1974 Sea Ray boat wiring issue
Here is a boat wiring inquiry from a Easy Ac/Dc reader with a 1974 Sea Ray.
Kevin,
I have recently purchased a 1974 Sea Ray boat, it is 22′-9″ long, inboard/outboard with a rebuilt Ford 351 engine.
The engine has not been wired to the ignition. I cannot get fire from the coil, although the engine turns over and I have power from the ignition “purple” wire to the positive side of the coil. The boat has points and a coil with an internal resistor. I cannot even get spark form the coil to the block never mind the plug wires at this point.
There are two wires from the boat wiring harness that are purple (one purple and one purple with a white stripe), I have tried it with them both hooked up and just the purple. I do not see a neutral safety switch wire from the boat harness. I currently do not have any of the gauges/trim hooked up.
I am at a loss, any help would be greatly appreciated!
Sincerely,
Roger – New boat owner
Roger,
Usually the purple is the ignition wire and the purple/white is the trim position wire.
- First I would eliminate the entire boat wiring from the system. Something as simple as a shorted out tach lead will cause your problem.
- Eliminate any ignition interrupters. I/Os in the 1970s had all these complex ignition interrupters to help stall the engine when it was shifted into gear. They usually were hooked to the negative side of the coil.
- Remove all extra wires from the coil. They are not necessary for starting.
Here is all the you need:
- 12 volts to the plus side of the coil
- Negative side of coil to points
Finally, as far as the safety stop switches are concerned:
Neutral safety switches usually break the yellow/red start wire. Emergency shut off switches usually break the ignition circuit. They are wired 2 ways:
- Type A – Ignition wire is broken before ignition switch – this makes all gauges and dash functions quit and it is obvious that the ESS has been pulled. They engine will no longer turn over.
- Type B – Ignition wire is broken after the ignition switch – this is easier to wire but is not as obvious when it is tripped. Gauges work and the engine will still turn over.
Hope this helps,
Kevin
Ground leads and polarity on battery charger installation
Steve wrote to us with a couple of installation questions about his battery charger.
Kevin,
I just bought a Guest Cruising Series 30 amp charger and the wiring diagram calls for individual ground wires routed to each battery bank.
My old charger had 3 positive leads to the battery banks and a single negative lead. The ground wires used jumpers between 1,2, and 3 banks so only one exit ground lead was necessary. This is how I would like to set up my new charger since all of that boat wiring is currently in place.
All of my battery banks are currently grounded together, but isolated by positive Will this work?
Steve
Steve,
You can certainly tie the 3 ground wires together since your system has a common battery ground. The new charger that you purchased actually has 3 separate chargers inside and is designed to work on a 12 volt, 24 volt, or 36 volt system.
Rather that trying to explain all the different combinations of connecting the charger, the manual says connect the charger directly to the battery.
Please make sure that your common ground wire is large enough to handle the entire 30 amps that the charger is capable of supplying.
Thanks,
Kevin
Kevin,
One more question…
I just installed my unit and I do not have access to the boat until next week. I realize now that I connected the AC connections backwards. The white wire is connected to “LINE” and the black wire is connected to “NEUTRAL” I also understand that AC is alternating, so it may make no difference.
Will I damage the unit with it hooked up like this? It worked fine when hooked up and didn’t notice that I did it wrong until I got home and looked at the manual.
Steve
Steve,
Connecting the AC wires backwards is common. It doesn’t really matter on the potted Guest battery charger. However, following the standard practice of Black is Line and white is Neutral will make it easier for anybody in the future to work on your boat.
Problems can occur on appliances that have their neutral (white) connected to their case ground (green). If they are wired backwards, the black wire in the outlet will be connected to the white wire on the appliance. If the white wire is connected to the case, then the circuit is completed through the green(ground) wire and the circuit breaker/fuse will hopefully trip.
