How to Replace a Boat Prop Seal

by Tami Parrington

A sure sign that your prop seal needs replacing shows up when you change your oil. In addition, trouble with the prop seal could be brewing if there is a small lubricant leak under your outdrive after the boat has been sitting for several days. The prop has a seal that prevents water from getting into the mechanics. If water has leaked into the oil, the oil will look milky when you change it. A simple inspection and changing the prop seal can save you thousands of dollars in outdrive replacement. You should be able to change a prop seal yourself without too much difficulty.

Place the 4-by-4 between the prop and the outdrive to keep the propeller from spinning. Use a prop nut wrench, or a 1-1/16 socket wrench to loosen the nut at the center of the prop. Remove the nut and set it aside. Use the tapered, blunt end of the prop nut wrench, or a flat-head screwdriver, to lift the tabs out of the lock washer beneath the nut. Remove the tab and the washer and set them aside.

Remove the prop from the drive shaft. If the prop is stuck from corrosion, use a hammer to knock it loose. Tap it gently to prevent damaging the prop.

Remove the thrust washer that sits behind the prop. Pay attention to the direction of the thrust washer so you can replace it in the proper direction.

Inspect the outer seal that sits behind the thrust washer. There will be grease present, but it should not be drive lubricant weight oil. If anything but the sticky, pasty prop grease is present, water could be leaking through the prop. Remove the seal. Place a new seal on the drive shaft with a prop seal driver to get the seal firmly under the carrier.

Reinstall the thrust washer and slide the prop back into place on top of it. Insert the washer and locking tab inside the prop. Press the tabs into the washer with the back end of the prop nut wrench or a screwdriver. Replace the prop nut and tighten firmly with the prop nut wrench or a socket wrench.

Items you will need

About the Author

Tami Parrington is the author of five novels along with being a successful SEO and content writer for the past three years. Parrington's journalism experience includes writing for eHow on medical, health and home-related topics as well as writing articles about the types of animals she has raised for years.

Photo Credits

  • photo_camera inflatible boat image by Wimbledon from