Dinghy Engines

The light, easy-to-start Honda BF2 fends off challenges from 3 newcomers.


Editor’s note: Although many of the engines profiled in this archive report have changed since it was first published in 2006, many of these engines are still in circulation on the used market and the same features are found in the newer models. In addition, some of the changes have not been very significant, so the report will still hold some value—as will the links at the bottom. Our most recent reports on a range of outboard engines can be found by using the search bar, try “outboard engine,” or “dinghy engine.” If there is a new outboard you’d like to see tested leave a comment below. 

Few things are more frustrating than pulling fruitlessly on the start cord of a stubborn outboard, or paddling your dinghy (and the $1,000 outboard strapped to its stern) back to your boat. The gradual shift away from two-stroke engines to the more durable four-stroke variety has reduced the likelihood of these moments. But the four-stroke portable engines (December 1 and March 1, 2003, and in March 2015) we’ve tested over the last three years, 4- and 8-horsepower models, are big and heavy. The 8-horsepower engines, which can exceed 80 pounds, can’t even be considered truly portable. The 4-horsepower models (about 55 pounds) are easier on the back, but it’s still no fun to wrestle these engines on and off the transom.

Dinghy Engines
From left to right, the Yamaha F2.5, the Mercury 2.5, the Tohatsu MFS 2, the Honda BF2, and the Suzuki DF2.5.

Until recently, pickins have been slim if you wanted a lighter, compact four-stroke: the Honda 2 and the Yamaha 2.5. But three super-small four-strokes from Suzuki, Tohatsu, and Mercury hit the market this year, giving consumers a wider range of choices.

We rounded up all of the 2- and 2.5-horsepower four-strokes available on the market: the Honda BF2, the Yamaha F2.5, the Suzuki DF2.5, the Mercury 2.5, and the Tohatsu MFS2. The Honda and the Yamaha are the most expensive, with retail prices of about $1,000. The Mercury carries the lowest MSRP ($855), followed by the Tohatsu ($927), and the Suzuki ($955). All are 15-inch shaft models.

PS used a Walker Bay RID 275R to test the five engines. A review of this 9-foot, hard-plastic dinghy appears in the November 2003 issue. The Walker Bay uses an inflatable tube around its exterior for stability when the boat is fully loaded. It weighs 89 pounds, has a beam of 5 feet, 8 inches, and is rated for up to a 4-horsepower outboard. The boat can be fitted with either a PVC or Hypalon tube. (Cost: $860 with the PVC tube; $1,200 with the Hypalon tube.)

The test site was a saltwater basin just south of Tampa Bay, Fla. We used a friends waterfront dock as a staging ground for the test. Testers fixed a 2-inch by 8-inch board be-tween two of the docks pilings, so all five engines could be mounted side by side. We examined all components and critical access areas, including oil fill and oil dip stick, carrying handles, tillers, throttles, forward/reverse shifts, cowlings and their clips and fasteners, and ease of tilting, etc. Testers then moved the engines to a second 2 x 8 mounted just a few feet above the water (pictured above). There, the engines were started and run through part of their break-in periods. Testers also evaluated ease of starting at this point.

Once the engines were broken in, they were mounted one at a time on the Walker Bay for speed and noise testing, which took place with two people on board. Speed and noise data were recorded at idle, half-throttle, and full-throttle settings. Interestingly, there was no difference with any of the engines in thrust or speed, at half throttle and full throttle. Therefore, only idle and full-throttle numbers appear in the chart on page 26. Speed and noise levels were taken in two directions and averaged to account for wind and current.

We had three testers (two men and one woman) start each engine to assess smoothness and ease of starting. They mounted, lowered, and tilted the engines, then operated them on the boat, and finally removed them from the boat. This gave testers a start-to-finish experience with each motor. At the rate these small units burn fuel, any gas economy advantage would be negligible, so we did not test fuel consumption.

When we weighed each engine, all but the Mercury  (4 pounds over its listed weight) and Tohatsu (2.5 pounds over its listed weight) were within a pound of their published weight.

The weights of these mini motors ranged from 29 to 42 pounds. These are all one-cylinder engines with pull starts and integral fuel tanks that hold about a quart of gas. The engines require only about 10 ounces of oil, and the gear cases even less than that. Four of the five engines carry the three-star exhaust emissions rating (the best you can get). The Yamaha has a lower, two-star rating, which is defined as very low emissions.

