Boat Fuel Sending Units

Boat fuel sending units are by far the most popular on the market today, but a new reed style is growing in popularity. The swing arm style is less expensive and can be adjusted to fit most tanks. Moeller offers two size a 4 -12” model and for tanks up to 24”. These can be cut to fit for less than 12” or bolted together for over 12  inches to achieve the desired tank depth. The reed style sending unit must be installed at  the proper length for your desired tank depth. While this style is also a bit more expensive, it is more accurate when fuel sloshing occurs. The following information offers some guidance if you are having trouble with a swing arm style boat fuel sending unit. 

Fuel gauge not working? Is it the fuel tank sending unit or the gauge itself? Here is a simple trick to check to see where the problem is. 

• First locate the sending unit in the tank. You should see 2 wires one on the center stud (power wire +) and the other wire connected to a tab or under a screw holding down the sender (ground wire - ).
• Turn the ignition switch to the power on position (energizing the gauges not starting the engine).
• With the ignition switch on. Go back to the sending unit and with a screwdriver lay it across the center stud to the ground wire. This will complete the circuit and if the sending unit is bad, but the gauge and wiring are good, the gauge will read full. If the gauge needle doesn’t move, the gauge or wiring is bad. Replacing a bad fuel sender is easy.
• Disconnect the battery or turn off your battery switch if applicable. The sender is held in place by 5 machine screws.
• Remove the power and ground wire.
• Remove the five machine screws holding the sender in place. The bolt pattern is a marine standard so for replacement we just need to know the length of the sender.
• When removing the fuel sender and gasket take care to make sure which direction the arm swings.
• Check the length of the sender. Replacement senders are designed to be cut or bolted together to make the desired length.
• Reinstall your new sender with a gasket, again make sure the arm swings in the proper direction. Install your 5 screws torque tight, reconnect the wires, and reconnect the battery.
• Installation complete.