How to Replace a Boat Fuel Tank Sending Unit
When the fuel gauge in a boat stops working, one might figure it's a gauge malfunction. After running down the connections from the tank to the gauge, and checking the gauge with an outside power source to make sure it's working (it is), there's only one thing left to do: replace the sending unit on the fuel tank. With a few tools, and a little time and patience, a new sending unit means that a working fuel gauge will once again grace the dashboard of the boat.
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Things You'll Need
- Combination wrenches Screwdriver Rags Acetone Torque wrench Putty knife Oil-absorbent pads
Instructions
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1
Use the screwdriver to remove the deck plate over the fuel tank.
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2
Drain the fuel tank into an approved container. Place oil-absorbent pads around and under the container to contain any fuel spills.
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3
Remove the bolts from the flange of the sending unit and remove the sending unit from the tank. Inspect the fuel lines from the tank and, if necessary, replace with Coast Guard-approved fuel lines.
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4
Use a universal-style sending unit for a replacement and check if the new sender fits. If the channel and float arm are to large for the tank, the channel may need to be trimmed. Another necessary adjustment may include bending the float arm to avoid baffles within the tank, or the tank walls. Bending the float arm within its original horizontal plane will have no effect on the accuracy of the gauge.
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5
Insert a clean rag into the opening for the sender. The cloth keeps old gasket material out of the tank. Scrape off the gasket material from around the opening with the putty knife, then wipe the rim of the opening with acetone to remove any remaining material. Remove the cloth from the opening.
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6
Press the new gasket onto the bottom of the new sending unit, insuring that it makes firm contact with the flange around the bottom of the unit. Insert the sending unit float-first into the opening. Dab a gasoline-proof screw adhesive onto the threads of the sending unit bolts and insert them into the hole, tightening them to the torque recommended by the sending unit manufacturer.
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7
Connect the wire from the fuel gauge to the post on the sending unit that is marked with the letter S. Connect the other post on the sending unit, which is marked with a "minus" sign, to the boat's common ground.
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Tips & Warnings
A primer pump can be used to remove the gas from the fuel tank.
Working with gasoline is dangerous. Flames, sparks or smoking in the area are absolute no-nos. A well-ventilated area is a must.
