Fuel gauge is reversed

fln

Cadet
Joined
Apr 19, 2007
Messages
6
New to this board and have never posted before. Have a 90 hp 1999 Honda 4-stroke used and just mounted, gas gauge shows empty when full and goes toward full as you burn gas. Pulled sender wire (pink) off and turned on key, gauge went to full. Any help would be greatly appreciated.
Guess they are right when thy say a Honda is easy on gas, mine makes gas!
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Re: Fuel gauge is reversed

swap the wires on the gauge
That won't work. The sender is just a variable resistor. The wiper is one connection and the other connection is one end of the wired core. Reversing them won't accomplish what you need. A different sender that matches what your guage expects will.
 

Boatin Bob

Lieutenant Commander
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Sep 24, 2001
Messages
1,858
Re: Fuel gauge is reversed

Normally on a fuel gauge to test it you pull the sender (pink) off the and turn the key on or jumper 12v to the gauge. With no sender wire on the gauge should read empty. Then using a ground wire jumpered over to the S terminal and turn it on again it should full. Sounds like your symptoms are reversed?
 

fln

Cadet
Joined
Apr 19, 2007
Messages
6
Re: Fuel gauge is reversed

Thanks to all that replied. All gauges are marked on front as Honda. Is there a different type sender unit and gauge for each type of motors and hr power? Did not have this problem until 2000 Jonhson 2-stroke 90 went bye-bye.

Boat is Lund 2002 Prosport 1675. Bought new show room floor. Gas tank is under floor is 24 gal. Just seems like simple problem, gauge works only in reverse?? Adds gas on gauge as we use it.

Thanks to all.

fln
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Fuel gauge is reversed

Fuel gauges have absolutely nothing to do with the engine. The sender is in the fuel tank. It has a resistance range of 0 to about 240 ohms. The gauge must match the sender so that means 99% of the gauges are generic. If you have a reverse reading gauge, that says the sender is working. What you have reversed is the +12 and Gnd wires on the gauge. You are essentially measuring a voltage just as you would with a hand held voltmeter. If you reverse the leads on a voltmeter it will tend to read backward. If its a digital voltmeter it will indeed read the voltage but it will have a (-) sign in front of the number.
 

bruceb58

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Mar 5, 2006
Messages
30,454
Re: Fuel gauge is reversed

I would think that guage wouldn't work at all if the power was the wrong polarity. More than likely there is a voltage regulator in the guage that prodeces a reference voltage so that the guage reads the same independent of voltage(ie engine running or not). It puts this voltage across a resistor in the guage and then measures the voltage drop across the sender.

Did you have a gauge on this boat before and was it working properly? Why did you change the gauge in the first place?

If you take the pink wire off the sender and ground it, does it read full?
 

Boatin Bob

Lieutenant Commander
Joined
Sep 24, 2001
Messages
1,858
Re: Fuel gauge is reversed

Bruce...if you read his very first post he said " Pulled sender wire (pink) off and turned on key, gauge went to full." Which is why I stated that's not normal for a gauge to do, at that point the sender is not even in the picture.
 

fln

Cadet
Joined
Apr 19, 2007
Messages
6
Re: Fuel gauge is reversed

Ok here is what I have tried thanks to all that have offered.

1 pulled pink sender wire turned key on gauge went to full
2 reversed grd and +12v wires turned key on gauge went to empty (sender wire on)
3 pulled sender and measured wire to grd on guage about 120 ohms (1/2 tank) which is correct
4 pulled sender wire off shorted ground on guage to sender lug on guage went to empty. Guess I might try a new guage. Does it have to be a Honda guage?
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,454
Re: Fuel gauge is reversed

Bob,

You are right...at the last second I added that last line without rechecking his initial post.

Bruce
 

bjcsc

Lieutenant Commander
Joined
Jun 1, 2006
Messages
1,805
Re: Fuel gauge is reversed

Some gauges are sensitive and will be destroyed if grounded...try to find a test procedure for the gauge online...
 

Silvertip

Supreme Mariner
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Sep 22, 2003
Messages
28,758
Re: Fuel gauge is reversed

It does not have to be a Honda gauge. There is no physical connection to the Honda engine.
 

burroak

Senior Chief Petty Officer
Joined
Mar 29, 2007
Messages
651
Re: Fuel gauge is reversed

If I may, I'll give you the po' boy's fix. Magic marker, change the F>E; E>F. :D
 

fln

Cadet
Joined
Apr 19, 2007
Messages
6
Re: Fuel gauge is reversed

Thanks again for all the thoughts, think I'll do as burroak suggested What would look better pink or blue!!!

Keeper full..
 

Rclark2

Recruit
Joined
Jun 15, 2009
Messages
2
Re: Fuel gauge is reversed

Not sure if you fixed your problem or not, but I just fixed mine. Turns out the float on the sender was installed in reverse. I pulled the sender and flipped the float sensor over and she works like a champ. It was the last thing I could think of to do. I did all the same things you did with the wires and nothing worked. However, flipping the float over did work. Good luck.
 

Fl_Richard

Lieutenant
Joined
Jan 21, 2005
Messages
1,428
Re: Fuel gauge is reversed

Good call. Did you remove the sender and re-install it upside down or did it flip on it's own?
 

Rclark2

Recruit
Joined
Jun 15, 2009
Messages
2
Re: Fuel gauge is reversed

I had to remove the sender assembly from the tank, remove the 2 screws that held the float arm in place on the assembly, flip the float and re-attach. Pretty simple once I figured it out. The wiring was hooked up correctly. I have to say, it was very frustrating figuring this out, and no one I spoke to even mentioned that this could be the problem. Hopefully, this will help some other boaters out there.
 
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