Thanks,
Kevin
Installing inverter with Guest galvanic isolator
Here is a boat wiring inquiry from a reader who is concerned about adding an inverter into a marine electrical system that already includes a galvanic isolator.
Kevin,
I have a Guest 30 amp Galvanic Isolator I have had for a few years. I’m installing an inverter and plan to install the isolator. I’m looking for options on where I can install the unit. I’d like to install the unit after the inverter and near my AC and DC distribution panel and near the DC ground bus. Is this a possible installation location?
I have set my AC system up to feed 30 amps for AC power directly into the inverter and use the inverter AC out to feed the boats 110 volt distribution panel. I am using a Xantrex MS2000
Inverter/Charger.
Thanks in advance for your help.
John
John,
The best place to install the Galvanic Isolator is between the shore power inlet and the inverter.
The galvanic isolator is trying to prevent stray current corrosion by inducing a voltage drop between your boats DC negative system (Boat Ground) and the AC ground (green wire) at the dock.
The inverter probably has a circuit that connects the AC ground to the DC ground internally. If the GI is not between the inlet and inverter, then it will not be able to induce the drop required to block the corrosion.
Thanks,
Kevin
Affordable LEDs for Boaters
This morning’s New York Times published an interesting 
overview of the increased use of LED lighting in non-marine applications.
One part of the Times piece, which is an excellent read, looks at the dilemma faced by the lighting industry giants who…
…face a tough problem. Their businesses were built on customers who regularly replaced light bulbs. How do you make a profit when new lighting may commonly last 50 to 100 times as long as a standard bulb?
Even so, these bulb manufacturers…
…seem convinced that new lower-cost L.E.D. bulbs, with their improved efficiency, will eventually become the chief substitutes for incandescent bulbs in homes.
Still, the most obvious stumbling block to a widespread shift to from incandescent or fluorescent to LED light is the increased cost. And the differential isn’t slight…
…a standard 60-watt incandescent usually costs less than $1. An equivalent compact fluorescent is about $2. But in Europe this September, Philips, the Dutch company dealing in consumer electronics, health care machines and lighting, is to introduce the Ledino, its first L.E.D. replacement for a standard incandescent. Priced at $107 a bulb, it are unlikely to have more than a few takers.
Luckily, for those of us who deal with boat wiring, most of our lighting is purchased as a part of a fixture and only occasionally as a stand alone bulb or, as we move forward, diode. This tends to help decrease the price increase for this great new technology. 
That is, while the light engine itself may be exponentially more expensive, once it is coupled with a, say, navigation light housing or cabin light fixture that price spread becomes considerably more palatable.
This is especially true of a dedicated housing for an LED. A marine electrical manufacturer might realize little or no cost gain by rigging an old fixture with an LED. But, when a light housing is designed from scratch for this application, a clever manufacturer may find any number of application efficiencies that can help to offset the cost of the light engine itself. Just one example of this would be the different design accommodations required for the heat dissipation between incandescent and LED fixtures.
A great example of this type of engineering ingenuity can be seen in all of the new LED lights recently introduced by Attwood. 
Building upon the inherent advantages of the new technology, e.g., extremely low power demands and heat output plus extremely long “bulb” life, the Attwood engineers designed their fixtures to stand up to the serious rigors of boating – including making each impervious to water incursion – while keeping aesthetics and surprising affordability as top priorities for each offering.
Attwood is incredibly bullish about the future of LEDs in boating. Other marine vendors have dabbled in LED, with an occasional – and usually expensive – LED fixture added to their existing incandescent product offering. Not Attwood. In just the last year, they have introduced the marine industry’s most comprehensive line of LED lighting, including both one-mile and two-mile navigation lights, all-round lights, cabin lights, strip lights, courtesy lights, docking lights, and underwater lights. And each, without exception, is an excellent value given its advantages over the incandescent that it obsoletes.