All are water-cooled engines except for the Honda, which is air-cooled, meaning it runs louder than water-cooled engines but doesn’t need to be flushed with freshwater. The others have water pumps that must be replaced, typically at 100 hours.

As is the case with all portable four-strokes, these engines must be stored in a particular position to prevent engine damage resulting from oil draining out of the crankcase. All can be stored in the upright position or on one specific side. The Yamaha can also be stored resting on its face with the prop up. It has built-in resting pads on the front of the engine specifically for this purpose.

The Honda was the only engine with a centrifugal clutch rather than a separate shift lever. Simply turning the throttle executes the transition from neutral to forward. The other four engines have starboard side gear levers with neutral and forward positions.

Another commonality: All five have oil-check windows. All except the Yamahas are viewable without removing the cowling.

All of these engines have tilt support pins that are used to you guessed it support the engine when its in the tilted position. The Mercury and Tohatsu pins are easiest to operate you simply pull them out, tilt up the engine, and push it in.

Testers found minimal variations among the engines in speed. The extra 0.5 horsepower of the Mercury, Suzuki, and Yamaha had little to no effect on speed. We didn’t measure thrust, but testers reported that no engine had more umph than another. There were some differences in noise levels, which we will address in each product review.

Testers noted significant distinctions while carrying, mounting, and starting the engines. (All have chokes, stop buttons and kill switches with lanyards.) Differences in throttle operation and ease of tilting are also noted below.

The Suzuki, which was introduced earlier this year, and the Honda are the lightest and most compact engines tested.

Testers were disappointed with the Suzuki’s thin handles for its clamp screws. They’re nothing more than 2-inch-long metal pins. The DF2.5 has a nice grab handle in the front, but the back of the engine has no handles, so carrying the engine in an upright position is awkward, in our opinion. There’s no recessed handhold area in the top of the cowlings backside for tilting and lowering the engine once it is mounted on the boat.

Two rubber straps are used to secure the cowling. They can become slippery and difficult to hook and unhook if your hands are wet or greasy.

The starboard gear shift is smaller than we prefer, and testers said it was harder to reach than the other three models with shifts.

The Suzuki must be stowed on its port side, so it lies on the elbow of the tiller and a case protector (a bump in the cowling).

The Suzuki was the second-loudest engine in the group. We recorded 97 decibels at wide-open throttle (WOT), which is only two decibels short of the air-cooled Honda. Noise levels at idle 77 decibels were also higher than the other water-cooled models.

Testers gave the Suzuki a Fair for ease of starting because the engine had a strong recoil effect. Each owners manual directs users to pull the cord slowly until resistance is felt, then pull the cord briskly to start. If this first step is not taken and the cord is pulled vigorously from its original position, it can recoil or snap back and pull your hand back toward the engine. This recoil effect was most prominent with the Suzuki, it happened a couple of times to our testers while starting it. It is absolutely necessary to follow the starting instructions.

The owners manual calls for engine and gear case oil changes at 100 hours, and spark plug and water pump replacement at 200 hours.

Bottom Line: The attractively priced Suzuki is light, but its loud and needs beefier mounting clamps and a backside carrying handle. Starting the engine can be tricky.

The Yamaha is eight pounds heavier than both the Suzuki and the Honda, but five pounds lighter than the Mercury and Tohatsu.

Testers didn’t mind the Yamaha’s traditional, floppy-ear-clamp style mounting screws. They also thought this engine had the best means of securing its cowling: two large clips, one on the back and one on the front. Theres no recessed handhold area on the cowling top to make it easier to pull the engine out of the water, however. For carrying the engine in a vertical position, there is a handle on the back and a recessed area below the front cowling clip. The Yamaha must be stored on the tiller side or face-down with the prop facing up (as noted earlier). It has no cover protector, and the manual suggests placing a towel under the engine to prevent scratches.

Testers liked the large gear shift, and reported that it moved smoothly in and out of forward. Its also a few inches farther forward than the Suzukis, making it easier to reach. The Yamaha, Tohatsu, and Mercury have longer tillers and larger  throttle grips than the Honda and Suzuki.

