When you change the propeller on one of Volvo's Penta marine engines, the job requires few tools and little in the way of supplies. Whether it's part of routine maintenance, in preparation for the motor's "long winter's nap" or because you're on the water and the propeller has suffered damage from a striking an object, swapping propellers is a straightforward process of taking things off and putting them back on in the same order.
Turn the ignition on, but don't start the engine. Use the tilt and trim to tilt the engine up, then turn off the ignition switch and pocket the key. Shift the engine into neutral to keep the propeller shaft from turning.
Use pliers to remove the cottar pin from the keeper that holds the propeller nut in place. Use a 1 1/16-inch wrench to remove the propeller nut and slide the thrust washer and propeller from the shaft. Check the propeller to ensure that the thrust bushing has remained on the propeller shaft.
Clean the propeller shaft, removing shells, fishing line and other debris. Slather white marine grease on the propeller shaft and inside the propeller's hub. Slide the propeller onto the shaft, turning it as needed to align it with the propeller shaft splines.
Slide the thrust washer onto the shaft and over the splines on the shaft, until it makes firm contact with the propeller. Thread the propeller nut onto the shaft and tighten until it's seated against the face of the thrust washer.
Tighten the propeller nut to between 70 and 80 foot-pounds of torque, using a torque wrench. Install the keeper, turning it until the hole in the keeper is aligned with the cottar pin hole in the propeller shaft. Bend the ends of the cottar pin, shift the engine into "neutral" and give the propeller a spin -- it should turn freely. Insert the key into the ignition, turn the ignition on but don't start the engine and use the trim and tilt control to lower the engine to the vertical position.
If you don't have a torque wrench readily available -- if, for example you've spun a prop off while on the water and you're installing the replacement -- you should tighten the propeller nut as best you can, loosen it, tighten it again and then, with fingers only, turn it an extra one-half turn before installing the spare keeper and cottar pin.
Propeller-strike injuries either maim or kill: when changing the propeller on land, disconnect the battery in addition to pocketing the key.