Gas guage

[JPsanta]

hi , my gas guage was not working in the boat , pulled sending unit and replaced it, hooked it all back up , it reads the gas level now , but when you turn the key off , and shut the battery to off it still reads how much gas in the tank instead of going to zero , looking for help and TY

 

[Scott Danforth]

how did you power the gauge?

 

[Chris1956]

A lot of fuel gauges stop moving when power is removed. When they are powered they move to the correct fuel position. If the fuel tank is empty, they will move to zero when power is applied.

So, if you turn the ign key off, and she has 1/2 tank fuel, and you drain it, the gauge will not move from about the 1/2 position, until you turn the ign key on.

 

[kd4pbs]

Unplug the sending unit when you turn off the boat to ease your mind as to whether or not it is just the way the gauge works.

 

[JPsanta]

i thought it would be like a car fuel guage , went to turn the key off the needle drops to empty

 

[Chris1956]

Not so....

 

[StewartL]

That's normal for many boats. The gauge often stays on if it has a constant 12V power source from the battery. It will reset when you disconnect the battery or the power is drained. It's not a problem with your new sender.

 

[Scott Danforth]

gauges should not have constant power. they should be powered by the ignition circuit.

however some gauge air cores do not move to 0 (home) on their own. @JPsanta verify if you have 12 volts on the purple wire on the back of the gauges with the key off.

 

[Grub54891]

To ease your mind, put a meter on the tank feed wire and see if it has voltage, I bet not.

 

[JPsanta]

interesting , went and checked fuel gauge yesterday at supper time , gauge said tank was full , before when i start this post , i had just under half a tank

 

[Grub54891]

interesting , went and checked fuel gauge yesterday at supper time , gauge said tank was full , before when i start this post , i had just under half a tank

Do you know if the tank is actually full?

 

[JPsanta]

i would say slightly less than half , and no voltage at the gauge

 

[JPsanta]

this new sending unit is 33 - 240 ohms , i wounder if there is a compatibility problem with the gauge

 

[Chris1956]

Depending on fuel gauges to be accurate is tough. My speedboat has been thru 4 or so fuel tank gauges and the equiv fuel gauges changed over the last 45 years. It has a 8" tall tank. So, when the gauge reads empty, there is still 6 gallons left. !/4 tank is 9 gal, full tank is 18 gal. Each new gauge or sender has read the same.