring in my 14' runabout as follows:

    Black = Negative
    Red = Positive

    I used one color of tinned wire for all circuits to which I applied red or black tape on each end of every run, and gave each positive conductor a terminal number.....just like they do in residential applications. I don't really give a rat's *** if it's right or not because it will never be inspected by a licensed marine electrician, and each and every circuit is isolated and controlled by a UL approved toggle switch for wet applications. And all conductors are contained in non-conductive wire loom. Anyone who is color blind would be able to easily figure out what goes to what, how it operates, and be more than confident that it won't start a fire or launch itself into the air. For those who really care what I think about wiring tutorials, you've obviously mistaken me for someone who gives a hoot about your opinions on this subject. Here's the bottom line: It works, won't start fires, cause explosions, or electrocute anyone or anything.
    Last edited: Jul 14, 2010
  12. mark775

    mark775 Guest

    "As seen elsewhere on this site, replies often miss the point conveyed in a question, and seem to be the go-ahead for expressing shortcomings rooted in the respondent's perception of humor. All this chap asked for was advice."

  13. tunnels

    tunnels Previous Member

    If you use the proper plugs and the proper cable its all there in writing what colored wire goes where and what the colors are for .
    The packet the plugs come in have the code numbers plus colors and what they are for .
    Have just bought another car and done all the wiring for my Boat trailer !!
    I usually fill the inside of the plugs (both ends ) where the wire and terminals are with crease . keeps the water out , stops corrossion, and makes it easy to change a plug if it ever gets damaged for any reason !!:p
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