Fuel Gauge Reading Backwards

[msautoso]

Have a new Honda/Faria Gas Gauage and the sending unit in my boat is a rochester. At present it reads backwards. float up moves towards empty / float down goes to fuel. I know the gauge is wired correctly. Can I swith the signal and 12v wire to make it read correctly. I have read that some sending units do not work with some gauges and that you can reverse the rheostat on the sending unit to make the gauge read correctly. However do not see how this can be done on my particular sending unit. Any Ideas would be greatly appreciated.

 

[Silvertip]

Re: Fuel Gauge Reading Backwards

The sender is a resistor, switchting it won't matter. You are correct that fuel gauges require a matching sender. It is highly unlikely the sender is wrong. It is highly likely the gauge is not a match for the sender or is simply for another installation. A remote possiblility is that the sender float arm is working backwards. On some senders it is possible to reverse the arm. In other words hold the sender with the arm pointing either to the right or left. With the sender held in that same position, remove the arm and assemble it so it points in the opposite direction. This is NOT the same as reversing the leads.

 

[msautoso]

Re: Fuel Gauge Reading Backwards

The sender is a resistor, switchting it won't matter. You are correct that fuel gauges require a matching sender. It is highly unlikely the sender is wrong. It is highly likely the gauge is not a match for the sender or is simply for another installation. A remote possiblility is that the sender float arm is working backwards. On some senders it is possible to reverse the arm. In other words hold the sender with the arm pointing either to the right or left. With the sender held in that same position, remove the arm and assemble it so it points in the opposite direction. This is NOT the same as reversing the leads.

"I pulled the sending unit and you can not reverse the arm on this particular unit. I went to a local marine store and purchased a universal sending unit and was able to reverese the arm/rehostat and it now works. How accurate not sure but works."

 

[Silvertip]

Re: Fuel Gauge Reading Backwards

Accuracy of fuel gauge on a boat is almost impossible to achieve because the attitude of the boat changes so much which alters the way the float arm sits. You can bend the float arm to make the gauge accurate at Full, 1/2 or Empty but you cannot make it accurate at all three. It makes no sense to make it accurate at full since you know when it is full. You want it accurate at empty. Set it so it reads empty when you have a couple of gallons (3-5) remaining. The number you select should be based on the size of the tank. If you have a 15 gallon tank it would make no sense to have it read empty with 5 gallons left. If you have a 30+ gallon tank it would.