A while ago I posted the
Torqeedo 403 Ultralight Motor / Hobie TI Application Guide. This review outlined my experience in installing and using the Torqeedo 403 electric outboard motor. Almost immediately posts appeared comparing and contrasting this motor to gasoline-powered outboards. This discussion proved to be very useful to those trying to decide which motor would be best for them. What was missing, however, was someone who had first-hand experience with both types of motors and who could offer a direct one-to-one comparison.
I imagine some who use gasoline-powered outboards on the TI/AI might wonder what they are missing not owning a Torqeedo 403. I, as an owner of a 403, wondered what I was missing not using a gasoline-powered outboard. I was perfectly happy with just my 403 and I really didn’t want a gasoline outboard, but I just couldn’t stand not knowing what it was like to have one. So I thought and thought about it and finally decided what the heck, why not? While it may be completely unnecessary and excessive to use both, I nonetheless decided to purchase a gasoline outboard to: 1) learn once and for all which is better; 2) share this knowledge with other TI/AI owners; and 3) thoroughly enjoy the best features of both. Additionally, I’m an engineer and lifelong tinkerer who is hopelessly driven to do such crazy things. I enjoy working on my TI almost as much as sailing it.
This review is in several parts. This first will cover the comparison and selection of a gasoline motor for the TI/AI and then the task of mounting it. Finally, I'll provide my opinion of the Torqeedo 403 electric outboard vs a gasoline outboard based on my first-hand experience with both.
Update: For a thorough review of the new 3HP Torqeedo 1103AC as well as a comparison of virtually every motor option for the TI both electric and gasoline-powered, please see my new Torqeedo 403A, 403AC, 1103AC Review, Usage, & Mounting Guide and Torqeedo 1103 AC Comprehensive Review and Comparison.Gasoline Motor Selection:The first challenge was to decide which gasoline motor to purchase. Unlike electric motors, there are several to choose from. I narrowed down the choice to these models:
Suzuki Four Stroke 2.5 HP, Model DF2.5
Yamaha Four Stroke 2.5 HP, Model F2.5SMHB
Honda Four Stroke 2.3 HP, Model BF2.3
Tohatsu Four Stroke 2.5 HP, Model MFS2.5
Mercury Four Stroke 2.5 HP, Model 2.5MH
Mariner Four Stroke 2.5 HP, Model F2.5M
Nissan Four Stroke 2.5 HP, Model 2.5B
Tohatsu Four Stroke 3.5 HP, Model MFS3.5
Mercury Four Stroke 3.5 HP, Model 3.5MH
Mariner Four Stroke 3.5 HP, Model F3.5M
Nissan Four Stroke 3.5 HP, Model 3.5B
All of these models are the short shaft versions that work best on the TI/AI. Now I should mention that there are also motors available that run on propane such as the Lehr. While these may be a great choice for some boats, I simply couldn't envision having a propane tank aboard the TI or AI. I also did not consider two-stroke models because many areas worldwide are banning these motors due to pollution issues. Most of the above motors should be available around the world so this discussion is not just limited to just one area. I didn't consider any of the Chinese outboards such as the Hidea and Vector because, at least in my opinion, they are not yet up to the quality/dependability and parts availability of the listed motors. This may change soon as China manufacturers are very innovative and have the ability to produce a competitive motor if they ever decided to enter the mainstream outboard market rather than going for the low-cost market. It's interesting to note that all of the above motors are from Japanese companies that seem to have cornered the small outboard market. In fact, the Tohatsu, Mercury, Mariner, and Nissan 2.5 and 3.5 HP motors are virtually identical and are all produced by Tohatsu. I've researched each of these motors and can provide some useful information based upon the manufacturer's specifications, independent tests and reviews by boating publications, and general overall owners' consensus. Costs are approximate, they vary by country, area, and dealership. I tried to list the lowest cost by online retailers to give a general idea of what you can purchase them for. Data should be correct but accuracy is not 100% guaranteed.
Suzuki Four Stroke 2.5 HP, Model DF2.5This is a favorite of TI owners and for good reason. It is the lightest motor of the bunch at 29 lbs (13kg) which is one of the most considerable factors for use on the TI/AI. It costs about $750 USD which is lower than most and makes it a bargain in comparison. In direct comparison tests with the other motors, it is reported to be a bit louder than most with a bit more vibration, but nothing to be too concerned about. It's been reported as dependable. It has an excellent tested bollard pull of 83 pounds of thrust which makes it the second-best performer in that area.
