Outboard Engines: The 8- to 15-hp Sweet Spot

A Ted Williams 9.9-horsepower, two-stroke outboard was the engine that many of my childhood memories are wrapped around. Whether it was crabbing the Chesapeake Bay with my father or shooting the Indian River Inlet to go fishing, that engine faithfully pushed our little fiberglass skiff wherever we wanted to go, despite how poorly we treated it. It was a true workhorse.

This 15-horse Suzuki outboard is a great powerplant for this youngster’s 14-foot skiff. Photo by Lenny Rudow

This 15-horse Suzuki outboard is a great powerplant for this youngster’s 14-foot skiff. Photo by Lenny Rudow

But the same “workhorse” status can be attributed to most any outboard in the 8- to 15-horsepower slot.  It’s the proverbial sweet spot, serving many different types of watercraft involved in a variety of activities. Whether it’s an auxiliary kicker on a sailboat; the primary source of power on an inflatable tender; or what makes the family skiff go, small outboards are the superheroes of the boating world.

With that in mind, let’s have a look at some of the applications for these engines, as well as some of the notable manufacturers that produce them.

Honda was a pioneer in the four-stroke outboard business. Today the company manufactures a wide line of outboard engines that includes this 8-horsepower model. Photo courtesy of Honda.

Honda was a pioneer in the four-stroke outboard business. Today the company manufactures a wide line of outboard engines that includes this 8-horsepower model. Photo courtesy of Honda.

Sailboats

Having a dedicated gasoline or diesel inboard engine on a sailboat can be a distinct disadvantage. Besides being heavy, they require complicated fuel storage and supply systems, raw-water plumbing for cooling, and a shaft and propeller that create drag. That’s why it’s not uncommon to see racing and cruising sailboats shorter than 30 feet in length fitted with an outboard motor, usually the long-shaft versions.

While some sailboats have a fixed outboard motor well designed into the stern, others have—or can utilize—a fixed or adjustable outboard motor bracket on the transom. The idea behind the adjustable bracket is that it can be lowered when in use, and raised up to keep the engine out of the water when sailing, or not in use. Fixed brackets are cheaper, but generally require you to remove the outboard to get it out of the water—not very practical.

Smaller sailboats, or those that only need a push out to the racecourse and back, can generally get by with a smaller outboard, though you’ll most commonly see 8- and 9.9-horsepower models used as kickers. Outboard engines rated at 15 horsepower and up are generally too heavy for practical sailboat kicker use.

Tenders

If you’ve got a hard dinghy with the correct bottom profile you can generally use oars to get around pretty effectively. But factor in tidal currents, remote anchorages, or the urge to explore new harbors, and most folks find that rowing becomes unfeasible in anything but a dedicated “pulling boat.” That’s why you’ll see most hard-bottomed and inflatable dinghies fitted with a small outboard.

In addition to a large propeller, Mercury’s ProKicker outboards have improved gear ratios and beefier lower unit components. Photo courtesy of Mercury Marine.

In addition to a large propeller, Mercury’s ProKicker outboards have improved gear ratios and beefier lower unit components. Photo courtesy of Mercury Marine.

There are plenty of smaller dinghies around with outboards of six horsepower and less, but bigger dinghies, especially inflatables over eight feet in length—will utilize outboards rated at eight horsepower and above. Check the manufacturer’s specifications to find out the maximum horsepower rating for your hard-bottomed or inflatable dinghy before deciding on an engine.

Lastly, if you cruise with your dinghy and will have to haul it aboard the mother ship to stow, keep in mind that the lighter the outboard, the better. Your need for speed will evaporate quickly when it comes time to bend your back and lift a bigger outboard over the rail.

Skiffs

Most of us got infected with the boating bug in a skiff, whether it was an old aluminum jon boat or a beat-up example of the fiberglass or wood variety. And the portable nature of these beautiful small boats makes them the perfect platform for an 8- to 15-horsepower outboard.

Sizing the correct outboard often requires checking the maximum horsepower rating, as specified on the boat’s capacity plate. You can usually find the plate on the transom somewhere. But keep in mind that you don’t always have to go with the maximum. If you generally just poke in and out of creeks within a short distance from your home or the launch ramp, a smaller engine may suit you just fine. Larger engines provide more speed for covering longer distances, and often suit anglers who need to cover a lot of ground.

Fishing Boats

“Kickers,” as folks on fishing boats know them, are small outboard engines used to push a boat around at trolling speeds. The idea makes sense when you consider not just the fuel cost of running the boat’s big main engine, but also the hours you’ll put on it trolling a spread of lures or rigged bait, often for hours on end.

Evinrude’s portable four-stroke outboard lineup is actually manufactured by Tohatsu. The rest of Evinrude’s outboard range is comprised completely of two-stroke technology. Photo courtesy of Evinrude.

Evinrude’s portable four-stroke outboard lineup is actually manufactured by Tohatsu. The rest of Evinrude’s outboard range is comprised completely of two-stroke technology. Photo courtesy of Evinrude.

The size of the boat you run and the speed at which you need to troll will decide the size of kicker outboard you need to get, but boats under 25 or so feet in length can usually get away with a 9.9-horsepower outboard with a long shaft. Some anglers also opt for “high-thrust” versions, which include bigger props that throw more water—more bang for your buck. Larger fishing boats need bigger outboards, but 15 horsepower is usually the breaking point; that’s when simply running the primary engine for trolling makes more sense.

