I recently bought a second hand 50cc moped, and the fuel gauge always reads empty. I assumed that it was the float sensor that was at fault, so I bought a new one. I connected the new sensor but the gauge still isn't working. Does anyone have any suggestions?

  • Welcome to Motor Vehicle Maintenance & Repair! Commented Jul 28, 2018 at 0:45

1 Answer 1


Step 1: check the gauge works - usually grounding the wire to the tank unit cause a full-scale reading, if good proceed to step 2, if not check wire from gauge, gauge and supply.

Step 2: connect tank sensor to wire from gauge and earth/ground the sensor - move the float and observe gauge, if not working then likely a faulty sensor.

Step 3: fit sensor into tank and check tank is earthed/grounded correctly - use an extra wire to go between tank and ground, if it works - correct the tank earth.

  • Wrong answer. The sender is not grounded. It is mounted in rubber, so it is insulated from ground.
    – user62966
    Commented Mar 27, 2021 at 19:26
  • @user62966 The OP didn't identify the make and model of moped. Without knowing this info, how do you know that the sender in the OP's moped is mounted in rubber and doesn't have a grounding wire? Commented Mar 27, 2021 at 22:06
  • @DavidSupportsMonica if you want you comment to go to user62966 then you need to add them to the comment.
    – Solar Mike
    Commented Mar 27, 2021 at 22:08

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