Specs:Cost: $750 USD
Output: 2.5 HP (1.8 kW)
Displacement: 68 cc (4.1 ci)
Bore x Stroke: 48 x 38 mm (1.89 x 1.50 in)
Weight: 29 lbs (13kg)
Fuel Tank Capacity: 0.26 US gal (1.0L)
Bollard Pull Thrust: 83 lbs
Cooling: Water
CARB Emissions Rating: 3 Star
Warranty: 3 years limited
Pros:Light Weight
Dependable
Lower Cost
High Thrust
Cons:A bit louder than some of the others
A bit more vibration in comparison
Yamaha Four Stroke 2.5 HP, Model F2.5SMHBThe newly designed Yamaha looks like a really nice motor. It's a bit costly at about $880 USD. It's also heavy for a 2.5HP at 37 lbs (17 kg). It's reported to be one of the quietest motors among the others but its bollard pull was only 78 pounds of thrust which is second to the lowest.
Specs:Cost: $880 USD
Output: 2.5 HP (1.8 kW)
Displacement: 72 cc (4.4 ci)
Bore x Stroke: 54 x 31.5 mm (2.13 x 1.24 in)
Weight: 37 lbs (17 kg)
Fuel Tank Capacity: 0.24 US gal (0.9 L)
Bollard Pull Thrust: 78 lbs
Cooling: Water
CARB Emissions Rating: 3 Star
Warranty: 3 years limited
Pros:Quiet in comparison
New, more modern design
Cons:Cost
Weight
Lower thrust in comparison
Honda Four Stroke 2.3 HP, Model BF2.3The Honda is also a favorite for use with the TI probably due to its lightweight, about the same as the Suzuki at 29.5 lbs (13 kg). However, it's expensive in comparison at around $930 USD. Unlike the others, it's air-cooled which eliminates the need to maintain the impeller, but without a water jacket, it's reported to be a bit noisier than the others in a direct comparison. Also, unlike the others, it uses a centrifugal clutch rather than a gear selector to engage the prop. Some like this better, others like it less. At 2.3 HP it is the least powerful of the lot with a tested bollard pull of only 66 pounds of thrust. It has one of the longest warranties at 5 years.
Specs:Cost: $930 USD
Output: 2.3HP (1.7 kW)
Displacement: 57.2 cc (3.49 ci)
Bore x Stroke: 45 x 36 mm (1.8 x 1.4 in)
Weight: 29.5 lbs (13 kg)
Fuel Tank Capacity: 0.29 US gal (1.1 L)
Bollard Pull Thrust: 66 lbs
Cooling: Air
CARB Emissions Rating: 3 Star
Warranty: 5 years limited
Pros: Lightweight
Smaller size
Longer warranty
Cons:Cost
A bit louder than some of the others
Lowest HP/Thrust
Tohatsu Four Stroke 2.5 HP, Model MFS2.5
Mercury Four Stroke 2.5 HP, Model 2.5MH
Mariner Four Stroke 2.5 HP, Model F2.5M
Nissan Four Stroke 2.5 HP, Model 2.5BI list all of these motors together because they are virtually identical except for minor details such as cosmetics. They are all manufactured by Tohatsu of Japan and rebranded for Mercury, Mariner, and Nissan. This is a very curious motor because the 2.5 HP and 3.5HP versions appear identical in everything except the maximum RPM and HP. It has been reported that the only difference is that the 2.5HP is limited to a lower RPM and thus HP output by carburation. I cannot confirm this. Some even claim there is an easy modification to allow the 2.5HP to produce 3.5HP. In any case, other than saving a few dollars, I don't see any good reason not to buy the 3.5HP version since they are the exact same size and weight. So please skip to the 3.5HP version below for the Pros and Cons for the 3.5 HP version.
Specs:Cost: $890-$920 USD
Output: 2.5 HP (1.8 kW)
Displacement: 85.5 cc (5.2 ci)
Bore x Stroke: 55 x 36 mm (2.17 x 1.42 in)
Weight: 38lbs (17 kg)
Fuel Tank Capacity: 0.26 US gal (1 L)
Bollard Pull Thrust: NA
Cooling: Water
CARB Emissions Rating: 3 Stars
Warranty: 5 years limited (Tohatsu), 3 years limited (others)
Tohatsu Four Stroke 3.5 HP, Model MFS3.5
Mercury Four Stroke 3.5 HP, Model 3.5MH
Mariner Four Stroke 3.5 HP, Model F3.5M
Nissan Four Stroke 3.5 HP, Model 3.5BAgain, I list all of these motors together because they are virtually identical except for minor details such as cosmetics, and are all said to be designed and manufactured by Tohatsu of Japan. For some reason, some models cost a bit more than others but they are, for all intents and purposes, the same motor with the same performance. This motor is unique in that for around the same class of size and weight as a 2.5HP motor, you get a full 1 HP more of performance. This is reflected in the tested bollard pull of a very impressive 90 pounds of thrust, the best of all the motors here. The weight is the highest at 38 pounds, but if you want the additional power, it may be worth the additional 9 pounds over the lightest weight motor. Just try to lose the weight somewhere else if you think that's important. It also has one of the longest warranties at 5 years if you buy the Tohatsu version, otherwise, it's 3 years. In a direct comparison with the others, it was reported to be the smoothest with the least vibrations and one of the quietest. It's fairly expensive in comparison at $970-$1100 USD (depending on the brand) but you do get more HP for the modest extra cost. If you want to save about $100 you can get the 2.5HP version but for the same size/weight, this makes little sense to me.
