How to Increase the Power in an Outboard

Modifications can be made to increase the power of an outboard.

You can increase the power of an outboard motor by making modifications, such as installing a transom jack and changing the propeller type. A transom jack will extend the intake further back from the transom where it can get better water flow. A prop with a different pitch will affect the performance of the boat by increasing the RPMs. You can increase the power in an outboard by first determining what type of modification to make.

Things You'll Need

• Socket wrench
• Hammer
• Transom jack
• Prop puller

Instructions

Transom Jack

1. Loosen the bolts that are used to secure the motor to the transom with a socket wrench.

2. Support the motor then take out the bolts. Place a wrench onto a lock nut and the socket wrench onto a bolt. Turn the socket wrench counterclockwise to loosen the bolt. Repeat this step for the other bolts on the transom. Continue to loosen the bolts and then take them out.

3. Remove the motor and set it aside. Keep the motor supported upright until you are ready to reattach it to the boat.

4. Place the transom jack plate onto the transom of the boat. Insert the bolts for the jack plate into the bolt holes on the transom. Secure the bolts with the socket wrench.

5. Set the motor onto the jack plate. Insert the bolts into the motor mount and jack plate. Hand-tighten the lock nuts onto the bolts. Place the wrench onto the lock nuts and the socket wrench onto the bolts. Turn the wrench clockwise to tighten the bolts.

Change the Prop

1. Loosen the retaining nut used to secure the prop to the shaft of the outboard with the socket wrench. Turn the socket wrench counterclockwise to loosen the nut.

2. Place the propeller puller onto the prop then pull the prop to loosen it on the shaft.

3. Turn the retaining nut counterclockwise until it comes off. Take the old prop off then insert the new prop onto the shaft.

4. Hand-tighten the retaining nut then secure it tightly with the socket wrench.

Tips & Warnings

• Tap on the bolts with a hammer if they are stuck and will not come out.

• Be careful: the propeller blade may turn when trying to remove the nut, and a sharp propeller blade can easily cut your hands.

References

• Pennsylvania Fish and Boat Commission: Enhancing Outboard Jet Performance
• Marine Parts: Installing an Outboard to the Boat Transom
• Marine Accessories: How to Change a Propeller

Resources

• WMI: Installing a Jack Plate
• BoatFix: Propeller Selection