September 19, 2022
Repowering Your Outboard Boat
Repowering Your Outboard Boat

Repowering Your Outboard Boat


With the rising cost of living and ever-expanding inflation rates, avid boaters might be searching for ways to cut costs while still enjoying time out on the water. It’s no secret that new boats are expensive, so what do you do if your engine isn’t quite up to snuff anymore? Repowering your outboard boat might be just the answer you were searching for.

Repowering an engine is exactly what it sounds like, getting a new and better power source behind your boat. A repower can give you the feel of a brand new boat at a fraction of the cost. You can opt to rebuild your existing engine or look into purchasing a new one. A cost-efficient option, a repower is an excellent alternative to buying a new boat or continuing expensive maintenance on an aging engine.

Repowering your boat isn’t necessarily rocket science. However, no matter what your boating mechanic experience is, many boaters have questions about repowering. There are several factors to consider when discussing repowering a boat motor – cost, type of boating, horsepower, and warranty. So today, we will discuss the basics of repowering your outboard boat and answer some common questions. 


Repower Reasons


Most boaters opt to repower when their old engine becomes an unreliable mechanical headache or when they long for the speed and efficiency of a new engine. One of the biggest reasons is you simply love your boat; it handles like a dream, it’s perfectly rigged and accessorized to your likes, and it’s been well cared for. A repower might be an excellent option for you, especially if any of the following apply to your current outboard engine:

  • Your engine suddenly has a crazy appetite for fuel 
  • It is burning oil
  • There is excessive corrosion buildup.
  • Your engine is spending more time in the shop than on the boat.

No one wants to head out for a fun day on the lake with the nagging worry that their increasingly unreliable boat engine might break down. So when facing the question of repairing or repower ask yourself the following questions:

  • How old is the engine?
  • How many hours are on it?
  • What is its internal and external condition?


Repowering is usually your best option if the following apply:

  • The technology is out of date on your engine.
  • Repair parts are hard to find and pricy to purchase
  • The cost of repairs exceeds your engine’s value. 

Keep in mind that when boat engines are only run in freshwater, they tend to last longer. This is due to less corrosion and, in colder climates, a shorter boating season.

Finally, ask yourself and answer honestly:


What’s Your Boat’s Condition?


Before investing time, energy, and finances into a repower project, you want to ensure the boat is still in good condition. Ideally, you don’t want the cost to repower to exceed the value of your boat. We recommend spending the money on a good surveyor who can tell you your boat’s exact shape. How’s the laminate look? What about the stringers? Is there any water intrusion into the transom? A boat can look fantastic on the outside and be decaying on the inside. Finally, is your boat a desirable brand? Before undertaking your project, make sure your boat is worth it. 

The biggest roadblock for repower on fiberglass and aluminum boats is a bad transom. A good surveyor will let you know immediately if that’s the case. Many boat manufacturers did not realize until the mid-80s that polyester resin is water permeable, resulting in waterlogged boats. So boat manufacturers made the switch to vinyl ester resin. However, some manufacturers did not adopt this resin right away. A repower might not be for you if you have an older boat with a polyester resin coating.


Frequently Asked Questions About Repowering Your Boat


1. Can I upgrade my horsepower?


This is one of the first questions asked, as many boat owners have a need for speed. So let’s talk about how an outboard repower impacts your horsepower. First, you want to check your boat’s capacity plate for the rated horsepower. The old motor might already sit at the maximum horsepower for your boat. If that’s the case, then no horsepower upgrades are in your future. Well, what if the weight of the new, more powerful engine is the same as the old engine? The weight is not important; horsepower is the ultimate limiting factor. If your boat can handle more horsepower, it does have its advantages. The most obvious being your boat will go faster at the top end. While this is a benefit, the best part of more horsepower is cruise speed. 

A bigger engine, or engines, don’t work as hard or burn as much fuel to maintain the same cruise speed produced by the older, smaller outboards. As a result, the bigger engines generate more horsepower and produce faster cruise speeds when run at their optimum rpm. 

Despite all the benefits of more horsepower, the reality is that boats will perform their best at their maximum rated horsepower. In addition, you get the best fuel economy because the engine is not struggling. It is essential to never, under any circumstance, exceed the USCG-rated horsepower.


2. Should I Change My Engine’s Brand?


There are several reasons why changing your engine’s brand is a good choice for you. The most common is you are unhappy with your current brand’s performance, local dealer service, or warranty terms. If you are happy with all three of these components, there isn’t a big reason to change brands. However, if you want to switch and try something new, check in with your local dealer and get a good idea of the engine’s brand, the service for the brand, and the warranty. 