Specs:Cost: $970-$1100 USD (Brand dependent)
Output: 3.5 HP (2.6 kW)
Displacement: 85.5 cc (5.2 ci)
Bore x Stroke: 55 x 36 mm (2.17 x 1.42 in)
Weight: 38lbs (17 kg)
Fuel Tank Capacity: 0.26 US gal (1.0 L)
Bollard Pull Thrust: 90 lbs
Cooling: Water
CARB Emissions Rating: 3 Stars
Warranty: 5 years limited (Tohatsu), 3 years limited (others)
Pros:Best HP/Thrust in class
Smoother/Quieter in comparison
Longer warranty (Tohatsu)
Cons:Conclusion:All of these motors are acceptable and each has its pros and cons. In my opinion, the two that stand out are the Suzuki 2.5HP and the Tohatsu (Mercury, Mariner, Nissan) 3.5HP. The Suzuki is the best for the money with the lightest weight and the second-best power. That's hard to beat. The Tohatsu (Mercury, Mariner, Nissan) 3.5HP is very tempting for the extra power and smooth operation. Too tempting for me in fact because this was the one I chose, and so far I've been very happy with it. It's a beast in power (more about that later). However, in retrospect, I feel I would have been just as happy with the Suzuki and I'm inclined to recommend that first to others for use on the TI because of the lighter weight, which is an important factor, as well as the lower cost. Of course, you'll need to decide which motor is best for your purposes.
Update: I can no longer recommend the Tohatsu, Mercury, Mariner, and Nissan 2.5HP or 3.5HP motors for the TI or AI. All of these motors share the same very serious design flaw. The motor cowl has large openings on the bottom which allow water into the motor chamber where it is then sucked into the carburetor causing the motor to repeatedly sputter and stall. These motors were designed for light-duty applications and transom mounting only such as with boat tenders. The TI/AI constitutes a heavy-duty application where the motor is subject to considerable splashing due to being side-mounted. For more information please see
this post.
Motor Mount:Mounting the Torqeedo 403 was a simple procedure and the mount is provided. In contrast, mounting a gasoline engine on the TI can be daunting, especially if you lack the skills to design a mount yourself or at least the skills to copy someone else's. You’re pretty much on your own. There are some commercial TI/AI mounts available, but these seem to be more for lightweight trolling motors than heavier gasoline motors. You have to be very careful when providing a mount because if you do something wrong you could severely damage your hull and/or your motor. You may even lose your motor in the water. You can also endanger the safety of you and your passengers.
It's my guess that Hobie probably would not cover hull damage caused by mounting a gasoline motor. Other than looking the other way, Hobie does not anywhere appear to endorse the use of any gasoline motor with the TI/AI. The TI specification for a motor is "400 Watts" maximum. A 2.5 HP motor equivalency is about 1,864 Watts or 1.86 Kilowatts, obviously far above the specification. So if your boat is currently under warranty you might want to consider this before proceeding, or stick to the Hobie Evolve electric motor or its first cousin the Torqeedo 403 which is the same motor in a different package.
There are many motor mount designs for the TI shown on this forum and in other places, ranging from ingenious to ridiculous and everything in between. What I decided to do was to take the all best features of the motor mounts others have designed and incorporate them into a simple, easy-to-fabricate, relatively low-cost design. I thank everyone who took the time to document their mount designs, they helped me a great deal in designing my own.
You can replicate this design (
at your own risk) or any of the others if you feel you have the necessary skills and equipment it takes to fabricate one. For this design, you'll only need to be able to drill some holes (best to use a drill press when needed), tap some threads (use high-quality taps, tap lubricant, and the
proper size tap drills), cut metal (aluminum cuts relatively easily by hand but a metal chop saw is best), and secure some bolts (use high-quality stainless nuts and bolts, lock washers, and Red Loctite).
