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How to Install a Fuel Pump in a Boat

by Will Charpentier

How you install a fuel pump in a boat depends on several things, including whether the fuel pump is an electric fuel pump or a vacuum pump. There are similarities in the installation of each as well as differences. The process of mounting and installing a fuel pump in a boat is so straightforward as to be pedestrian, but unless you follow the process in the correct order, you end up with a mess.

The Vacuum Pump

Apply thread locker to the treads of the pump mounting screws. Set the fuel pump gasket on the bottom of the pump and thread the mounting bolts through the pump's mounting bracket and the gasket.

Place the fuel pump on the engine block. Thread the mounting bolts into the bores and tighten to the torque recommended in the pump mounting instructions, using a torque wrench or driver.

Press the fuel line from the fuel tank onto the nipple on the pump's intake side and slide the hose clamp forward so that it holds the fuel line on the connector. Tighten the hose clamp with a standard slotted screwdriver.

Press the fuel line from the fuel tank onto the nipple on the pump's outflow side and slide the hose clamp forward so that it holds the fuel line on the connector. Tighten the hose clamp with a standard slotted screwdriver. Press the vacuum hose over the nipple on the center of the pump cover and secure with a hose clamp.

Pump the primer bulb until the bulb is firm to the touch and inspect the pump connections for leaks.

The Electric Fuel Pump

Apply thread locker to the mounting bolt threads. Place the pump gasket on the bottom of the pump and insert the mounting bolts through the base of the pump and the gasket.

Set the electric fuel pump in place on the engine block and thread the mounting bolts into the bores. Tighten the bolts to the torque recommended by the pump manufacturer, using a torque wrench or driver.

Press the fuel line from the water separating fuel filter onto the connector on the pump's "In" orifice and slide the hose clamp forward so that it holds the fuel line on the connector. Tighten the hose clamp with a standard slotted screwdriver.

Press the fuel line from the fuel cooler onto the connector on the pump's "Out" orifice and slide the hose clamp forward so that it holds the fuel line on the connector. Tighten the hose clamp with a standard slotted screwdriver.

Solder the fuel pump's red power wire to the vacant terminal on the fuel pump switch, using a soldering iron and rosin-core silver-bearing solder. Loosen one of the grounding bolts on the engine block, wrap the fuel pump's black wire around it, and tighten the bolt with an adjustable wrench. Turn the pump switch to its "On" position and inspect the connections and the pump body for leaks.

Items you will need

  • Thread locker
  • Torque wrench
  • Torque driver
  • Standard slotted screwdriver
  • Soldering iron
  • Rosin-core silver-bearing solder
  • Vinyl electrical insulation spray

Tip

  • Spray the electrical connections on the electric pump with a vinyl electrical insulation spray.

Warning

  • Disconnect the battery leads before doing anything else. Not only do the normal warnings about electrical shock apply, but whether the pump is a vacuum pump or an electric pump, stray electrical sparks and gasoline vapors do not mix well.

References

  • "Evinrude Repair Manual -- 2.5 to 250 HP Models, 2002-2007"; Seloc Marine; 2007
  • "Mercruser Service Manual Number 17, Marine Engines, GM V-8, 305 CID (5.0L) / 350 CID (5.7L), Book 1"; Mercury Marine; 1998

About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.