Spending some quality time inspecting every part of your boat’s electrical system (that you can get to) can prevent an unsolved mystery on a “dark stormy night” later. This isn’t rocket science; it’s merely attention to a few details.
The Big Three
Marine electrical system troubles generally fall into three areas: Corrosion, Over-Current Protection, and Battery Maintenance. Let’s break them down one by one.
One of the most common problems is corrosion – specifically at buss bars, fuse blocks, and on the backs of switches – all of which are likely hideouts for corrosion. You can also find corrosion in light bulb sockets and bulb bases, so don’t forget to check those as well.
So what’s the solution? Keep those places clean and dry; an anti-corrosion spray can help a lot.
We recommend using Yamalube® Contact Cleaner in combination with a piece of emery cloth or small stiff brush to remove built-up electrical contact corrosion (make sure to turn off the battery first). Once the contacts and connections are shiny and clean, a shot of Yamalube® Yamashield or Yamalube® Silicone Spray Protectant & Lubricant will help keep these critical components safe from the elements for a long time.
#2: Over-Current Protection
(Fuses & Circuit Breakers)
Each circuit in your boat, if properly installed, should have a fuse and/or a circuit breaker to protect the circuit.
If a system or device fails, or a short-circuit occurs, there is the potential for too much electricity to flow through the circuit, creating the possibility of sparks, fire, and other undesirable outcomes. Fuses and fusible links have small gauge (size) wire in them, so if excessive current (amps) becomes present, the tiny wire in the fuse/fusible link will burn itself in half, thus not allowing high volumes of current to pass through and damage the circuit’s components.
Circuit breakers serve the same purpose – when extreme amounts of current reach the circuit breaker, a button pops up or a switch flips down, creating a gap in the circuit to stop the flow of current from the circuit breaker to the rest of the electrical system it’s protecting.
It’s important to know where the over-current protection is located for every circuit. Knowing where to look when a breaker trips or a fuse blows will make troubleshooting an electrical problem easier.
Circuit Protection Checklist
(Fuses & Circuit Breakers)
The check lists below will help you make sure your outboard’s fuses and circuit breakers are functioning properly.
Fuse Functionality (boat and engine)
- Turn the battery power off or remove negative (black, “—“) cable from battery.
- Visually inspect each fuse.
- Make sure the wire inside the fuse is intact.
- If the wire is broken, replace the fuse.
- Make sure fuse connections are clean.
- Remove chalky/rusty corrosion with an emery cloth, small wire brush, electrical contact cleaner, or pencil eraser.
- Check for fusible link continuity with a multi-meter
- Check the DC ohms setting (Ω)
Circuit breakers (boat and engine)
- Turn the battery power on.
- One at a time, turn on the device(s) that are connected to circuit breaker.
- If breaker trips (pops out/down), turn off the device(s) and check for an overloaded circuit or faulty device.
- If device(s) and circuit loads are good, turn the battery power off or remove negative (black, “—“) cable from the battery.
- Replace the circuit breaker.
#3: Battery Maintenance
This is important, yet not particularly difficult. Check the water levels in batteries and if they’re low, top them off with distilled water (on batteries with removable caps). Make sure the battery terminals are clean and tight. Also, have a good, reliable battery charging source.
Batteries Check List
Below are a few tips that will help you properly maintain the batteries on your boat:
- Check the fluid level in all of the cells (on batteries with removable caps).
- Top off the batteries with distilled water if necessary
- For all battery terminal connections, make sure not to use wing nuts.
- Stainless steel hex nuts are strongly recommended
- 5/16”x 18 coarse thread, and/or 3/8”x16 coarse thread nuts
- 5/16” and/or 3/8” stainless steel lock washers
- Keep your battery terminals clean.
- Use Yamalube® Battery Terminal Cleaner and Protector, and a stiff nylon or wire brush specifically made for cleaning battery posts and clean until bare metal is seen.
- Clean the cable connectors, as well.
- Apply a bit more Battery Terminal Cleaner and Protector or light grease to the battery terminals to prevent corrosion (dielectric grease works well).
- Ensure batteries are secured to avoid movement; check the straps/battery hold-downs.
More Electrical System
These tips are helpful and general for all marine electrical systems. Please refer to your owner’s manual or ask your local authorized Yamaha dealer for procedures specific to your particular boat and engine.
Charging System Check List:
- Turn the battery switch on, engine(s) off.
- Use a multi-meter set to DC Volts to check the voltage across the battery terminals. Make sure the reading is between 12 - 13 volts DC. If battery voltage is lower, charge the battery and recheck.
- If after charging, the battery still reads less than 12.6 volts, have battery load tested. Replace battery as necessary.
- Start the engine(s) and set the throttle to no more than 2500 RPM. Using a multi-meter set to DC Volts, again check the voltage across the battery terminals. The reading should be between 13– 15 volts DC. If lower, have the engine’s charging system checked by an authorized Yamaha dealer.
Lights Check List
- Turn the battery power on.
- Turn on each light separately.
- If a light doesn’t work, turn off the light switch and check the bulb individually.
- Make sure the internal wire filament is intact.
- If wire filament isn’t intact, replace the bulb.
- If wire filament is good, check for corrosion in the light socket and base of the bulb.
- Remove chalky/rusty corrosion with an emery cloth, a small wire brush, an electrical contact cleaner, or a pencil eraser.
- Reinstall the bulb.
- Turn on the switch.
- If the light still doesn’t work, check the fuse/circuit breaker.
- If the LED light doesn’t work, check the fuse/circuit breaker.
- If the fuse/circuit breaker is functioning properly, replace the LED device.
Make sure you always check your owner’s manual for specific information and any applicable warnings and cautions before beginning any work.
When it comes to your boat’s electrical system, attention to detail – and a bit of common sense – can keep things running well for years to come.
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