An ideal motor mount should: be easy to fabricate, be very strong, properly distribute the load evenly to the hull, be highly failure resistant yet simple in design, be corrosion proof, adjustable, easily removed, and not detrimental to the design or the value of the boat's hull. By far, the best designs incorporate the use of metal. Nothing, other than exotic, expensive materials, can equal the strength-to-weight characteristics and low cost of metal. However, many metals such as untreated steel, corrode quickly in a marine environment. This leaves stainless steel, galvanized steel, and aluminum as the best choices in my opinion. I suppose you could also use ordinary carbon/mild steel and then paint or powder coat it, but that's an unnecessary extra step and may not provide as good of a corrosion resistance. Stainless steel is expensive and galvanized steel leaves untreated areas when cut. Both are quite heavy compared to aluminum. Aluminum is inexpensive, readily available, lightweight, and corrosion resistant, but not quite as strong. Still, I feel that with an adequate thickness, aluminum appears to be the best choice.
One of the primary considerations in the design is to provide a mount that will not move or rotate or unduly flex in any direction, especially in the directions where the motor is stressing the hull and mount either by its weight or by its produced thrust. The best designs, in my opinion, use square tubing. It's uncomplicated and very strong and it can provide a stable, non-flexing mount all on its own without the need for complex external bracing as seen on many custom mounts. You can easily add external backing to this design for extra support, but with the square tubing providing an excellent base, I feel it's not really necessary. Still, that decision is up to you for yours. I decided to use 2" x 2" by 1/4" thick square aluminum tubing. This is readily available online or from a local supplier in the length needed at a relatively low cost. You'll need about five feet (60 inches) of it.
It's more than strong enough for the task and if anything is a bit overkill, but better to be safe than sorry.
Other primary considerations for me were to provide adjustability and not to damage or detriment the hull if I ever decided to sell the boat without the motor. Many mounts use a custom-designed hull bracket which is only good for the specific motor mount, and some are not so great looking. If the boat was ever sold without the motor, the bracket would have to remain with the boat or else all the drilled holes in the TI's hull would need to be plugged somehow. That wouldn't please a potential buyer. So I decided to use a
YakAttack Gear Trac GT90 12 Inch Aluminum Mounting Track to provide the mount interface to the TI's hull.
This is a very strong, professionally engineered bracket that has many uses other than a motor mount and will add value to the TI rather than detract from it. To further increase its mounting strength and ease assembly, I also used the optional
YakAttack GT90 12 Inch Backing Plate.
This attaches the track to the hull so securely that you could probably lift the entire boat with it without damaging the hull. I would have liked to use the even more robust
Gear Trac GT175 bracket, but unfortunately, the TI hull section where I wanted to attach the motor was too narrow. That probably would have been overkill anyway.
The Gear Trac GT90 system optionally provides
stainless steel track nuts which slide into the track.
These probably would have worked fine but I decided to make my own out of 1/2" wide by 3/16" thick by 10-12" long stainless steel flat bar stock. This method uses the full length of the track rather than just a few inches of it for superior strength. It only required drilling and tapping two holes for 1/4-28 hex head bolts which were easy enough. I highly recommend doing it this way if you have the requisite skills and can find the materials. The more strength in the design, the better. I'm still looking for a stainless steel source for this bar, if you can't find one either then use a piece of ordinary steel for now like I had to until a piece of stainless can be found. Do
not use aluminum for this bar, it's not strong enough at this thickness for a tap for this particular purpose.
I decided to mount the motor as far in the back of the TI as was practical. The prop kicks up an impressive rooster tail of water which partially washes over the back of the boat. Placing it further back reduces the area where the water splashes the boat. This does place the throttle control a bit farther back, but it's still easily reachable and out of the way for other purposes. I also need to preserve the storage area in back of the rear seat for my two 403 motor batteries (yes, I intend to use both motors together, more on that later). So I placed the motor mount just in front of the rear hatch where I carefully allowed room for the hatch to open and close normally.
This proved to be ideal. This does shift the weight of the motor a bit further back. You'll need to decide if the combined weight of the motor, the mount, any cargo, and yourself puts the rear of the hull too deep into the water. The hull was a bit deeper than with no gas outboard, of course, but on my boat, I didn't see any issues. I weigh 175 lbs and my gas motor weighs 38 lbs. If you wish to mount the motor much closer to the rear seat then you'll need to mount the GT90 Gear Trac in front of the rod holders rather than behind them.
Once you decide where to place the mount, secure the GT90 Gear Trac approximately in the middle of this location to give you room for adjustments later if necessary.
Follow the instructions on the package to mount the Gear Trac and the backing plate to the TI/AI's hull. All the necessary hardware is included. I also recommend using
3M 5200 Fast Cure Marine Sealant/Adhesive for extra strength, flexibility, vibration dampening, and a waterproof seal.
Next, cut the aluminum tubing to the widest area of the hull you expect to use. This will be the Base Bar.
