wiring for gas gauge

[quad59]

I have been going through my new to me boat and changing a bunch of wiring. I have everyhting working as advertised except the gas gauge which has never worked for me. I checked the sending unit full and I checked it empty and it seems to be working ( the fuller the less resistance?). My question is where do and what wires go on the gauge. I have one from the post of the sending unit and one from the tank case(ground), on the gauge I have four posts, two are for back lighting and the other two one says I and other says S. I assumed s meant sending unit. Does anybody know what goes where?

 

[gcboat]

Re: wiring for gas gauge

This might help - hopefully:
Here are the standard wire colors used in the boating industry since the late 70s. When re-powering a boat with a newer motor this is a handy reference. Most boats use these standards but always double check in case changes have been made!
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BIA Wire Color--------------------Where it is used
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Black---------------------------------All Grounds
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Black with Yellow stripe---------Magneto/short to Kill
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Gray----------------------------------Tachometer signal
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Yellow with Black stripe---------Choke
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Red----------------------------------Unprotected(12V+)from battery
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Red with Purple stripe-----------Protected(+12V)from battery
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Purple-----------------------------(+12V)from ignition switch
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Tan------------------------------Overheat sensor to warning horn
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Pink-------------------------------Sending unit to fuel guage
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Yellow with Red stripe----Ignition switch to starter solenoid
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Yellow-----------------------------charging stator to rectifier
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Lt.Blue with White stripe--------Trim up
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Green with White stripe-----------Trim down


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Some more standard wire colors used on many inboard boats, always double check though, as some vary or may have been changed along the way!
Some standard colors for boats since 1980 are as follows:
? heavy red 10 guage (main battery)
? heavy black (main ground)
? purple (ignition)
? yellow (starter solonoid)
? grey (tachometer)
? brown (temperature)
? blue (oil pressure)
? brown with stripe (alarm)
Accesories
? pink (fuel sending unit)
? yellow (blower)
? brown (bilge pump)
? grey (navigation lights)
? heavy green (bonding wire)
? red (misc electrical add-ons , vhf , depth finder, stereo, radar, power supplies)

 

[quad59]

Re: wiring for gas gauge

I have ran all new wires and the coloring issue is out the door. Most of what I am using is shielded wire with four or five groups in a strand. Lights and everyhting else is easy. I just need to know where to put them on the gauge...For example does the sendint unit wire go on S and the tank case go on I , I know I need to add an ignition powered power wire so where does that go on the sending unit Wire/post?? and do I need to add another ground or should the tank be straight grounded? I just need a diagram and I can figure it out and I have not yet been able to find one through search.

 

[Sid Schuster]

Re: wiring for gas gauge

Mine is wired with the sending unit going to "S" and ignition to "I" and the ground on the sending unit to a common ground, and the ground on the inlet on the bottom of tank spout to the fill nozel so it will be earth grounded when filling at a gas station. Hope that helps.

 

[Silvertip]

Re: wiring for gas gauge

This should have been posted in the "Electrical" section but we have an answer for you anyway. I've posted a wiring diagram for the fuel gauge about five times in the last week. The "search" function is a useful tool but it is no good if one doesn't use it. Here is the diagram one more time.

"S" on the sender goes to "S" on the gauge.
"I" on the gauge gets connected to "I" or +12 volt on any other gauge that is active when the key is on.
G on the gauge is ground and like "I" can be connected to the ground terminal on any other gauge or to the ground buss at the fuse panel (if there is one).
You do not need to run a ground wire from the shell of the sender all the way up front. Ground (negative post) on the battery is the same as ground anywhere else on the boat. Ground on the gauge is the same as ground on any other gauge.
The internal gauge lights get hooked to the same wires on any of the other gauges.