The Yamaha was a smooth starter, and it was among the quieter engines in the group. In fact, it had the best score at WOT: 91 decibels.

The manual calls for engine and gear case oil changes at 100 hours, and spark plug and water pump replacement at 200 hours. The manual needs a better illustration to identify the oil plug drain, in our opinion.

Bottom Line: The Yamaha is easy to start and shift, and we like the longer tiller. Its also relatively quiet. On the downside, its the second most expensive motor, requires tiller-side horizontal storage, the cowling must be removed to see the oil inspection port, and it has a lower emissions rating.


The Honda is the most expensive engine tested. Honda and the Suzuki are the same weight, and roughly the same size, but the Honda is equipped with better carrying handles, in our opinion. It has a handle on the front and a recessed area below the backside of the cowling. It was by far the easiest engine to transport from dock to boat and back.

On the other hand, the Hondas cowling was the toughest to reinstall. The cowling is too flexible, and positioning its two metal tabs into slots on the engines front is tricky (the back is secured with a rubber strap similar to the type on the Suzuki). If the tabs aren’t in correctly, the backside of the cowling wont fit properly. When we returned the engine to the Honda dealer, he set us straight, showing us how to make it work.

Handles for the mounting screws are double-ended eyebolts. These  are easy to padlock and will likely last longer than the floppy ear types.

The engine can be stored on two hard-plastic case protectors on the starboard side. The protectors are larger than on the other motors so the engine is more stable, and they are ribbed for better traction.

The Honda was easy to start. At first, testers found the centrifugal clutch awkward, but quickly grew to like it, and ended up preferring it over the engines with a separate gear shift. The clutch allows the driver to hop back and fourth from forward to neutral. This is very useful while pulling the dinghy up to a dock or its mother ship.

The manual states that some of the clutch components should be replaced after 150 hours. The technical staff at Defender Industries in Waterford, Conn., a large seller of small engines and boats, tell us that this practice is rarely done. Mechanics there have never had to replace a clutch.

Downsides: The Honda has the shortest tiller and it was the loudest engine. In addition, the BF2 is the most expensive. The manual calls for more frequent oil changes every 50 hours than the others.

Bottom Line: It is loud and its the most expensive engine tested. But the Honda is still our top pick because it excels in the areas we think are most important weight, portability, storage, and starting. Plus, you don’t have to flush it.

The Mercury 2.5 and Tohatsu MFS2 are identical in size and shape, but Mercury points out that its engine is not just a rebranded product. The 2.5 is a joint development effort between Mercury and Tohatsu, with Mercury engineers as fully involved in the design as Tohatsus, said Mercury spokesman Erik Pope. The product is then manufactured by TMC, the joint venture company that manufactures the product for both companies. Differentiation in horsepower is obtained through different carburetor geometry.

The two engines are noticeably larger and heavier than the three others, and therefore they were harder to carry and mount on the dinghy. The Mercury is the least expensive engine, and the Tohatsu is only about $50 more than the Mercury.

The Tohatsu and Mercury have identical systems of securing the cowlings: Both have a single clip on the back and the front is held in place with a single tab that slides into a recessed area on the lower cover. They lack a recessed area or handle on the back, which makes carrying these engines in a vertical position difficult. The Mercury and Tohatsu have the same floppy-ear style handles on their mounting screws as the Yamaha.

Like the Honda, the Mercury and Tohatsu can be stored horizontally on their starboard sides, resting on two cover protectors for stable stowage.

The Mercury was very easy to start. One tester did not have the strength to start the Tohatsu, however. We like the long tillers and large, grippy throttles on these engines. The large shift levers that are close to the front of the engine are easy to reach.

The Mercury is rated at 2.5 horsepower compared to the Tohatsus 2 horsepower, but the Mercury pushed the dinghy only one-10th of a knot faster that the Tohatsu at WOT. Noise levels were nearly identical as well. Both engines, along with the Yamaha, were much quieter than the Suzuki and Honda. Overall, they ran slightly smoother than the other engines, but both the Mercury and Tohatsu made a slight rattling sound at idle. Mercury said the engine we tested is a prototype and that the rattling issue has been corrected.