It will also raise the mounting area up 2 inches which several others have reported is necessary to allow for clearance for water to pass under the mount without causing an annoying splash back onto the rear seat occupant. Secure this base bar to the GT90 Gear Trac using four high quality 3/4" long 1/4-28 socket head stainless steel bolts (2 per side), washers, lock washers, and
Red Loctite to a 1/2" wide by 3/16" thick by 12" long stainless steel flat bar with corresponding drilled and tapped holes inserted into the GT90 Gear Trac. You
must use lock washers and Red Loctite. Any gas motor produces vibrations that will loosen bolts. Always check these bolts periodically to ensure they never become loose.
You can also use the optional threaded inserts for the GT90 Gear Trac, but these will not be as strong and I don't recommend it since maximum strength is required here. Ensure the Base Bar is very secure, properly tightened, and the bolts are not bottoming out on the Gear Trac. If they do, then use an additional washer, but the threads need to be
fully engaged for maximum strength so do
not use shorter bolts. If you do this correctly you will quickly see how strong the mount is. If you wish, you may use additional external bracing here to make the mount even stronger and more fail-resistant. Simply cut a short section of the aluminum square tubing for each side and secure both to the Gear Trac bar and the Base Bar.
Next cut a section of the aluminum bar to extend from the port side of the base bar to as far as you want the motor mount to extend over the starboard side of the hull. This will be the Middle Bar.
I recommend at least 10 inches of overhang to begin with. If you mount the motor too close to the side of the hull, the rooster tail of water from the prop will splash excessively over the back of the boat. If you mount it too far out, the weight of the motor will further offset the hull’s side-to-side weight distribution. The trick is to find the sweet spot. I'm still experimenting with this. It's best to leave more than you need now and perhaps cut it back later once you find the ideal location for your specific motor. Mount this middle bar to the base bar using 2 1/2 inch 5/16-18 stainless steel hex head bolts, nuts, lock washers, and Red Loctite. You can use two to four bolts. I used three, one on each side and one in the middle. For the middle bolt, tap a 5/16-18 thread into the base bar since you can't get a nut in there (unless you want to drill a hole completely through the Base Bar and use a longer bolt).
Finally, cut a section of the aluminum bar to extend from the starboard side end of the base bar to the starboard overhang end of the middle bar. This is the Upper Bar.
Secure it to the middle bar using four 1-inch long 1/4-28 socket head stainless steel bolts (2 per side as shown). Note: I had to use a piece of galvanized steel tubing here because I didn’t order enough aluminum tubing, but you should have enough if you ordered 5 feet.
You'll need to tap some threads into the middle bar on the inside end, but you can use nuts on the outside end. Use lock washers and Red Loctite to secure the bolts.
This upper bar provides both a 4 x 10-inch "transom" to mount the motor and places the motor prop at the proper level below the hull for most 15" short shaft motors. If you must use a long shaft motor, simply add additional tubing to the top until you reach the proper prop position. The prop must be several inches into the water below the hull, and the cooling water intake must be underwater. Consult your motor's operation manual for details and adjust the height if necessary by using longer or shorter height tubing for the upper bar.
I then covered the "transom" area with rubber and temporarily held it in place with gorilla tape. I'll improve this later by gluing the rubber in place using the 3M 5200 adhesive. The rubber is optional and provides a little more vibration dampening.
Mount the motor adjusting the location as needed. Be certain the transom screws are very tight and check often. It's also a good idea on any mount or boat to secure a catch rope or cable to the motor in case it ever becomes loose.
Now try moving the motor in all directions. If you made the mount correctly you should see no undue movement or flexing other than some minor flexing of the TI's polyethylene hull itself which is unavoidable in any design. That's it, the motor mount is now complete! Go out and carefully test it with your motor.
The aluminum is corrosion resistant all on its own but I plan to powder coat the entire mount in black off-season for a better look and improved corrosion resistance.
Always check all the bolts and the mount's integrity before you use the motor. If you ever see any issue, fix it before you use the motor again.
The TI's hull is of high quality but was not specifically designed to hold a gasoline motor. As time goes by, ensure the motor's weight and thrust stresses are not causing any issues anywhere. The motor is only the weight of a small child and the mount is securely attached so it shouldn't harm the hull, but you just never know. Use any motor and mount at your own risk. I also highly recommend propping the bottom of the motor up whenever it's not in use on season so the weight of the motor doesn't slowly warp the hull over time. Do not store the motor on the boat off-season.
Some people have made a splash guard to reduce the water which splashes on the back of the boat. This is a good idea and next on my list. This is an issue with all mounts, but if your rear hatch is watertight it really causes no major problems as the water quickly drains out of the rear cargo area drain holes.
