Fuel sender only working when out of fuel tank

[LJButcher]

Here’s something that’s stumped everyone I know. I’ve got a maxum 1800mx. The fuel sender is faulty or something strange is going on. When in the fuel tank there’s no reading on the fuel gauge - there’s over half a tank of petrol in the fuel tank. However if I take the fuel sender out and manually lift the float. It works as it should - the fuel gauge goes up and down. I’ve tried it in a bucket of water as well- Works as it should however when it goes into the fuel tank it doesn’t work. There’s definitely enough fuel in the tank as there’s 50L in there from an 80L tank. The sender is the type where it’s a float moving up and down a shaft. If anyone has any idea what’s going on that would be appreciated. Thanks

 

[bluejasper2]

hi there, could be a broken or bad earth on tank, or somethink in the tank stopping the float moving, try a cable to earth the sender . hope this helps.

 

[dmayes]

Petrol or diesel is lighter than water, does the float float in petrol? it might float in water and sink in the fuel.

 

[lynallbel]

Have seen the floats go porous on truck derv tanks.

Cheap bodge has got to be buy a universal fuel sender, the old fashined arm type, remove the float bit off the arm and attach to your sliding float, though as the new float would be attached to one side only it may cause the sliding float to stick?
Old carb fuel level floats, any old bodge to see if it works, then try and fashion something longer term.

Iirc the float has a magnet built in, and as this slides up and down the shaft it triggers reed switches inside the tube.

 

[simonfraser]

check it moves in a bucket of diesel before you fit it again ?