How to Remove & Install an Outboard Propeller

Whether you want to swap propellers, replace a damaged one, inspect the oil seal or remove debris, replacing an outboard propeller is pretty simple.

Outboard propeller replacement the basics

No special tools are needed to get the job done. Typical toolbox items such as a ratchet and sockets, screwdrivers and pliers will suffice. An outboard prop swap/reinstall can usually be done in a matter of minutes. Here’s how to remove and replace an outboard engine propeller.

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Removing an Outboard Propeller - The Basics

Bend back the tabs on the lock-washer securing the propeller nut, or remove the cotter pin securing the propeller castle nut. Next, remove the propeller nut or castle nut, and pull the propeller off the prop shaft.

PRO TIP: Place a block of wood between the propeller’s blades and the ventilation plate to keep the prop from turning.

Outboard motor propeller removal

Outboard motor prop removal

Outboard engine propeller removal

Outboard engine prop removal

Remove the thrust washer, then inspect it and replace it if it’s worn. You may have to pry the thrust washer slightly to break it free.

How to remove an outboard motor propeller

NOTE: In the image above, the outboard's lower unit has been removed to make other repairs. You don't need to remove the lower unit from the outboard to get the propeller off.

How to remove an outboard motor prop

With the prop and thrust washer removed, you can inspect the oil seal for wear and remove any debris such as old fishing line tangled around the prop shaft.

Installing an Outboard Propeller

Replacing the propeller is basically reinstalling the parts in reverse order, but you should first lubricate the prop shaft with PTFE marine grease. 

  • Reinstall the thrust washer, then install the new propeller or reinstall the one you have.
  • Reinstall the lock-washer and prop nut, or the castle nut, and torque the nut according to the manufacturer’s specifications. 
  • Bend the tabs on the lock-washer back over the propeller nut, or reinstall the cotter pin to secure the propeller castle nut.

New outboard propeller installation

If you’re looking to buy a new propeller but not sure what the correct size prop to get, watch the video above to learn how to find prop size dimensions