Direct Comparison of the Torqeedo 403 Electric Outboard vs Gasoline Outboards After using my new gasoline outboard for the entire season thus far, I feel I now have an excellent basis to compare it directly and objectively with my Torqeedo 403 Electric Outboard which I've owned for one and a half seasons now. I believe I'm probably currently the only person here who has both mounted on their TI at the same time, so this gives me a rare point of view allowing me to discuss both motors practically and empirically rather than theoretically which has been a significant problem for comparisons with the 403. As I've said many times, there is more misinformation posted about the 403 than information because many try to evaluate it without ever owning or even ever trying it, and this, in turn, leads to a great deal of misinformation about it as people try to guess how it will perform based only upon speculation.
We all have our biases but I will strive to be as objective as possible and truthfully discuss the pros and cons of each motor type. Be advised that there will be no clear "winner" here because both motors are better at specific things and your choice will depend entirely on your intended use and which features are most important to you.
Mounting:If you read the section on mounting the gas outboard above and the section on mounting the Torqeedo in my
403 review you can readily see that the 403 is much easier to mount. It's also far easier on the TI/AI's hull because it does not place the same weight or thrust stresses on the hull as does a gas outboard. It's highly unlikely that mounting the 403 to the TI/AI would ever void your warranty, but it's likely that mounting a gas outboard would if there was a resulting hull damage issue. Clearly, the 403 has the advantage here.
Weight:The 403 weighs a total of 19.6 pounds (8.9 kg). This includes the battery and the mount. You hardly even notice it's there. The weight of the lightest outboard is 29 lbs (13 kg) dry and this does not include the weight of the fuel or the mount. Gasoline weighs 6.3 lbs per gallon and the motor mount will add another several pounds. Gas motors are also far more bulky and cumbersome. Clearly, 403 has the advantage here and there is little more to discuss. However, weight is not a huge issue and unless your TI/AI is already overloaded I don't see a huge advantage in a lighter-weight motor. But if this is a consideration for you, then the 403 has the advantage.
Range:You'd think the advantage here clearly goes to the gas outboard, and it probably does, but there is a lot to consider before coming to a comprehensive conclusion. The gas tanks on these outboards are tiny, typically about a quart/liter or so. That will typically power the outboard for around an hour, give or take, at a decent cruising speed of about 5-6 mph. So the range of an outboard on a tank of gas is around 5-6 miles. Sure, you can do better at lower speeds, but I find that 5-6 miles per hour is how fast I typically go with my outboard. If you want to go further you have to come up with a way to store more gas on board since these engines generally cannot be modified to use a bigger, external gas tank. I use a
30 oz MSR fuel bottle which is a little less than another tank's worth.
I carry four of them with me. This, along with a full tank of gas to begin with, gives me a typical range of about 25-30 miles. That's great, but that's also about equal to the range of my 403's two batteries at about 3-5 mph so it's not a night and day difference.
Additionally, I really dislike having to fill the MSR bottles with gas every time I go out. I never like to handle gas. It's time-consuming, annoying, and a bit difficult to fill those little bottles without spilling. It's also a bit dangerous to have gasoline aboard a plastic boat. If a fire ever broke out it could cause the hull to melt or possibly catch fire, so I also now have to carry a fire extinguisher onboard. Filling the motor's tank every hour while onboard a bobbing boat is a real hoot. Even with a funnel I spill gas. Contrast that to the 403 which will go many hours on a single battery. If you need to change batteries it's a safe, quick, and easy operation taking less than a minute or so. When you get back, charging the batteries is a breeze. You simply plug it into the charger and forget about it until the next day or whenever you need it again.
Still, I give the range award to the outboard because it is only limited by how much gas you carry and not on very expensive lithium batteries. But the convenience award and a close second on range goes to the 403.
Speed:There's no question that the speed category goes to the gas outboard, hands down. My Tohatsu 3.5 HP will power the TI at 3.5 mph at little more than idle, about an eighth throttle. At a third throttle, I'm cruising at 5-6 mph. At half throttle, I'm going about 7 mph. It's a beast for power, the boat actually gets up on plane. At three-quarter's throttle, I hit about 8 MPH but I can't go much faster at full throttle because I believe I'm hitting the rev limiter. I may need to re-prop to find the maximum speed, but I'm more than satisfied with what I've already got. The Torqeedo will go for many hours at 3-4 mph but if you push it over 4 mph you use disproportionately more battery power so you have to save that for when you need it. This is easily accomplished with the onboard range computer and is not at all a problem, but consistently higher speed is not the 403's forte unless you want to resolve the issue with more expensive batteries. The maximum I ever got the 403 to go was 6.3 mph, but that was in perfect condition and not practical. So if you're looking for maximum speed, a gas outboard is for you. However, that said, I've often commented that if you're looking to get somewhere fast on the water then the TI is most definitely not for you. Let's face it, whether you're going 3-5 mph or 5-7 mph, you're still going very slow, even a kid’s bicycle can travel far faster. My 215 HP turbo-charged jet boat used to go 60 mph, so the TI is a snail whether you own an electric or gas outboard, make no mistake about that. No one reading this post should be focused on speed because you own the wrong boat for that.
