Fuel gauge is bouncing

[sarmstrong]

1998 Chapparral 2130. While at WOT going across the lake the fuel gauge seems to bounce quite a bit as the boat bounces. I have owned several boats in the past and have noticed needle movements but none to this extreme- with 3/4of a tank it will bounce all the way down close to E. I have installed a new sending unit and ohmed out wiring while pulling/shaking wires and all seems fine. Any suggestions????

 

[tashasdaddy]

Re: Fuel gauge is bouncing

loose connection?

 

[SS MAYFLOAT]

Re: Fuel gauge is bouncing

Did the other boats that you owned have smaller tanks than the one you have now? It is possible that the larger tank will cause the gas to slosh around more than that of a smaller tank. This will cause a more erratic gauge fluctuation. Also the design of the tank will have an influence on needle fluctuation as well.

Other than that, make sure your ground is clean and tight to the tank and sending unit.

 

[a70eliminator]

Re: Fuel gauge is bouncing

Being you already replaced the sending unit there's not much i can think of other than a mis-match in resistsnce values between the gauge and sending unit, but as long as E is empty and F is full then all you can do is learn the amount of needle bounce to indicate fuel level until the needle falls off the pin, wait a minute maybe thats what's happening!

 

[Silvertip]

Re: Fuel gauge is bouncing

fuel gauge sending units have no "dampening" so they are free to dance up and down as the fuel sloshes in the tank. You have no choice but to live with what you have. At WOT you should not be focused on the fuel gauge anyway. Check fuel level when you leave the dock and when the boat is not bouncing. Your other option is to install a fuel flow monitor that provides the same fuel monitoring capability as most new cars.

 

[chiefalen]

Re: Fuel gauge is bouncing

Welcome aboard !

This might not be the reply you wanted but here goes.

Fuel gauges on boats are known not to be accurate.

When i first get a new to me boat. Heres what i do, i fill it up after i come off the water and note how long, how far, and how much fuel she took.

This goes on for a few weeks.

Then i just fill it up every time i come off the water anyway and not bother writing anything down.

Connection at the gauge good?? Ground good?? You solder the connections?

Maybe it's the gauge?? You try a different one?

 

[Mark42]

Re: Fuel gauge is bouncing

Look at replacing the sender with a WEMA brand sender. Most senders are a float on an arm, and like everyone said before, they bounce with the sloshing gas. A WEMA brand sender is a vertical tube design, and is much less affected by sloshing gas. I ordered my new gas tank with a WEMA sender, but as of yet, I have not installed the tank. But I specified the WEMA sender because of what I read about its "anti-slosh" properties. Its not perfect, but should be lots better than a float on an arm design.

 

[Mischief Managed]

Re: Fuel gauge is bouncing

I would think a capacitor accross the two terminals on the back of the fuel gauge would effectlively damp the motion without a lot of effort or cost. That said, I run a Lowrance LMF200 with a fuel flow sender and have removed my gas gauge, so this is not something I've tried. I HIGHLY recommend the LMF200, it has a very accurate gas gauge.

 

[dingbat]

Re: Fuel gauge is bouncing

Look at replacing the sender with a WEMA brand sender. Most senders are a float on an arm, and like everyone said before, they bounce with the sloshing gas. A WEMA brand sender is a vertical tube design, and is much less affected by sloshing gas. I ordered my new gas tank with a WEMA sender, but as of yet, I have not installed the tank. But I specified the WEMA sender because of what I read about its "anti-slosh" properties. Its not perfect, but should be lots better than a float on an arm design.

I have WEMA senders on both my tanks as well. Very little gauge bounce at all.

 

[BoatingCop]

Re: Fuel gauge is bouncing

I saw that the WEMA sender has 2 wires. I sone a ground that goes to the battery and the other goes to the gauge? Thanks. I think I may order one for my Taylor.

 

[Mark42]

Re: Fuel gauge is bouncing

I saw that the WEMA sender has 2 wires. I sone a ground that goes to the battery and the other goes to the gauge? Thanks. I think I may order one for my Taylor.

Yes, one is ground, the other goes to the gauge. Black is the sender that goes to the gauge, blue/pink is the ground. Thats what it says on the Wema website. I'm going to check the resistance with a multi meter before connecting just to be sure.

 

[BoatingCop]

Re: Fuel gauge is bouncing

Is the best way to go straight to the battery with the ground?

 

[Mark42]

Re: Fuel gauge is bouncing

Is the best way to go straight to the battery with the ground?

You don't have to run a dedicated wire to the ground post on the battery. Just connect to an existing ground wire. If you are replacing a sender, there should already be a ground, because even the regular senders need a ground to work properly. Most standard senders have a tab on them that the ground wire connects to.

BTW, I checked the wire colors on my WEMA sender. They are black and pink, so it does match the website wiring diagram. Black is sender, pink is ground.

I find this very confusing because my whole life, black has been ground in DC and low voltage circuits. Of course, house wiring is also backwards, black is + and white is -. Go figure.

 

[bondocanadian]

Re: Fuel gauge is bouncing

Had the same problem on my boat. I finally traced it back to the loose positive wire going to the gauge, Tighten the connection and problem solved. Hope that helps