Best Outboards For Repowering In 2021: How To Choose

Choosing the Best Outboards For Repowering In 2021

When choosing the best outboards for repowering your boat you have a similar set of factors to address as those we examine in 5 Tips for Repowering your Boat, which focuses mostly on inboards and stern drives, but some additional items to take into consideration. The eventual value of the boat, installation issues, and warranties certainly come into play regardless of what type of power system you’re replacing, but when considering a new outboard for repower additional major factors you’ll face also include:

  • Outboard engine horsepower
  • Outboard engine weight
  • Costs of an outboard
  • Outboard engine controls and accessories

How Much Horsepower

Just how powerful an outboard you want for your repower depends on how happy you were with the boat’s performance with the existing amount of power. Obviously, if the boat always seemed a bit underwhelming, you may want to up the ante. This is, however, also an opportunity to upgrade the boat rather than merely replacing what you already had. Would another 50 or even horses be fun to utilize, even if it’s not “necessary”? If so, now’s your chance to make it happen.

In today’s day and age, repowering may also give you the opportunity to go from a single to twins, or conversely, from twins to a single. Single engines require less maintenance and tend to be more efficient than twin engine rigs. In 2021, you can replace a pair of 200-horsepower outboards with a single Yamaha F425 XTO outboard without changing the weight on the transom by more than about 20 pounds. Yet you’ll have a bit more horsepower, less drag, and likely see increased top-end and efficiency. There are, by the way, plenty of F425s listed among the Yamaha outboard motors on BoatTrader. Another example can be found in the new-for-2021 Mercury V12 600-hp Verado outboard.

Although repowering with a mega-motor like this will require also replacing additional systems like controls and monitors, you’ll not only enjoy gobs of power but will also benefit from all the new tech packaged into this cutting-edge powerplant, like contra-rotating propellers, an enhanced steering range, and the marine industry’s first two-speed transmission for outboards.

A pair of twin Mercury Verado 250 HP outboards gives the E-29 XS plenty of pep.

Outboard Engine Weight

Along with power comes weight, and in some cases, weight can be reduced. But in others it may increase. Reductions in weight are almost always beneficial, and increases may or may not have a significant negative impact. While this used to be a big problem when replacing older two-strokes with four-stroke outboards, modern four-strokes have shaved off much of that additional weight. It can still, however, be an issue in some cases. Take that Mercury 600, for example. Replacing a pair of 300-hp Mercury outboard with one could add as much as 200 pounds to the transom. Or let’s say you want to upgrade from a Suzuki DF300B to a DF350A. Getting the additional 50 horsepower will add about 150 pounds more weight.

Just how can you determine if your boat can take additional weight with a repower? The best method is on-the-water testing with simulated weight. Five-gallon buckets of water weigh about 40 pounds each when full, so you can line up as many as necessary along the transom and then run the boat with its existing powerplant to see how the boat responds to the additional weight.

Costs Of An Outboard

Just how much the cost of a new outboard comes into play will differ from person to person, but one thing is for sure: while repowering a boat with a new outboard engine will increase your boat’s resale value substantially, it probably won’t increase it as much as the price of the new engine. Like cars, the moment you sign on the dotted line, devaluation has to be expected. Of course, this is just as true when you buy a completely new boat. In the long run, we just have to remind ourselves that boats and outboards are depreciating assets — we don’t buy them because it’s a good financial move, we buy them because we love them. And once that new outboard engine is hanging from your boat’s transom you’re bound to be a happier boater.

That said, there are some ways to save money when repowering. If you choose a brand and size outboard that are the same as the old one, you may be able to re-use the gauges and/or engine monitors and the steering and control systems. You may also be able to use the same propeller. DIY boaters who are competent mechanics can save on the cost of mounting by doing it themselves, although before doing so you should check the manufacturer’s warranty to make sure this won’t void it. And in some cases, switching brands or down-sizing the engine can result in a significant cost savings.

Outboard Engine Controls and Accessories

One of the often-overlooked benefits to repowering with an outboard is the enhanced functionality and ease of use you can also enjoy with new controls. True, in some cases you may want to re-use them to save on cost. But in situations where major advancements have been made, switching to new controls can have major-league benefits. The new Suzuki DF 115A and DF140A present perfect examples. Prior to 2021 these engines were available with mechanical controls, only. But now the new DF115B and DF140B versions can be had with drive-by-wire controls. That makes shifting smoother, throttle response instantaneous, and rigging simpler.

In some cases, going with new control systems can also vastly enhance the handling and performance you enjoy. If you can upgrade to include the Yamaha Helm Master EX system, for example, joystick steering becomes possible. You’ll have far better dockside handling, autopilot becomes integrated, and anglers can benefit from features like Set Point, which utilize GPS to maintain the boat’s position or control its drift.

Repowering with a new outboard system can also incorporate digital engine monitors, which are a huge upgrade from old analog systems. You’ll know exactly how many RPM your outboard is turning at any given moment, you can bring up useful information like fuel burn and miles to the gallon, and you’ll have access to critical data like fault codes. You’ll often be able to bring up this data on your MFD as well, and sometimes, even on your cell phone via an app.

How to Choose the Best Outboards For Repowering In 2021

Armed with this knowledge, you should be able to make a smart choice when repowering with an outboard in 2021. For more information on the models mentioned above and on all current outboard offerings, visit Honda Marine, Mercury Marine, Suzuki Marine, Yamaha Outboards and Tohatsu Outboards.

Written by: Lenny Rudow

With over two decades of experience in marine journalism, Lenny Rudow has contributed to publications including YachtWorld,, Boating Magazine, Marlin Magazine, Boating World, Saltwater Sportsman, Texas Fish & Game, and many others. Lenny is a graduate of the Westlawn School of Yacht Design, and he has won numerous BWI and OWAA writing awards.


2021 Bayliner VR6 OB Bowrider Boat
Self-Bailing Boats: The Complete Scoop
Category: Boating
Just what are self-bailing boats, how do they work? Lenny Rudow investigates why they are important.