Inaccurate fuel gauge

fireguyfire

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Joined
Jul 27, 2012
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16
Gentlemen; I have a 1995 campion outboard 17 footer and the fuel gauge has never been accurate since I have owned it. The gauge and the sending unit operate, but not right; when it's totally full the gauge reads 3/5 and I can go for ever when it reads empty. Does this sound like a faulty sending unit? Opinions on troubleshooting?
 

crb478

Lieutenant Junior Grade
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Dec 6, 2006
Messages
1,036
Touch the wires on the sending unit together and observe the fuel gauge with the switch turned on. If the fuel gauge now reads full the sending unit is not sending an accurate signal. If it still reads 3/5 it is bad. The sending unit may be the swing arm type and the arm could be bent out of position. If you determine it is bad you have the option of replacing the sending unit or trying to rebend the arm. If you choose to replace it I would consider one of the vertical float types. Simply get one about 1/2 inch shorter than your gas tank depth and install it. It will not cost you anything to rebend the arm though.
 

fireguyfire

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Joined
Jul 27, 2012
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16
Thanks for the tips; ill trouble shoot it and bend the float this afternoon. If I have to replace the sending unit, my issue is going to be that my tank is only 4 1/2 inches deep where the sending unit goes in. Anybody know if they make 4" vertical float units?
 

crb478

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Dec 6, 2006
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If it is only 4 1/2 inches you will probably have to use the swing arm type. Sounds like a stepped tank and the arm will need full travel to be accurate.
 

dingbat

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Nov 20, 2001
Messages
15,414
Thanks for the tips; ill trouble shoot it and bend the float this afternoon. If I have to replace the sending unit, my issue is going to be that my tank is only 4 1/2 inches deep where the sending unit goes in. Anybody know if they make 4" vertical float units?

Bag the float sensor....go to solid state. WEMA..available in 4"-60" in length
 

UncleWillie

Captain
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Oct 18, 2011
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3,995
Interesting. You use one of these?
And where does it say it's solid state?

They are "Solid State" in the eyes of the common user in the sense that there are no observable moving parts other than the floating magnet. The tube contains a series of resistors and magnetic reed switches.
They will usually report 8 total positions; Full, Empty and 6 steps in between.
The gauge will definitely jump between positions as the gas sloshes in the tank.

A boats fuel gauge is only good enough to remind you if you filled the tank before leaving and you are now almost bone dry.
Anything in between is mostly wishful thinking.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Yes, I went back to their website. It says it measures in 0.5" increments which should easily be fine for most applications. I actually need to replace my sender this winter in my pontoon boat. I might look into this.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,414
It says it measures in 0.5" increments which should easily be fine for most applications.
They are pretty darn accurate. I have both sensors (dual tanks) tied to my fuel management system for level feedback. Gauge level and consumption are always very close.

For what ever reason I get very little, if any fuel level "bounce". I don't know if they have some sort of damping in the circuitry by they bounce no more than any automobile gauge.
 
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