Gone Outdoors

How to Add Tilt Oil in a Mercury Outboard

by Will Charpentier

Maintaining your Mercury outboard's hydraulic tilt system will ensure that your system works as well and as long as your engine, and perhaps longer. One major factor in the wear of hydraulic systems, like your tilt system, is operating without the correct amount of oil, or the wrong kind of oil. Be sure to follow the recommendations in your tilt system's operating manual for recommendations on the type and weight of oil to be used and check the level regularly as part of your regular maintenance schedule.

Raise your motor using your tilt control.

Find your trim pump. The easiest way to do this is by following the oil line from the tilt system, back toward your tilt control, or from your tilt control. While the pump is located in different places on different boats, with a Mercury outboard, it's usually tucked under some deck access plat in the rear of the boat.

Unscrew the recessed screw cap, usually on the front right corner of the pump. This is the oil filler cap. Remove the cap completely.

Check the oil level in the pump. The oil should come up to the second thread on the filler spout. Use your oil can with a flexible hose to fill the oil up to that level.

Raise and lower the motor about six times to bleed air out of the system. Screw the oil pump filler cap back on.

Items you will need
  • Recommended oil
  • Oil can with a flexible spout

Tip

  • If you continue to have problems with your tilt system, these problems will likely involve the hydraulic rams in the system. Frequently, these are not user-serviceable.

Warning

  • This project involves moving heavy weights in an uncertain environment. Appropriate caution is advised.

References

  • Outboard Engines: Maintenance, Troubleshooting, and Repair; Edwin Sherman; McGraw Hill Professional, 2008; p. 91 ff

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.