How to Remove an Inboard Prop (With or Without a Puller)

An inboard propeller sits on a tapered shaft, located by a key and held by a prop nut and a locking jam nut or a self-locking nut, usually with a cotter pin. Over time the bronze or nibral hub seizes onto the taper, so the right way to remove it is with a propeller puller that presses the hub off the shaft evenly. Hammering on the prop or prying against the strut can bend the shaft, damage the strut bearing and even harm the transmission, so a puller is worth using.

Before you start

• Make sure the engine cannot be started: remove the key and switch off the batteries.
• Support the boat securely if it is out of the water; most prop work is done on the hard.
• Wear gloves; prop blades can be sharp, and the prop is heavy.
• Have the correct puller for your shaft size, a large wrench or socket for the nuts, and a new cotter pin for reassembly.

How to remove an inboard propeller with a puller

1. Remove the cotter pin from the end of the shaft.
2. Loosen the outer jam nut and the prop nut, keeping the shaft from turning with a block of wood between a blade and the hull or a shaft holder.
3. Back the prop nut off a few turns but leave it on the shaft, so the prop cannot fly off when the taper releases.
4. Fit the puller as its instructions describe, behind the hub and against the shaft end.
5. Tighten the puller steadily until the hub breaks free of the taper. Follow the tool maker’s limits; do not overload it.
6. Remove the puller and the nut, then slide the prop off and keep the key safe.

How to remove an inboard prop without a puller

Owners sometimes try heat or striking the hub, but both risk damage: heat can affect the hub and nearby seals, and hammer blows travel into the shaft, coupling and strut bearing. If you do not have a puller, a boatyard or prop shop can remove the prop quickly with the right tool, which usually costs less than repairing a bent shaft.

Inspect while the prop is off

• Check the shaft taper and keyway for wear, cracks or twisting.
• Check the cutless bearing in the strut for play.
• Look for fishing line around the shaft and seal.
• Check the prop for bends and damage; see how to tell if a prop is bent.

Reinstalling the propeller

1. Clean the taper and the hub bore; they must be free of corrosion and burrs.
2. Fit the key and check that the prop seats fully on the taper without riding on the key.
3. Push the prop onto the taper, using a pusher if you have one, so it seats firmly.
4. Fit the prop nut and jam nut to the specified torque, then fit a new cotter pin.

Choosing a replacement inboard prop

Match diameter, pitch, rotation, bore and keyway to your shaft and engine. Start from the markings stamped on your current prop; see the propeller sizing guide, 3 vs 4 blade props and prop materials, including bronze and nibral.

Tools and props we list

• PropSmith 3.00 Prop Pusher Puller (for 3-inch shafts; other sizes need a different PropSmith model): $942.99
• 18 inch DynaQuad 4 blade bronze prop: $1,318.49
• 18 inch DQX 4 blade nibral prop: $2,100.49
• 17 inch Dyna-Jet 3 blade bronze prop: $1,060.49

Browse boat propellers.

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