How to Disconnect an Oil Pump on a Mercury Outboard

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The hose fittings on a Mercury outboard motor oil pump are barbed, push-on/pull-off fittings. The oil inlet line, which feeds oil to the pump from the oil tank, is gravity-fed. As soon as you disconnect the line, it will try to empty the oil tank above it. Regardless of the reason for disconnecting the oil pump from your Mercury outboard motor, the pump must be reconnected and the oil tank refilled before you use the motor again.

Items you will need

  • Pre-wired paper tags

  • Oil storage container

  • Duct tape

Locate the oil inlet line leading from the oil tank to the oil pump. Tag the line with a pre-wired paper tag.

Manually pull the oil inlet line from the pump and cap it with your thumb. Move a container suitable for oil storage under the line and drain the oil tank into the container. Cap the line with duct tape.

Tag the oil outlet line that runs from the pump to the fuel system with a pre-wired paper tag. Manually pull the line from the oil pump. Cap the line with duct tape to prevent system contamination.


  • "Mercury Marine Outboard Repair Manual 65-300 HP 1992-2001"; Seloc Marine; 2007

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.