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Author Topic:   Fuel gauge wiring and bonding wire 1973 Outrage
Raaaaay posted 05-02-2011 02:10 AM ET (US)   Profile for Raaaaay   Send Email to Raaaaay  
I am doing a complete renovation of my 1973 Outrage 19. I have installed a new fuel tank and am now ready to run the wire from the fuel tank sender and the bonding wire. I know nothing about boating electrical, so this needs to be "dumbed" down for me. From what I have read the positive wire from the fuel tank sender is to be pink and the negative would be black. The bonding wire is supposed to be green insulated wire of 10 gauge. Is that correct? [Does the bonding wire] run to the negative battery terminal? Where do these wires run to? What length of wire should I buy for this purpose?

My console and the boat was stripped bare, and there is currently no fuse panel, or terminal block or any switches. I want to run these wires so I can seal up the deck panel over the fuel tank, then I will get the motor installed and then probably hire someone to do the rest of the rigging and wiring.

jimh posted 05-02-2011 09:16 AM ET (US)     Profile for jimh  Send Email to jimh     
The bonding wire for the metallic fuel tank in a boat like an older Boston Whaler center console will typically connect with the other metallic components of the fuel system, such as the filler cap, and then connect to an electrode on the transom. If there is no electrode on the transom, the negative terminal of the battery can be used as a termination for the bonding conductors. The bonding conductors must not carry any current.

The fuel tank level sensor wires naturally have to connect to the fuel tank level gauge, wherever that gauge happens to be located in a particular boat. Some sensors have an isolated terminal for the negative and some use the tank itself as the negative. In either case a separate conductor should be run to carry the current from the sensor back to the gauge for the negative portion of the circuit, so as to keep the current from having to flow on the bonding conductors.

Raaaaay posted 05-02-2011 12:35 PM ET (US)     Profile for Raaaaay  Send Email to Raaaaay     
Does the "seperate conductor" (a pink wire I assume) run from the tank level sensor to a terminal block at the stern of the boat, and then back up to the gauge at the center console, OR does this pink wire run directly to the gauge on the console?????

Obevioiusly, I have almost no small boat electrical wiring experience, and I will be hiring someone to do most of the eoectrical. I just want to buy the wire and run the wire for the fuel gauge before I seal down my tank panel cover.

L H G posted 05-02-2011 04:01 PM ET (US)     Profile for L H G    
If you enlarge this photo, starboard side of the transom, you can see how Boston Whaler did the fuel tank ground on the early 19's. The green ground wire looks to be about #12 gauge. current=Scan0006.jpg

Fuel gauge sender wiring is accesible in the access plate behind the console. Whaler ran continuous 2 stand wire, first under the floor cover to the back of the fuel tank, then in the tunnel up to the console. The gauge was rigged with an on-off pull switch. The entire top of the fuel sender and it's wire connections was packed in grease. The tank had a raised ring, about 1/2" high, to contain the grease.

When I re-wired my instruments, and installed a new fuel tank sender, I eliminated the on-off switch for the fuel gauge, so the fuel gauge reads constantly, just like in a car. I have the original Stewart Warner gauge, in like new condition, if you need one.

Raaaaay posted 05-02-2011 04:20 PM ET (US)     Profile for Raaaaay  Send Email to Raaaaay     
Larry, thanks for the offer of the fuel gauge, but I already picked up a set of Suzuki gauges for my new to me DF115 that I will be installing soon.

Larry, in pic 42 on your Outrage 19 you show your terminal block. What components fill up the 6 positions on this block?

L H G posted 05-02-2011 07:21 PM ET (US)     Profile for L H G    
Ray - I assume you mean this photo current=R1-6.jpg

The whole installation, under the starboard gunwale, is my design, includes at the far left, the main 40 amp circuit breaker.

The two left postions on the terminal block are the stern negative common grounds, something Whaler often used to eliminate having to run a bunch of separate ground wires up to the console. Instead, the main power cable ground serves all. The other four postions are the switched power (positive) leads to the bow light, stern light, bilge pump and under gunwale mounted courtesy lights. The return gounds from all four of those accessories are connected to the two left postions as mentioned. You can see the plug for the very tall original stern light pole in the photo.

Raaaaay posted 05-02-2011 08:27 PM ET (US)     Profile for Raaaaay  Send Email to Raaaaay     
Thanks for the details, I will be working on this and probably doing something similar
jimh posted 05-02-2011 08:59 PM ET (US)     Profile for jimh  Send Email to jimh     
The fuel tank level sensor is connected to the fuel tank level gauge by two conductors. One conductor carries the current from the battery positive, through the gauge meter movement, to the sensor. The sensor is typically a rheostat whose resistance varies in proportion to fuel level in the tank. In this way the sensor varies current flow through the fuel tank level gauge. The conductor carrying current from the gauge to the sensor is typically provided with insulation that is color coded to indicate the function.

From the article on wiring color codes in the REFERENCE section:

we see that the standard convention for the color of the insulation on this conductor is to PINK. If you do not have wire with PINK insulation--who does?--you can use wire with RED insulation with a WHITE stripe or just a wire with RED insulation to which you add a small wrap of WHITE tape.

The conductor that carries the return current from the fuel tank level sensor back to the gauge should have BLACK insulation, or perhaps BLACK with ORANGE stripe. Again, since wire with striped colors in the insulation is rare to find, just use wire with BLACK insulation and add a wrap of ORANGE tape or WHITE tape to help identify it.

The bonding wire is usually connected to a large flange or tab welded to the tank. It is typically not connected to the fuel tank level sensor.

The fuel tank level sensor is typically mounted onto the tank using a gasket. This tends to isolate the level sensor from the tank electrically, although the mounting screws will make electrical continuity. The return current should be taken from the sensor in the best manner possible to maintain as much isolation from the tank itself.

For me it is extremely difficult to describe electrical circuits in a narrative or to rely on photographs to show them. The fuel tank gauge and fuel tank level sensor should have included wiring diagrams. You should consult these diagrams for details. If you cannot read and interpret the diagrams, find someone local to you to help you.

jimh posted 05-03-2011 12:23 PM ET (US)     Profile for jimh  Send Email to jimh     
Current path for typical tank level gauge:

Battery Positive -->Gauge--->Sensor--->Battery Negative

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