How to Replace a Boat Propeller
- 1). Shift the motor to neutral and remove the spark plug wires from the spark plugs to prevent an inadvertent start.
- 2). Use pliers to bend the locking tabs up, off of the main bolt, on a Mercury engine. For all other motors, use the pliers to compress and pull the Cotter pin that's placed through the main bolt.
- 3). Jam a block of wood between the motor's gear case and the propeller to prevent the propeller from turning, and then unscrew the propeller nut with a pipe wrench. Remove the propeller nut and stash it in your pocket. Remove the propeller by sliding it straight off the propeller shaft.
- 4). Slide the new propeller onto the propeller shaft. The new propeller should be the same pitch and diameter as the old one, unless you have purposely chosen otherwise.
- 5). Lubricate the propeller shaft with the grade of marine grease specified by the motor's manufacturer. Replace the main nut on the shaft and use a torque wrench to tighten it to the torque specified in the motor operator's manual.
- 6). Bend the locking tabs over the top of the nut if your motor is a Mercury or, if not, push a new Cotter pin through the holes in the nut and spread the ends of the pin.
