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1995 BF75A accessory wiring help needed

C

Cretster

Contributing Member
Hi

Finally after rebuilding the transom of the boat I bought in Feb this year I have the engine bolted on at last.
I need to now create the wiring but am a little unsure what's needed in terms of wiring to the console.

I have 4 gauges -

Honda Tacho (analog)
Honda trim/tilt (analog)
Faria Volt meter
Unbranded Fuel gauge

The fuel gauge of course has its own separate sender so I can forget that for now
There is a spur of wires that comes off the harness from the ignition/throttle control box and it has these wires:

photo-138.jpg


Not sure what each one is, but I'm led to believe that the wiring harness has wires to provide signal & power for gauges.
Can anyone possibly clarify what each wires is in the pic above please?

Aside from the gauges themselves, I have various other things to run, so it would be really useful to know what current the feed through these wires is able to supply. That way I can determine what other items can be powered from this without the need for sending more wiring from the battery to the switch panel.

This includes things like fish finder/gps, vhf radio, nav lights, bilge pump (I'm certain this will definitely need a beefier power source, even if the other things don't!).
Somehow I can't envisage these items plus gauges and their illumination all coming from these little wires.


On another cabling related note, can anyone advise what the standard gauge/thickness/cross section (mm2) is that's needed as a minimum for the engine supply cabling? Ie the cable that goes from battery to engine?

I'm fitting an isolater key and a rotary switch for battery selection so I need to make up a series of short cables for this and am uncertain what cable I need optimally for this. Last thing I want to do is create problems by installing cables that aren't up to the job, so at least if I know what the minimum spec is then I can set that as a baseline for what to buy.

Many thanks!
Jim
 
The link gulfcoastsurf indicated is a good one. You can also download the owner's manual from the Honda website. It has the complete motor, wiring harness and gauge wiring diagram in the back of the manual http://marine.honda.com/pdf/manuals/31ZW0600.pdf

As far as tapping into any of the wiring harness....do not do it.

The engine wiring, harness and gauges should be separate from any of the other electronics on the boat...ie nav lights, horn, courtesy lights, depth finders, bilge pumps, etc.

You should run a separate pair of wires (at least 12 ga through a 25 amp circuit breaker) at the battery) to a fuse distribution panel under the dash. Some also act as a power buss. Then you can attach any other power item you need to the panel. Most panels have both a positive and a ground connection. If you need more power at the dash, then you have to run a bigger size wire with larger circuit breaker.

That makes things so much more clean and easy to troubleshoot in the future.

Never tap into the engine wiring.

The only place they both come together is the ground lug on the battery (or a ground buss).

Here is a link to a typical boat wiring http://newboatbuilders.com/pages/elect6.html

Wiring it right now, will provide you with many years of reliable boating.

Mike
 
Let me expand on Hondadude's excellent advice.

I would actually recommend running 10 gauge wires from the battery switch to your distribution bus because it seems that there is always a need for more power at the helm. Use the tin-coated marine grade wires that resist corrosion much better than the stuff you buy at the local hardware store. You can order through West Marine or Jamestown Distributors.

From the distribution bus, wire in a fused distribution panel for nav lights, interior lights, VHF, and all the rest of the stuff. Personally, I prefer the panels with the rocker switches and the barrel fuses that light up when the rocker switch is in the on position. They make it very easy to check and change fuses, and gives you a visual cue as to what is turned on. That also eliminates any in line fuses which can be a pain to troubleshoot.

Right above my distribution panel, I wired in a small simple red indicator light that tells me I have power coming to the panel. It's a reminder to turn off the battery switch before putting up the boat, or refueling.
 
Thanks guys - I've got the plan sorted out now after some thinking and working things out.

I figured it would help balance the weight distribution of the boat if I can shift some weight forward since there's a huge amount at the stern and only the fuel tank and me amidships to help with that.

So I'm going to situate the 2 batteries underneath the console, and run cables aft to the engine.
I think the normal outboard power cables are around 16mm2 (6 gauge), and I have a new set of jump leads that are 3.5m long and 41mm2 section which is 2 gauge that can very nicely run the power from console to stern without worrying about voltage drop etc.
There's a conduit that runs below deck for cables to get to the stern tidily.