In addition, take into consideration that changing engine brands will most likely require re-rigging the boat. However, this isn’t a massive downside as it is a good idea to do this anyway when you update your engine. See point five for more detail on this!


3. Is Two Really Better Than One?


Due to the improved reliability and the increased power output in many of today’s outboards, sometimes it is best to opt for a single large engine instead of two smaller engines. However, adding another outboard is generally not advised by professionals. For example, Jason Eckman, product manager of Evinrude (a quality manufacturer of outboard motors for boats), recommends against changing the number of outboards. He notes that it is a very complex process and usually involves lots of fiberglass work to prep the transom for such a drastic switch. Not only that, but the addition of another outboard can add too much weight to the stern. Finally, the transom might not have the structural support to accommodate another engine safely.

On the flip side, checking with your boat model’s manufacturer is important. Check to see if your model’s transom can handle extra power bolted to a smaller central location with one engine versus having it spread across the boat’s stern with two engines.

Additionally, while technology has vastly improved today’s engines, making them unlikely to break down, the comfort of an additional engine might provide more peace of mind if you travel far offshore. 


4. Two Stroke of Four Stroke


The original four-stroke engines of the 1980s had better fuel economy, but were also heavier, required more maintenance, and had weak low-end torque. 

Luckily, that is no longer the case. As technology advances, two- and four-strokes are approaching an equal playing field in the engine realm. So now, it more comes down to selecting an engine that helps your boat perform at its best and maximizes its individual value. 

Here are a few key considerations to consider when trying to make a selection:

  • Two-stroke outboards trump four-stroke outboards regarding low and mid-RPM range torque (AKA, they can get up and go fast!). A two-stroke is the way to go if you are an avid bass angler or towing-sport enthusiast. In addition, most two-strokes can compete with many four-stroke engines when it comes to fuel economy.
  • Four-stroke engines are now lighter and have an improved mid-range torque.
  • Most outboard engines have a fuel injection system instead of a carburetor. While some outboard makers inject the fuel into the intake manifold, others inject it into the cylinder. Regardless, new fuel injection systems mean the engine is more reliable and fuel-efficient than its older carburetor counterparts. 


5. Do I Need New Controls and Instruments?


The short answer is not necessarily. However, the reality is since you are repowering, chances are high that the engine you are replacing has outdated cable steering and throttle control. A big reason to repower is to get rid of the old-fashioned system. Updating everything, including the steering, throttle, shift, cables, electrical harnesses, battery cables, and instruments, is an excellent idea. You don’t want to struggle with an old, worn steering system or old controls and gauges with your new engine. If you see the price tag increasing, don’t worry. Certain manufacturers, like Evinrude, offer a conversion solution. Suppose you need to save money on installation. In that case, Evinrude has a “conversion module” which takes existing cables and puts them into a box that converts mechanical control movements to digital signals. 

In addition, technology has advanced considerably in the past ten years – especially concerning digital instrumentation. The new technology offers information, like fuel consumption and the best speed for fuel efficiency, that old gauges simply can’t provide.


6. How About A Joystick Control?


All major outboard manufacturers have joystick controls for multi-engine installations. Making docking and tight situations easier to navigate, you might want to consider installing one. However, some original-equipment manufacturer systems do not have joystick controls for aftermarket installation. So, if a joystick is important to you, ensure the option you choose includes a joystick.

The choice to add it as part of your repower project boils down to three key things:

  • First, you need to have multiple outboards because a joystick system won’t work with a single engine
  • Second, you need to take into consideration your level of experience and the size of your boat. A joystick can save you embarrassment and stress if you are not confident in docking your boat.
  • Finally, consider the price. Adding a system that includes a joystick can boost your price point. A joystick system might not be for you if you want to repower your outboard due to budget constraints. 


7. Is It A Good Idea To Install New Fuel-System Components?


The short answer is yes. It is vital for your and the boat’s safety to update fuel-system components regularly. Many experts recommend boaters replace all of the boat’s fuel hoses with new Coast Guard-approved, ethanol-resistant hoses every time they do a repower.

In addition, if you decide to upgrade your horsepower, check the engine manufacturer’s specifications to ensure you install a fuel hose and fittings with inside diameters large enough to sustain the new engine’s fuel needs.


Final Thoughts


Repowering your outboard boat can be an excellent option if you love your current boat and model but are ready for an upgrade in technology and power. Here at Rocket Marine, we have years of experience and knowledge concerning all things boats. We offer quality trailers so your recently repowered outboard boat can ride in style. In addition, we have decades of experience, advice, and quality mechanics to meet all of your boating needs. Contact us to see how our incredible boating team can help you! 


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Published: September 19, 2022
Author: Rocket Trailers
Categories: Uncategorized