Thrust:Thrust is required to generate speed but it's also necessary to overcome strong headwinds, currents, heavy waves, etc. So I'm covering this separately from speed. The 403 has only 33 pounds of thrust which is considerably lower than the lowest thrust generated by the gas motors covered here. The 403 is roughly equivalent to a 1.5 HP gas motor. If I were in very bad conditions where maximum continuous thrust was needed to get me out of trouble, then I would prefer a gasoline motor. That said, my 403 has never failed me when I was in bad conditions. It has enough thrust to power you out of all but the worst-case scenarios. Still, if you're using your TI offshore or in areas where very bad conditions can happen often, then you should consider a gas outboard over the 403. Torqeedo does, however, manufacture considerably more powerful electric motors than the 403 if you were resolved to go electric. This category clearly goes to gas outboards.
Controls:All of these gas outboards use the typical stick-mounted throttle control which works well enough. I know of no one who has installed a remote throttle for one. I don't think a remote throttle kit is even available for any of them in this HP range. In the TI you have to a bit awkwardly reach for the throttle control on the gas outboards. This is fine though, I have no real complaints. However, by contrast, the remote throttle of the 403 is wonderful. You can place it anywhere you want so it’s always at your fingertips. There is no setting a choke, pulling a rope, fussing with the choke/throttle until the engine warms up, or engaging/disengaging a gear lever. Press one button and the 403 is on for the entire day. Push the throttle lever forward and the motor springs to life, pull it back to neutral and the motor stops. Pull the lever back and it quickly goes into reverse. To make these gas motors go into "reverse" you have to spin them around 180 degrees and flip the throttle stick upside down, there is no reverse gear on any of them. What a laugh. The 403's throttle control also includes an incredible GPS-controlled range computer, a battery power remaining readout, and your speed in knots, kph, or mph. Who could ask for more? The 403 is the clear leader in this category.
Tilt:You need to tilt both the 403 and the gas motors anytime you beach the TI, at the boat ramp, and in very shallow or hazard-laden water, or else you can do considerable damage to the prop or pylon. To tilt or lower the 403 you simply pull on a rope. It's quick and easy. To tilt or lower the gas motor you need to reach out and grab the motor. It's a bit harder but not difficult unless you have a physical disability or injury such as an arm or back condition. So this category goes to the 403, but unless you have an impairment it's not a big deal.
Reliability:In all the time I've owned it the 403 has never let me down for more than a minute or so. I occasionally got a rare tilt error, but I had that fixed off-season. It was always easy to fix on the water by shaking it a bit with the up/down controls so it was never a real issue. There's not a lot to go wrong with an electric motor and the 403 is very well-made and very well-protected. By contrast, I had issues with my brand-new Tohatsu right away. One day it just died on the water after working perfectly for several hours. I could not get it running again reliably for the rest of the day. Thank goodness I still had the 403 because I was about 15 miles from the boat ramp which was upwind and it was late. I still don't know what went wrong, maybe I got some water in the tank when I refilled it on the water, it was very choppy that day. Maybe a tiny piece of contamination got into the gas even though I ran it through a filter first. I drained the tank and the fuel bowl when I got home and it's been running fine since then, but it did let me down when I needed it.
It should be noted that all of these gasoline motors have tiny carburetors with tiny orifices and can be very sensitive to both dirty and/or water-laden fuel and related issues caused by ethanol in gasoline which is widely prevalent in many areas. Most can handle only up to 10% added ethanol. Since ethanol is hydrophilic (attracts water) and water is obviously present in a marine environment, care should be taken to ensure the fuel remains stable. Most manufacturers advise the use of a marine gas stabilizer such Sta-Bil Marine or Starbrite fuel treatment. Also recommended is the use of a water-separating fuel filter. Since these motors are so tiny and have integrated fuel tanks, this is all but impossible. However, you can use a funnel based water separating fuel filter such as the
Mr. Funnel AF3CB Fuel Filter to filter out both water and contaminants before pouring it into the motor's tank.
The point is that there is a lot more to go wrong with a tiny, carbureted gas motor than with an electric motor. I have to give the reliability category to the 403.