Troubleshooting a Mercury breaker overload
This came in from one of our readers last week:
Hi Kevin:
I am having an electrical problem with my 2006 Mercruiser 4.3L TKS 190HP I/O. The problem is that the 50 amp circuit breaker for the Overload Electrical System keeps popping every time the engine is put into med-high RPMs.
I have tested the battery, checked all wires, wiring harness, etc., all everything looks normal.
Any idea what might be causing this breaker to pop or where can I begin troubleshooting?
Thanks, Andy
Andy,
In 2006, Merc made a major change as to how their electrical system connects to the boat’s wiring harness. Instead of running the entire boat’s electrical supply through the engine harness, boat builders were supposed to run a secondary power harness supply all non-engine related functions.
At mid-high RPMs, the alternator is putting out it’s max current and max voltage. Something very simple is pushing the system beyond the 50 amp max.
Voltage = current x resistance. The resistance of the items on your boat do not change. As the voltage goes up, the current will go up.
It is possible that the power trim pump is causing the breaker to pop. Under load, the pump has the ability to draw 75 amps. If this is connected to the starter end of the red battery cable, it is possible to have the alternator try to supply the entire 75 amp demand and pop the breaker.
Troubleshooting:
- Begin disconnecting items that are powered through the ignition/engine to stop the breaker popping. This could be as easy as removing fuses.
- Disconnect the power trim pump if it is wired directly to the starter.
- Add an additional power supply wire to the helm area. Install an ignition protected breaker or ATC fuse within 7” of where it connects to the battery.
- Connect the power trim pump power leads and ground to the battery.
Let me know if this helps or if you have any other questions.
Clever New Concept in Trolling Chargers
The Guest division of the Marinco Electrical Group has introduced a genuinely clever new concept in battery chargers that should be a huge hit with both fishing boat users and manufacturers.
By adding a voltage sensitive relay to Guest’s legendary potted charger technology, these new units don’t only charge both a boat’s starting and trolling batteries when connected to AC power – the traditional role of a trolling charger. The new Charge Pro Plus chargers also allocate the alternator’s output to both batteries – while the boat is underway.
As Guest explains…
The new Charge Pro PLUS system combines a Guest charger with an alternator power module (VSR) to continuously charge the trolling motor or house battery while the engine is running.
This one-of-a-kind system allows energy which is normally wasted on a fully charged cranking (or starting) battery bank to be re-directed to the trolling motor or house battery bank – ensuring that all batteries are fully charged.
The 12V and 24V VSR modules are rated for alternator charging systems up to 70 Amps.
The benefits of this new approach to DC power management include
- Continuous charging of trolling battery whenever the boat engine is running
- Extension of fishing time, keeps fishing boats on the water longer
- The harnessing of previously unused or wasted alternator power for trolling use
- Increased longevity of expensive trolling batteries
The real-world gains that fishermen will realize from this new system to fishermen are impressive. A 70 amp recovery should translate into one additional minute of trolling for every minute running across the water. This will make the unit a very attractive add-on to the builders of fishing boats – many of whom are searching for new features to jump start sluggish sales.
While this sort of all-inclusive DC power management has been attempted previously by others in the marine industry, the products offered were either seriously underpowered or prohibitively expensive – or both. Neither is the case with the new Guest chargers.
Guest’s initial offering of these innovative new chargers will include units with dual 4 amp and dual 10 amp outputs. Either configuration is available for either 12 volt or 24 volt systems.
For more information on these chargers, please visit Marinco’s gorgeous new website at marinco.com
Adding a Second Alternator
Noted marine author, Scott Fratcher, has generously allowed us to post his comprehensive article on the addition of a second alternator to an inboard boat’s electrical system.
Mr. Fratcher’s highly regarded books include
- How to Make Money with Boats
- Metal Boat Repair and Maintenance
- How to Buy Your Cruising Boat Now
- Earthrace – First Time Around
Mr. Fratcher also has an excellent website that is highly recommended to all easyacdc.com readers. Please be sure to visit Team Yachtwork and thank him for his thoughtful generosity.