The Mercury manual instructs the user to replace the engine and gear case oil and spark plug at 100 hours. At the same time, a dealer should replace the water pump and lube the splines on the driveshaft. The Tohatsu manual calls for the same maintenance but says nothing about lubing the driveshaft.

Bottom Line: They’re larger and heavier than the others, but we like their long tillers, large shift levers, and simple tilt support pins. The Mercury, which has the lowest price and was easier to start than the Tohatsu, earns Budget Buy honors.

If light weight is a priority, then the larger, heavier models from Mercury and Tohatsu are not for you. However, if the engine will spend long periods of time on the dinghy, the low-priced Mercury is an attractive option, in our view. Its a smooth-starting, relatively quiet engine with a long tiller and comfortable throttle. Our test engine rattled a bit at idle that’s the only performance drawback. The Tohatsu was harder to start, and it has a higher retail price, so wed go with the Mercury.

Among the smaller engines, the Honda is our top choice. Considering all of its positives (lightweight, compact, easy to stow, easy to start, and centrifugal clutch), we can deal with its noisier operation, short tiller, and fussy cowling. The Suzuki and the Yamaha have some significant pluses, but they come up short in too many areas that are important to us.



yamaha-motor.com, 770/497-6400




Darrell Nicholson
Practical Sailor has been independently testing and reporting on sailboats and sailing gear for more than 50 years. Supported entirely by subscribers, Practical Sailor accepts no advertising. Its independent tests are carried out by experienced sailors and marine industry professionals dedicated to providing objective evaluation and reporting about boats, gear, and the skills required to cross oceans. Practical Sailor is edited by Darrell Nicholson, a long-time liveaboard sailor and trans-Pacific cruiser who has been director of Belvoir Media Group's marine division since 2005. He holds a U.S. Coast Guard 100-ton Master license, has logged tens of thousands of miles in three oceans, and has skippered everything from pilot boats to day charter cats. His weekly blog Inside Practical Sailor offers an inside look at current research and gear tests at Practical Sailor, while his award-winning column,"Rhumb Lines," tracks boating trends and reflects upon the sailing life. He sails a Sparkman & Stephens-designed Yankee 30 out of St. Petersburg, Florida. You can reach him by email at practicalsailor@belvoir.com.


  1. I found the new 4 stroke wet sump outboards impossible heavy when it came time to replace my Yamaha 2 stroke back in 2008. It weights just over 30 pounds. So, I had it completely rebuilt for half the cost of one of the over weight 4 strokes. It still runs although it is long sold.

    We alos carried a Yamaha 15 2 stroke which was bullet proof and we had a small davit to lower it onto the dingy once the dinghy was along side. That motor was used for higher speed exploration, diving etc. The put put was used for all close in work: supplies from the dock etc.

    It is about time the cleaner 4 strokes have been developed which are of similar weight to the old 2 stoke 2 HP types. Been a long time coming. I’d only choose one weighing less than 35 pound though.

    In you article, a comparative stable of specifics would have been useful. Weight is the driving factor in this selection.

  2. We had the Honda and loved it except:
    Honda seemed to have designed this outboard for fresh water lakes. All the bolts rust heavily and are impossible to remove after a couple of years of cruising on the ocean. making rebuilding the outboard near impossible. The rebuild is usually needed after the valve cover Rusts through leaking all the engine oil. This requiring a rebuild.

  3. Why are you wasting our time with a fourteen-year-old article? If you won’t revisit the research, at least preface the article with a paragraph reviewing the market. You should report whether these models are still available or have been replaced. This facile regurgitation of an obsolete report is a shoddy abdication of the work for which we subscribe.
    Notes: Google showed that the Suzuki is two-cylinder, not one. The Yamaha has been completely redesigned, obviating completely this report.
    When ten minutes of review can point out your errors, why are you not doing it?

  4. ALL the small 4 strokes (3.5 HP or less) have a fatal flaw: the carbs get gummed up if they are left sitting with fuel in them for more than a week. Ultra small venturis are the problem. I am surprised PS failed to mention this. Sold my Merc 3.5 for a Torqeedo. Buy an old 2 stroke or a new electric.