This way the weight is more balanced (engine is about 170kg and aux is 28kg), and the power source is right underneath the devices that need it generally like the gauges & radio etc. So a small distribution block under the console will do nicely for feeding the 6 gang fused switch panel I have (illuminated covered rockers).

The 41mm2 section cabling is probably overkill since it'll be closer to 2m length once tidied & trimmed etc, but I already have it, and I'd rather have excess than not enough.

Have got the manual now thanks, and the wires at the remote box are actually clearer coloured here:
IMG_0723.jpg


So it's 4 wires really and I think they match up to the gauge connectors in the manual, so I can make a small harness for the gauges without coughing up £50 for the honda one.
 
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Well I've got a lot of it done now. The jump leads do a superb job as extended engine cables due to their thickness.
The starter cranks over really quick despite the cable being in total about 4.5m long!

So in terms of electrics I've got the following done in the last day or two:

Tacho working
Trim/Tilt hooked up (not working - think it's a dodgy sender)
Oil pressure light working
Fuel gauge working
GPS/Fishfinder working
VHF radio working
Port/Stbd lights working
Instrument lighting connected
Isolater key added in

Plus plenty of other stuff like bonding in the scupper flaps, the transom drain, drilling & filling for the aux engine bracket, changing the fuel tank filter, prepping the windscreen, running the engine a lot to test the water flow, fibreglassing back in the panels I cut from the deck to repair below it, etc etc etc
 
Definitely, thanks

Is there a way to test the overheat warning, without actually making the engine overheat? My telltale stream misbehaves at times and while I'm sure the water pump and impeller are fine, it'd be reassuring to know the overheat warning is going to work if I need it to!
 
Well, I have a 225, so I don't know if this is the correct procedure for your engine. Hopefully Mike or Jimmy will chime in. But here is how mine works.

There is a two-prong connector to the ECT (engine coolant temperator) sensor - one has a red-white wire and the other a green-red wire.

First, use an OHM meter to test resistence between the two wires coming from the sensor. On my sensor, I see about 5k ohms at ambient temperature (0 degrees C) and about 400 ohms at 75 degrees C. As the sensor heats up, resistence drops almost linearly.

Second, with key on and sensor sire disconnected, on the harnes side of the connector measure DC voltage from red/white wire to ground. It should be between 4.3V and 5.2V. Then measure voltage from red/white wire to green/red wire. It should read the same voltage.
 
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Appreciate the instructions thanks. Don't think that will help for mine alas as mine has a single red wire to the temp sensor so it's resistance between that and earth.

BUT, I did manage to speak to my engineer today, just as he was leaving the country for well deserved retirement!
He says I can test the alarm functions ok by just shorting the sensor wire to the block. Doesn't tell me if the sensor itself is ok or not, but I can check the resistance of it at different times and make sure it's changing with changes in engine temp.

He told me also re' weak telltale that I need to do backflushing through both the flush port on the back of the engine, AND if possible through the telltale, in order to help flush out bits of crud.

Ordered a new thermostat today as well since I don't think my one is closing properly.
Backup engine to bolt on tonight all being well. :)
 
Okay - so you have a straight resistence-type heat sensor. I actually installed two of those on each side of my engine block to monitor actual temperature. If you can find an old single wire marine heat gauge laying around some where, you can hook it up to that sender. Run a wire from the wire coming off the sensor to the "S" (signal) terminal on the gauge and run another wire from your engine block to the "G" (ground) terminal on the gauge. The gauge may not be matched to the resistence of the sensor, so the temperature reading may not be accurate, but at least you can check that the sensor is working under different ranges of temperature.
 
The temp sensor is a switch. It is either on or off. When the temperature gets to the point of overheat, it essentially shorts the wire to ground.

If you ground the wire with just the key switch on, the red light will come on but the horn will not sound. The engine has to be running for the cdi unit to sound the horn.

So your resistance measurements will be simple....either an open or closed circuit.

Mike
 
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