Dead fuel gages

[Captdoug]

How hard is it to change the fuel gauge sending unit? My 2006 42SS fuel gages read total full with the key on n totally empty when the key is off. I drove it for six hours and they never moved off full.

[tomschauer]

How many tanks do you have? I'm sure at least two. Its possible, but unlikely two senders failed at the same time. Is it possible you are running off an auxiliary tank?

[Captdoug]

I just bought the boat so don’t know how long the gauges haven’t been working. The boat has two tanks. I looked at the sending unit and there’s not much room between the top of the tank and the floor above it. Will the sending unit float be able to pivot around enough to remove it? Hopefully I don’t have to drain the tank and remove it to get the sender out.

[RGrew176]

A few years ago one of my fuel gauges quit working. First thing I did was to pull the wire clean off the contact points of the wire and the tank and the gauge was working again. In my case it must have lost a good solid contact from corrosion.

[Midnightsun]

Agree with Rick, 2 gauges at the same time is unlikely, sounds like a grounding issue. I would start with the wire connection at the tank.

[Captdoug]

Thanks sounds like a good place to start.

[Viper]

Do the needles move past the full mark when you key on as though the needles are pegging? If so, that's an indication of the sender wire shorting to ground or the tanks really are full. Turning the key off would cause the needle to return to empty as you describe. The short can be anywhere including the sender but as mentioned above check the connections at the tanks and the gauges. Make sure the connections are clean and tight, and ensure the sender and positive wires are isolated from ground. Also check the wire insulation around any wire that might being in contact with a grounded item like the fuel tank.

[Steve2020]

They just replaced a sending in our main tank on out 41CMY the only way it could be done was to gently pull up the carpet and make an access through the floor over the unit. One of the auxiliary tanks was acting up also that one luckily just needed the connection cleaned at the unit.

[jspin101]

Steve2020,
I have the same issue with my 41 CMY on the starboard side.
How big was the hole they made? What did the cover it with after?

[Viper]

If room allows, I usually use a 6" hole saw. This gives you plenty of room to work with and allows for a bit of deviation above the sender in case you don't quite get the center right over the spot you need to get to. Measure carefully before you cut so you only make one hole. You keep the piece that was cut out, fasten a 3/4" wooden backer under the hole, then screw the piece you cut out to the backer. Counter sink the screw holes and you flat head screws so they don't protrude above the surface of the floor. There will be a gap resulting from the saw teeth which you can caulk, then put the carpet back.