  5. Another great option is the Lehr 2.5 hp propane engine. I’ve had mine for a few years and love it. No need to introduce gasoline handling and storage onto the boat and the propane camping cylinders are readily available. They are the same that are used for most marine rail-mounted grills, so many people are already carrying them onboard. The engine often sits for extended periods without use and always starts with no hassles since propane does not gum up carbs the way gasoline does. Compared to electric, the purchase price is cheaper and there is no range limitation other than how many propane canisters you choose to carry.

  6. Sailing was our major relief from the virus last summer, but I’d prefer to anchor out or find a mooring. A reliable, effective outboard is key to not having to spend hundreds of dollars renting slips.

    In my experience however, these gasoline outboards always start in the test tank and almost never start when strapped onto my 9′ Dyer Dhow! Not to mention the klutzy and often risky maneuvers manhandling the thing up and down from the rail of my Sabre 38 into the dink.

    The British Seagull mentioned above was surely a lightweight marvel (even with its propensity to vibrate itself right off the dinghy transom and into the drink … why they insisted on a lanyard!)) Since that’s no longer an alternative, I’m going to spring for an electric kicker.

    Not the cumbersome and heavy Torqueedo, though.

    This EP product https://www.electricpaddle.com/shop.html looks as if it will do the trick. Incredibly light and convenient, and less costly than the other electrics.

    Can’t wait for summer!

  7. I was looking at propane, but several mechanics warned me off the Lehr. Mercury and Tohatsu offer a 5HP propane that is essentially the same engine rebranded, and its reliability is said to be better. The drawback is that the Merc/Tohatsu only use external propane tanks, not the camping cylinders. You are back to storing a potential fire hazard.
    I too went electric. I have an ePropulsion Spirit Plus that incorporates some of the upgrades Torqeedo is just now putting into their equivalent motor (3HP). The electrics all have reverse gears, ideal for use as pushers for smallish sailboats, whereas no gas or propane motor under 5HP has a reverse, to my knowledge. Both have sufficient torque, and quiet ain’t enough to describe them. The batteries detach, making charging easier, and the whole package more manageable. The ePropulsion battery floats, as well. For liveaboards, I suspect the charging would be a challenge, and it must be said that both brands are twice the price of conventional outboards. You probably won’t get that price difference back over the life of the motors, but you will no longer start the season cursing and wiping oil off your hands as you try to get the kicker to turn over.

  8. Agree with JV Butler on the Yamaha 2 strike 4 hp model. I have run small hp 2 stroke Johnsons for 65 years (still have a ’57 7.5 hp for Northern lake fishing) My Yamaha is bullet proof with full gear shift, weighs 48# (yes, I use my motor lift to mount it on dinghy when on boat), runs smoothly, 100 x 1 gas oil mix. Like all small engines, all brands 2 & 4 strokes, are subject to ethanol gas caused carburetor problems. My Yamaha has been dealer serviced twice for not starting when I hadn’t run out the fuel after use. In both cases the dealers wanted to buy the engine from me because they thought so much of the 2 stoike 4hp. Now I religiously use labeled ethanol free fuel (if it truly is), use ethanol reducing additive, and most importantly, run out the fuel (after turning off fuel petcock) after every use, even if going to use again same day. I tried an older 7.5 hp Honda 4 stroke, but it was heavy, had to be stored in certain orientations, and had no guts / torque. My 6 hp Johnson 2 stroke ran circles around it. Give me a good old 2 stroke that can be stored any old way, has more power per hp, and is cheap to buy. A thousand dollars for a 2hp… you’ve got to be kidding me… Oh, and forget about a single cylinder engine.

  9. This is the first comment I’ve ever heard someone say 4 stroke outboards are more durable than 2 strokes. We have a 2004 Mercury 9.9 – stroke and a 2014 Yamaha 15 hp – 2 stroke. Other than routine maintenance and occasionally cleaning water out of the carb they run flawlessly compared to the previous Yamaha 4 stroke we used. Would never go back to a 4 stroke unless there were no other options.

