Gas Gage Question

WHY does my Gas Gage bounce!!!??? It`s an older boat (Ranger 361V) and it only happens when i`m on plane Has anyone else ever experienced this on their boat before?

mine would kind of tick back and forth while running . Turned out to be bad sender

Mine has two tanks could both senders be bad?

Fishbonz it was my was my tachometer that was bouncing on me not the fuel gauge but I had a loose wire.. it was on the back of the tach. I tightened the nut and it quit. Just thought I would mention it. I agree with two sending units both to fail is not likely.,

Thanks Coolarrow! I`ll give that a look see.

Its a Ranger 300 series thing. Some did, some did not. The design of the original sender let it flop around. Ran several of them on memo bills from Ranger, every one did it to some extent. Tanks had little or no baffles also. First Ranger they sent me that did not was a 481

I bought a 2014 Ranger RT188. The gage would only go to half full when the tank was full,...so got a new one.
Second one would show 3/4 full when full, so got another one. Third one would stick at full and not move, so I
got a new one. Fourth and final one shows 3/4 full when full, and never goes below a half empty.
Good news is my Merc 115 sips gas, and I can see how much gas is in the tank when I open the battery access
door....way to go Ranger...

simple adjustment, fill tank, pull sender, gently bend arm up till it shows full and reinstall.

assuming it is not the type that goes vertically on a shaft, no idea how to adjust those.

The gas "gauge" (not gage) is a simple voltmeter. It measure the voltage from an electromechanical sender on/in the fuel tank. That stuff in the tank is liquid. There is a stiff wire arm that extends into the tank with a float on the end that floats in the liquid. As the floating float moves the wire arm up or down, the voltage from the "fuel sender" changes due to a voltage divider built into the assembly. So, when you make the contents of the tank slosh around, the float will move up/down abruptly enough to change the reading detected by the gauge. Nothing is "broken" - this is just the nature of a rudimentary fuel gauge system. There are more accurate fuel systems available - assuming you'd like to pay $300+ to get one.

The fuel in both tanks sloshes around - not just in one tank.

I've owned several brands of boats since the early 80s. I've never seen one with a poly tank that had baffles. All were open blow-mold containers that allowed fuel to slosh freely.

It's the sender that typically has the crude resolution of reading the tank level, not the gauge. As for blaming Ranger, they're just using standard components like virtually every boat company out there. The resistive wiper voltage divider is prone to tarnish/corrosion/wear, and that affects accuracy, along with the fact that the sender is a crude device, so rarely will two read the same, even on a known good gauge, or a calibrated voltmeter. There are some premier senders available for about $300 if you feel that adjusting the float of a $30 sender isn't accurate enough for you.

You should read up on marine fuel measurement systems and how they work. It's far less common to have gauge issues than sender issues. The gauge is a precision instrument in comparison to the sender. I'm not clear if you were replacing the gauge or the sender/float assembly.

your sender is a rheostat, think light dimmer.

it uses resistance on the ground circuit to signal the gauge.

academy sells a good one that is really easy to adjust, just read the directions.

Thanks for your response CA I simply purchased a new Gage ,installed it , PROBLEM SOLVED!!