Outboard motors have a predefined horsepower. Making these motors go faster can be accomplished with a few modifications and replacements parts. In some areas, however, having a motor overpowered from it's original output is illegal.
Change the propeller on the outboard. If you are looking to get the top speed out of your motor, select a propeller that has a higher pitch. This will slow the acceleration of the motor but the overall top speed will increase. If you are looking for faster acceleration, decrease the pitch. The boat will reach it's max speed faster with a lower pitch but it will not go quite as fast.
Adjust the trim/tilt of the motor. Adjusting the tilt will change how the boat will move through the water. Lowering the trim will cause the front of the boat to raise. Raising the trim will keep the front of the boat lower to the water. Experiment with different tilting to find the sweet spot for the boat and motor combo.
Decarbonize the engine. Start the motor and run until it reaches it's normal running temperature. Spray an internal engine cleaner directly into the throat of the carburetor. Continue spraying it into the carburetor until the engine dies. Let the motor sit for a half hour. Start the engine. Decarbonizing the engine will remove any carbon that may have been affecting performance.
Carry out any required maintenance. Required maintenance includes changing the oil if it is dirty. Check the pump and it's impellers. If the impellers look worn, replace the pump. Always drain gas lines when the motor will not be in use for a lengthy period.
Check with the manufacturer if there are additional parts that may be added to increase the horsepower of the motor. Some motors can be upgraded a few horsepower by changing out the carburetor.
Items you will need
- Internal engine cleaner
- You may add other external parts to increase performance. However, this is not recommended as it may be dangerous.
- It may be cheaper to sell the current motor and purchase one that provides the horsepower you want.
- Remember which pieces have been changed out on your motor and keep them. If you plan to sell the motor, replace the standard parts before selling. It can create friction if the buyer finds out later that the motor he purchased has been modified.
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