  10. purchased a Mercury 3.5 as my old Yamaha was no longer serviceable. Did not start out of the box. Took it to dealer, he said and showed me it started. Took it to the boat, mounted on dink, would not start. Took it to dealer; he said carb gummed up. Not covered by warranty. Told by dealer to use avaition fuel as no alcohol. Mercury support says the do not recommend it. More meddling by the government and the greens. I wish I had kept that British Seagull. It was dependable, light weight and always started. So what if it was loud.
    A difference of a few pounds plus or minus is not an issue at all. I have a hoist on the stern to lift and lower it.
    PS should update their testing. Motor is still hard to start. Dealer also said to advance throttle position when starting and not have it on start.

  11. I have been comparing the electric and gas outboards on my own and one feature to adress is the amount of vibration introduced by the gas motor piston violently moving back-and-forth, the single cylinder particularly. The electric out boards I’ve tried are quiet. They allow conversation in the dinghy and I feel much closer to the natural world. Sstill trying to resolve charging in range problems

  12. I’ve used an ePropulsion “carry” model a couple of seasons, now. A VERY well thought out piece of gear.
    I always carry 2 batteries with it, but haven’t had to switch. Since our boat is solar-sufficient to our needs, there’s no problem recharging. Easy to load aboard, clean handling, very easy maintenance. Excellent response/ back-up from the maker.
    However, throttle/shifter can be tricky: one should use the safety-strap-kill-switch to be on the safe side. And while it is quiet, it is not silent.

  13. I have had cruising experience with a Honda 2hp, 4s, (2002) and a Yamaha 4hp 4s. (2006) and currently Merc 5hp 2s (2016).
    The Honda was reliable.
    rebuilt and even replaced carburator over the 4 years I had it. Fuel filter had to come from states.
    Serious problem noted earlier is that mild steel fasteners are used, and make it unsuitable for cruising. They rust from not wrenchable to disintegrate in a couple years. Great for fresh water.

    Yamaha 4hp 4stroke. bought new. Continual problems with jets clogging. A lot of fine residue of orange dust percipitates from fuel and continually clogs jets. Sometimes crossing a choppy anchorage. only cure was to pull the carb and clear jets. Try that bouncing around. Got rid of it only 4years old, when it quit right in front of a work boat leaving a marina at night. Close call (traded it for the Honda). The clips that hold the cover fall off

    when handling, and sink of course.
    Very quiet, and burned very little gas, but each time I had to clear the carburator, A noticeable bit of fuel escaped into the water.

    The Merc, (2016) 5hp. 2 stroke. So far experience has been flawless. Used it very frequently in Bahia del Sol El Salvador. No idea how many hours, buy quite a few. I haven’t even changed the plug, but have pulled it to inspect clean and regap. Only a few pounds heavier than the Honda, but much peppier.

  14. We have been full time cruising for 9 years and no serious long distance cruiser uses a 4 stroke. The 2 stroke, is lighter and more dependable, contrary to the authors claim. We saw more than one cruiser sell their new when they left the US 4 strokes for foreign market 2 strokes. You can buy the yamaha 2 strokes in most places outside the US (closest being the Bahamas) and we bought a Mercury Japanese market 2 stroke in NZ. If you can get a 2 stroke we would recommend it.

  15. The increased size and mass of four strokes are my biggest problem with them. Our Tylercraft 29 was designed for a 15 HP two stroke installed in a well, which was replaced by a 9.9 long shaft designed for sailboats. This worked well enough until the time to replace came around. Short of rebuilding the stern of the boat our only option was to use a 6 HP Tohatsu as there was no other four stroke that could possibly fit. The weight of anything with more horses would put the vessel down at the stern and out of trim.

    Although a tight fit, the Tohatsu works very well but was short of the power we desired for occasional adverse wind/sea/tide conditions. Eventually we did rebuild the motor well to improve access to the motor, but still have to planaround lack of power.

  16. The author remarks that small four strokes are more reliable than two strokes??? No.
    Our 25 year old Yamaha 25 2t is much lighter than the new four stroke offering, even though the newest one is closer. It starts first pull 98% of the time. We have e start, but LiPo motorcycle battery failed, and pull starting works fine. I have haven’t even changed the plugs the past three years. It will plane our 12’ dinghy with five large people, it guzzles gas, smokes in startup, and I have had four people offer to buy it on the dock. Not selling. I would like a greener alternative, but seeing dead four strokes and dead Torqueedos in Caribbean dumpsters that have been replaced by Yamaha 15 2ts helps assuage my guilt.