Fuel Guage Accuracy

Patsy Mac

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I have a 98 268 Islander, and recently noticed that the fuel quantity reading is inaccurate. Although I have topped off the tank to almost overflowing, the guage reads about 1/2. It has one gas tank, and previosuly seemed to work fine. I cleaned the electrical connection at the tank sensor, no improvement. Are fule QTY issues common in GW's? Should I pull out the sensor from the tank next? Any help troubleshooting would be much appreciated.
 

megabytes

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You may indeed have a faulty sensor. I typically use the FMS to determine how muhc fuel I have but I always keep the boat full so it is ready to fish. Of course the gauge is a good sanity check in the event I forget to zero the FMS after fillup or it reads incorrectly.

You can email or call GW customer service for the part number and probably replace the sensor yourself.
 

seasick

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Note that if the tank is full or near full, don't pull the sender if it at the same end as the pickup. That end of the tank is probably full to the top and fuel will spill out into the bilge when you remove the mounting plate. How do I know this?? don't ask...
Eiter drain fuel out just run the fuel down.
 

TBone

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Both my tanks are reading incorrectly. The main use to work but since I

filled it up this year it worked for two trips and now it constantly reads Full

(I WISH!!! :shock: )

The Aux tank reads 2/3 full since I had it, full or empty, it only changed

a couple bars.

So like Mega I top off every trip out. My gauges are Yamaha.

Did yours do this, has anyone had this problem?

How much are the senders?
 

BobP

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I replaced both my senders with WEMA units. Google WEMA gauges.

Very well made, not like the flimsy originals with the hinge and open wires.

Get the sender length from Grady Customer service.

I think about 60 bucks each delivered.

If you order WEMAs, call on phone to place order.

You may have some touble getting the original screws out.
 

Hookup1

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Fuel Guages

I replaced both sending units on my 1997 Islander and everything is fine. Use the WEMA sensors-better built and probably the last time you will need to replace them.
 

jweschler

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I just bought two new senders from WEEMA for my 1995 232 Gulfstream for my main tank 92 gal and my 90 gal aux tank. Called Grady White and they told me that I had a 14 1/2 for my main 92 gal tank and and a 26 1/2 for my 90 gal aux tank. But when I called WEEMA they do not sell any half sizes over 18 1/2. So I bought a 14 1/2 for $45.50 and for the 26 for $52.00( I went with the smaller size which grady and WEEMA said to go with the smaller one to be safe). I should have them soon and will let you know if that fixes the reading errors I have been having for years. I have had to remove them and clean them and then they work for a while and then stop. Thanks.
 

BobP

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I can't believe the sender's length is that long on the Gulf.

Recheck those numbers and if not sure, measure the tank yourself, this is how you do it.

Remove the sender, measure to bottom of tank to top, then deduct 3/4 in. I believe to equal sender length.

Make sure you do it safely, don't make any sparks, and don't wear synthetic clothes, wrist watches, and keep anything out of shirt pocket or around your neck that can fall in.
 

DonLINY

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I have a 1989 Gulfstream and I called Grady last week and they told me the depth of the Aux tank was 15 1/2 inches. My aux tank holds about 55 gallons.
 

Boats Rock

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When you guys replaced your senders were your old ones made buy Isspro. They look like tubes. If so did you use your old screws over again
 

seasick

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According to WEMA, you should measure the depth from the top of the mounting flange to the bottom of the tank. Subtract 1 inch for plastic tanks and 3/4 inch for metal. Take that measurement and round to the nearest 1/2 inch. That is the length to order.

You need new gaskets or o-rings but would reuse the original screws.
 

jfmagana

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Pretty common problem...your fuel sending unit may be bad. Easy fix, but it will likely happen again. Maybe somebody has a suggestion on a better quality sending unit than the typical ones.