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Last week I had a 1/4 tank according to my fuel gauge. A local boatyard fixed my courtesy lights and I filled up the tank. Now my fuel gauge reads completely, totally empty. Boat yard of course is playing dumb.
How do I troubleshoot the problem with the gauge (sender, gauge, power supply or wiring)?
Also go to the SEARCH feature and type in the words "check fuel gauge troubleshoot", without the quotes of course, searching the Boaters Forum and you'll get lots more info.
__________________ [red]MISS TEAK[/red], 25' Parker mod-V Sport Cabin "Life's too short to own an ugly boat ..." www.classicparker.com
My experience is that fuel gauges on boats are unreliable and prone to breakdowns early and often. Those fuel flow guages are a better way to keep track of the fuel in tank.
Here's the deal; fuel guage wireing goes first, the guage itself goes second, and the senders almost never go bad.
There are two wires running from your fuel tank to your guage, at ther guage there are three wires, the original two that run from the tank (one of which is a ground) and then a third wire, which is a power supply.
If you open up your access port to the tank you will see the two wires going to the sender. One will connect to a little stud right in the middle of the sender. This one should have a pink wire on it. Check the connector on the end of the wire for a good contact (it will probably be crimped) and it will probably be corroded too. Cut back some wire and replace the connector after you clean up the terminal.
The second wire to the sender will be black and it will probably have a little quarter inch blade connectors (there will be a male side tab built into the sender and the female side will be on the wire). This one may be, and in fact will more than likely be, corroded beyond recognition. You know what to do.
At the guage there are three wires. The back of the guage will probably have letter markings next to each of its three studs. One will have an "S" next to it. The "S" stands for "Sender" and it will have the pink wire that goes to the cernter terminal of the sender unit connected to it. There will be a stud that has a "G" for Ground next to it, this one gets the black wire that you had to replace because of all the corrosion. The back of the guage will also have a stud with an "I" next to it. This one is where the power comes in. Connect it to the ignition key so that it gets power when the key is turned to the On positon.
As for expenses, wire is cheap, senders cost around $30 as I recall, and depending on what guage you use they can be quite resonable - I think I've been paying about $10 each for them (Surplus Unlimited).
For whatever its worth I have three gas guages and I end up having to fix them at about the rate of one per year. Wireing rarely lasts more than 2 or 3 years, guages seem to be good for about 4 years, I have only ever had to replace one sender in my life, and looking back on it now I'm not all that sure it was actually bad.
Thom
P.S.: Here is my guess - Your yard bumped into or pulled on the wires for your fuel guage when they were fixing the lights. It was their action that cause the guage to quit but it wasn't their fault that it happened, it was goig to happen anyway because of the corrosion (or on a long shot a bad crimp that pulled apart while they were in there messing with wires), they may have sped up the process by about a week but it was gong to fail anyway so don't be too hard on them. Oh, and they know this too, or else if they are so inexperineced that they do not know it you should find a new yard.
I have digital Yam gagues. Top off the tank and it reads 1/2 to 3/4. also fuel level goes down to 1/4 sudden. top off tank again and it takes maybe 5 gallons. What should I check?
Now it is really getting to be time for wild guesses. Not that I mind making wild guesses, its just that when I'm proven wrong it hurts so badly ....
My guess is that if its been doing this all along that maybe the sender that got tossed into the tank is wrong for it. I do not know much about these things but I do know that senders, even the adjustable ones, come in different lengths to accomodate tanks of different depths. Some senders have adjustable vertical arms that you preset after measuring the depth of your tank.
Also, I have a link at home for some super duper sending unit but at the moment I can not, for the life of me, remember what was so great about the thing. I sort of recall that it does not use a swing arm and that it is reported to give accurate readings from full to empty - something that most guages do not do. I will post again to this subject when I get home with a link that might help you out. By the way, the Yamaha guages do use the standard 35-240 ohm senders, don't they?
Only one I've ever had that worked is on my old Grady...
Troubleshoot? I think you oughtta shoot the trouble... The one on my Seapro didn't last through the 1st month, didn't even bother trying to repair.. As you've already read here, buy a Floscan or Navman, they both work.
Thom, are you thinking of the fuel sender from Centroid? It is a capcitance type sender with no moving parts. It uses a change in capacitance to drive the gauge. If and when I ever have a problem with my sender I will probably get one. If nothing else it is a new project to play with. I just bought a Cruzpro digital gauge that is calibrated to the tank. It is supposed to be super accurate. Haven't installed it yet.
My fuel guage went bad too, about one month ago. I did just as thom said, and that fixed it. I cut off and replaced the connections for both wires at the tank, and one at the guage and all works fine (for now).
Thanks Thom....Great info.* It is sure better than what my mechanic told me.* He said, "These things are always breaking.* I can fix them twice a season or you can learn to live with the problem."* And this is from a Company that has never turned down a way to charge me...
Bottom line is that I don't have Thom's mechanical aptitude and don't want to be paying for these things twice a season* So I keep a log in my head and keep the tank pretty much full.* At 183 gallons it would take a very long time to burn a full tank...like 400 miles or 18 hours.
Parapram, maybe it is your mechanic. My experience with fuel guages has been quite good actually. That is, they work well and work for a long time if installed correctly and protected against corrosion. The only real problem is with their accuracy when the boat is bobbing around and the tank is less than full, but I can live with that.
You might be right.* BTW, I have changed boats and mechanics.* The one I quoted was my old mechanic.* Though my new boat has a similar problem as my*old one.... I never understood why this was so hard in a marine world (I've had problems on three different boats now) and I've never had a problem with a fuel gauge*in a Car...*
In any case, it is probably good practice to keep a mental log of your fuel consumption.* It can alert you to potential problems.* FloScan is great, but I am too cheap to buy one.
Fuel Gauge Not Working 
