Found on the small-horsepower two- and four-stroke Johnson outboard motors, those under eight horsepower, the shear pin prevents the propeller from moving on the motor's propeller-shaft, serving the same purpose as the splines on the propeller-shaft and inside the propeller-hub on larger motors. A damaged shear pin will allow your motor to "over rev," risking damage to the motor. Shear pin replacement does not require you to remove the propeller, nor to replace it.
Cut the ends off the cotter pin. Free the remains of the cotter pin by grabbing the head with a pair of needle-nose pliers. On all models, except the 2- to 3.5-HP motors, pull the propeller cap from the propeller shaft.
Pull the shear pin from the propeller shaft using needle-nose pliers. Push the new shear pin into the propeller shaft in front of the thrust washer with the pliers.
Slide the propeller cap onto the propeller shaft and push a new cotter pin through the cap. Bend the ends of the cotter pin around the cap.
- Remove the nuts and cables from the battery posts before beginning.
- On the 2- to 3.5-HP motors, the propeller cap is part of the propeller. Simply remove the shear pin with needle-nose pliers and insert a new shear pin.
- "Johnson Repair Manual -- 2 to 8 HP 2-Stroke Motors and 5 to 6 HP 4-Stroke Motors, 2001-2009"; SELOC; 2009