5 Affordable Outboard Motor Tips to Improve Performance

An outboard motor can be highly effective at powering your boat— you just need to set it up correctly and take care of it well. It’s important to consider things like:

• Proper RPM range
• Boat propeller selection
• Adhering to manufacturer-recommended maintenance schedules

While getting an enhancement like a jack plate will improve your boat’s performance, it can be pricey. Hydraulic jack plates, for example, can cost anywhere from $500 to $1,500. Fortunately, there are some less expensive ways to help your boat’s engine operate at its best. Here are some affordable outboard motor tips to improve performance.

How Can I Improve My Outboard Motor Performance?

Prop Your Boat Correctly

A boat that’s over-propped can cause your outboard’s highest RPM to be lower than the wide-open-throttle RPM recommended by the manufacturer. This happens because the higher pitch causes more resistance to the water, keeping your propeller from revolving as freely as it can. The wide-open-throttle RPM is usually between 5,000 and 6,000 RPM, but refer to your owner's manual to be sure.

Running your RPM below the recommended range will make the engine work harder. This increased workload causes your combustion temperature to rise and will stress your boat’s internal parts.

An under-propped boat can also be harmful. If the engine spins above the recommended RPM, it'll wear down the parts, and your engine won't last as long. You can adjust your engine's wide-open-throttle RPM range by changing the propeller pitch. Increase the propeller pitch to lower the wide-open RPM or decrease the pitch to raise the wide-open RPM.

It’s also helpful to experiment with different propellers. Find propellers within your budget until you reach the performance you’re striving for.

One way to know if your boat is reaching the recommended RPM is doing a wide-open-throttle test using a tachometer, and your boat may be already equipped with one.

Performing a Wide-Open Throttle Test

1. Use the boat as you usually would, including the amount of equipment and number of passengers you typically have onboard.
2. Make sure the gas tank is about two-thirds full. Run the boat during calm waters and when there are few other boats to avoid affecting the results.
3. Switch to full throttle and have the motor trimmed out until you’re at top speed.
4. Record the RPM and then bring the boat to a stop.
5. Repeat the test going in the other direction to account for tides or wind and average the two RPM readings.

If the RPM average isn't in the middle of your WOT rating, that might mean you need to replace the propeller with one that has a more suitable pitch.

Trim Your Boat for Maximum Performance

Boats handle best when they run parallel with their at-rest waterline — you'll notice a more comfortable ride, increased speed, and more efficient gas mileage. The bow of your boat meets the water at a specific angle — and that angle has a direct correlation to how efficiently you operate your vessel.

For peak performance, set up your boat to use less positive trim. Be sure to point the nose of your outboard lower unit straight forward. That causes the thrust from the propellers to go straight aft. If you’re unfamiliar with the term aft, it’s a naval term that means “towards the stern (rear) of the ship.”

Outboards or lower units trimmed out have the noses point down, and the thrust is directed up. That means the thrust isn’t aft, reducing efficiency and increasing fuel consumption.

Minimize Your Boat’s Rooster Tail

Rooster tails are created when the boat’s propellers are tilted back in a way that causes water to shoot into the air. A fountain-like stream is formed right behind the boat as it moves through the water. Efficiently running boats tend to have rooster tails that lower as the boat accelerates. High rooster tails are usually the result of over-trimming and generally cause the boat to lose speed.

Certain propeller brands may also cause higher rooster tails than others. Consider the weight distribution that’s on your boat and the engine height as well. Make different adjustments, and if you see the rooster tail getting lower with each boat ride, you’ll know you’re going in the right direction.

Practice Good Filter Maintenance

Fuel filters are designed to prevent water and other contaminants from getting into your fuel system. Outboard engines need to have fuel that's water-free to perform well. Your manufacturer will usually provide you with guidelines on how often you should do filter replacement.

A good rule of thumb is to replace your fuel filters semi-annually, but they may need to be changed more often depending on factors such as vacuum gauge readings and fuel color.

If you see your fuel is a muddy brown color, that’s a sign that contaminants are getting into your fuel system, and the filter needs to be replaced.

When doing vacuum gauge readings, there are three color-coded zones. Green is the good zone, yellow is the marginal zone, and red is the bad zone. A fuel filter replacement should be considered if the gauge needle is pointing in the yellow or red zones. You'll likely notice an improvement in performance after you've changed out your fuel filter.

Consult Other Boaters Running Your Same Engine Model

It doesn’t cost you anything to ask for advice from other boaters who have your engine. Find a community of boaters in your town or online to get tips for high motor performance. Your boat manufacturer also may have a lot of helpful information to increase your boat’s performance. It’s always important to read through all the pages of your owner’s manual. It could potentially save you time and spare you a lot of frustration whenever your boat isn’t operating the way you desire.

Outboard Motor Performance FAQs

How Can I Make My Boat Motor Faster?

An easy way to help your boat motor go a little faster is by decreasing the weight on your boat. Clear out your storage compartment of everything except the essentials. When your boat is lighter, it has quicker acceleration, and the drag is reduced since the hull is riding higher in the water. Heavier items should be placed in aft storage compartments to avoid weighing down the bow. Drain the holding tanks and fresh water and take your boat out with less than a full tank of fuel to achieve greater speed.

Will Raising the Outboard Increase RPM?

Raising your outboard can help increase your RPM as a result of reduced drag. However, raising the outboard too high can cause the propellers to ventilate and slip-on acceleration.

Will a 4-Blade Prop Make my Boat Faster?

4-blade propellers are best for getting maximum thrust out of your boat’s engine and smoother cruising operation. It’s not uncommon for a 4-blade prop to cause your boat to lose a little speed compared to using a 3-blade propeller.

Bonus Tips

• Ethanol tends to attract water, which negatively affects your outboard motor’s performance. Use an effective fuel stabilizer to keep the ethanol in your fuel from over-saturating. Stabilizers have enhancers that improve your fuel combustion, which improves your boat’s performance.
• Repair bent or corroded propellers to improve the efficiency of your motor. While inevitably you’ll have to replace your propeller someday, see if it might be cheaper to have it refurbished.
• Make sure you change the lower-unit oil at least once a year. Fresh oil makes your engine run more efficiently.

Increasing the performance of your outboard motor can be done without expensive investments. The key is to continually adjust your equipment to find what works best for your particular boat. Proper maintenance is also vital to make sure you're not negatively impacting your motor’s performance.

Keep these outboard motor repair and maintenance tips in mind as you work on improving your boat. If you own a Yamaha outboard motor, look into Yamaha 20 & 100-hour service maintenance kits. Shop for all your boat parts, produces, and boating essentials at PartsVu.