Now, to on to the players in the outboard market.

Yamaha

Yamaha’s portable range includes four-stroke gasoline outboards ranging from 2.5 to 20 horsepower. In the aforementioned sweet spot range, the company manufactures outboards of 8, 9.9, and 15 horsepower, in both long- and short-shaft configurations. Yamaha also produces a “high-thrust” 9.9-horsepower model, which provides up to twice the thrust of comparable 9.9 models, thanks to a large-diameter propeller.

Suzuki

While not as well-known as some other brands, Suzuki manufacturers some of the nicest and most durable outboards on the market. Suzuki’s portable lineup includes four-stroke gas outboards from 2.5 all the way up to 30 horsepower, with sweet spot engines of 9.9 and 15 horsepower in the mix. Like Yamaha, Suzuki also manufactures a high-thrust 9.9 model that’s great for pushing larger watercraft, such as sailboats, pontoons, or multispecies fishing boats.

Lehr’s outboard engines use efficient, clean-burning propane gas. Photo courtesy of Lehr.

Lehr’s outboard engines use efficient, clean-burning propane gas. Photo courtesy of Lehr.

Mercury Marine

A heavy-hitter in the four-stroke outboard game, Mercury Marine’s portable FourStroke model range includes two-cylinder outboards from 2.5 to 20 horsepower, with six models from 8 to 15 horsepower. Mercury’s 9.9-horsepower range includes not only a high-thrust model, but also a ProKicker unit that has better gear ratios, a heavier gear case, and a beefier skeg for the fishing-boat market. A 15-horse ProKicker model also is available.

Honda

Though Honda has been relatively quiet in recent years, when it comes to the introduction of new models, the company virtually invented the four-stroke outboard engine market back in the ’80s. While Honda’s small four-stroke outboards weren’t the first, they were the first that were commercially successful. Today the company builds all sorts of four-stroke outboards, but its portable range includes models from 2.3 to 20 horsepower. The 8- to 15-horse models round out middle section of that range, but notably missing is a high-thrust model.

Evinrude

You might be surprised to find out that two-stroke innovator Evinrude sells four-stroke outboard engines at all, much less a portable four-stroke outboard range starting at 3.5 hp and moving up to 15 horsepower. There’s no eight-horsepower model, but you can get either 9.8- or 15-horsepower flavors in long- and short-shaft versions. The best part? They’re quiet and smooth, with none of the smelly exhaust that small two-stroke outboards are known for.

Torqeedo’s Cruise 4.0R outboard produces the equivalent of about an 8-horsepower outboard. Photo courtesy of Torqeedo.

Torqeedo’s Cruise 4.0R outboard produces the equivalent of about an 8-horsepower outboard. Photo courtesy of Torqeedo.

Tohatsu

Tohatsu is an excellent place to continue the conversation, because…  those four-stroke Evinrude engines we just discussed? Yup, the two companies entered an agreement in 2011 for Tohatsu to supply Evinrude with parts of their portable four-stroke lineup. As a result, the portable Tohatsu lineup mirrors much of what Evinrude offers, with a few exceptions. Most notable, the Tohatsu lineup includes the 2.5-, 5-, and 8-horsepower models missing from Evinrude’s portable model range.

Lehr

You’re definitely cooking with gas when you run a Lehr outboard—literally — because they run on the same propane fuel most every backyard gas grill does. The result is a quiet, efficient outboard with far fewer emissions that normal gasoline outboard engines. And they have a fairly robust lineup of models to choose from.

Pick from 2.5-, 5-, 9.9-, 15- and 25-horsepower models, all available in long- or short-shaft iterations. The 2.5- and 5-horsepower models are unique in that you need only screw in a one-pound propane canister and you’re ready to go.

Torqeedo

You’ll need a bank of batteries to run an outboard from German manufacturer Torqeedo, but the company does offer an 8-horsepower equivalent in its electric outboard lineup. The Cruise 4.0R model comes in both long- and short-shaft versions, pushing 4,000 watts of clean electrical horsepower.

The 8-horsepower Yamaha outboard is a great match for this small aluminum skiff. Photo by Gary Reich.

The 8-horsepower Yamaha outboard is a great match for this small aluminum skiff. Photo by Gary Reich.

Conclusion

While engines in the lower end of the horsepower spectrum rarely get much press, they represent an awfully important piece of the boat propulsion pie. Whether you’re trolling for walleye or sprinting out to race around the buoys, outboards in the 8- to 15-horsepower range are as versatile as a Swiss Army Knife in terms of the jobs they can do.

 

Comments

  1. Jim Rabey says:

    I am looking for a 2.5 to 4 hp portable outboard. My transom is 16 1/2 inches. I also want to take to lakes and not haul a trailer. I need a light motor, I’m 70 years old, but in good health. I would like it to be less than 60 lbs. I would like your advice.
    Jim

  2. Gary Reich says:

    Hi Jim –

    Have a look at Mercury, Yamaha, and Tohatsu. They’re all four-strokes, which will keep things easy and all weigh within a few pounds of each other (37-60 pounds, along the whole horsepower range). Yamaha only has a 2.5 and 4, while Mercury and Tohatsu have 2.5, 3.5, and 4 models. You’ll want to pick a long-shaft model, given your transom height. The manufacturer’s websites all have dimensions and specifics.

    Enjoy – Gary

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