Sooner or later, you'll have to remove and replace the propeller on your Yamaha outboard motor. It could be that you struck a rock or a submerged log and bent a metal propeller, or cracked the blades on a plastic or composite propeller. Or perhaps you've found that the propeller on your engine simply isn't efficient. Regardless of the reason, and regardless of your mechanical skill, you can install the propeller on your outboard motor yourself because it's no more complicated than slipping a ring onto your finger or screwing a nut onto a bolt.
Items you will need
Clean shop towel
Heavy marine grease
Yamaha engine operator's manual
Torque wrench
Pliers
Step 1
Disconnect the spark plug wires from the spark plugs to avoid an inadvertent motor start. Propeller injuries can be severe, and even fatal: don't take a chance with this.
Step 2
Put the thrust washer that you removed from the propeller shaft back onto the shaft in the same way and orientation as it was when you took it off. The thrust washer's tapered side will match exactly with the taper on the propeller shaft if you've done this correctly.
Step 3
Use a clean shop towel to apply a moderate coating of heavy marine grease to the propeller shaft. After you grease the shaft, slip the propeller assembly onto the shaft. Push the assembly as far up the shaft as possible.
Step 4
Twist the shaft nut onto the propeller shaft and tighten it finger-tight. The specifications in your operator's manual will provide the correct torque for the shaft nut; use a torque wrench to tighten the shaft nut to the proper torque.
Step 5
Insert the cotter pin in the hole that runs through the shaft nut and the shaft. Use the pliers to bend the ends of the cotter pin in opposite directions, one to the left, one to the right, to provide extra security for your propeller.