Technology:The 403 is about as high-tech an accessory as you can buy for the TI. The highly advanced motor design, state-of-the-art lithium batteries, and GPS / computer-enabled controls all make for a very impressive package. Gasoline motor manufacturers try to sell you on the updates they make to their bottom-of-the-line outboards, but even the newly designed Yamaha is using base technology that was around in 1985 when I first started boating. Today's small outboards have a few decent improvements but they're overall about the same as they've been for years. Bigger outboards have all the best features such as computer controls and fuel injection, but the micro outboards get none of that. In fact, if anything the new emissions standards and ethanol in gasoline make them even more finicky than before. The tiny carburetors can be especially troublesome if not meticulously maintained. So the clear winner here is the 403. When electric motors and their batteries reach the critical point where they approach the power and range of gasoline motors, many, including myself, predict the ultimate demise of most gasoline motors. This may occur in the next decade or so.
Noise:Well, this is a no-brainer, the 403 is quieter than any of these outboards by far. My Tohatsu was rated as one of the "quietest" gas outboards, but it's anything but quiet. I can deal with the noise, it's not intolerable, but after several hours it can give me a headache, and I don't think it's very good for my aging hearing. I'll probably start wearing earplugs or perhaps some noise-suppressing earphones. You've all heard gasoline outboards at close range, I don't need to be any more descriptive. The 403 is not entirely silent by any means either, it makes a whirring sound which a few may find slightly grating. It doesn't bother me at all, sometimes I forget about it entirely. It's quieter than a typical voice conversation. Other people in boats a few meters away seem to never hear it. I sometimes startle them when I appear seemingly out of nowhere. The only thing quieter is running by pedal or the wind.
Pollution:The newer four-stroke gasoline outboards are much better than in the past, especially when compared to two-stroke engines. All of these here have a 3 three-star CARB rating which means they have "Ultra Low" emissions. I can still smell the exhaust a bit, however, and I really hate gasoline fumes which I now have on board more than I like. These probably come more from me spilling a bit of gas when refueling on choppy water rather than through any fault of the motor's fuel system. The 403, on the other hand, has zero pollution of any sort.
Maintenance:All gasoline outboards require periodic maintenance. Care must be taken to always ensure the fuel system remains clean and trouble-free. The engine and gear oil should be changed at least once a year. The spark plug should be changed at the recommended interval. The water impeller needs to be replaced periodically. If you’re operating in saltwater, care should be taken to flush the motor out after each use. Water-cooled motors need to be flushed and winterized. The 403 requires no periodic maintenance other than to keep it reasonably clean and check the fittings now and then. The 403 is best in this category.
Safety:I covered this a bit above. Any gasoline motor introduces a highly flammable fuel on board. Polyethylene has a relatively low melting point, you never want to expose it to fire. If even a small fire broke out, the boat might begin to melt near the fire or start to smolder or burn. Keep a fire extinguisher onboard in an easily accessible spot. The 403 requires no volatile fuel but there is a lot of energy stored in those lithium batteries. Lithium batteries have been known to self-ignite and burn furiously. Torqeedo batteries are very well made and employ significant internal protections. It's highly unlikely one would ever self-ignite but stranger things have happened. In any case, these batteries are considerably safer than gasoline.
Outboard motors have more thrust than the 403, so in a worst-case scenario where you are up against very rough seas, the gasoline motor is more likely to get you safely back to shore. But the 403 is no slouch either, it can handle all but the worst conditions, and it is certainly better than no motor at all. I, personally would never venture out in rough weather or offshore in a TI without a motor. I had my TI one season without a motor and I got into a few scary situations. Any motor makes the TI much safer in bad seas.
Each motor can provide a backup to the rudder should it fail. The 403 steers the boat quite nicely on its own, almost as well as the rudder. However, it still relies on the rudder lines working. My gasoline motor does not steer the boat nearly as well but does not rely on any part of the TI's rudder system to be working.
All considered I would say this category is a tie.
Cost:The Torqeedo 403 is very expensive. It currently sells for $1,529 USD which is the lowest price I could find. Used ones for less are very rare. Worse, a spare battery, necessary for longer range, adds another $525 to $787 USD. This is beyond a reasonable total cost for many. In contrast, you can get the excellent Suzuki 2.5HP motor for only about $750 USD. Material for a mount costs about another $150 or so, and, at least in the US, gasoline to power the motor is currently quite reasonable. So, without question, gasoline outboards win this category hands down. Hopefully, the price of high-quality electric marine outboards will come down if more competition becomes available, but that may be a while. For now, if cost is a major consideration for you, outboards are a bargain compared to the 403.
Conclusion:Owning and operating an electric and gasoline motor on my TI has given me a real appreciation of the merits of both. The gasoline motor can’t be beaten when it comes to thrust and speed, it simply has more power available than the 403. However, this extra power comes at a price in weight, noise, fuel safety, mounting, reliability, and maintenance where the 403 excels. Range is a toss-up, both motors are close with a slight edge going to the gas outboard because the 403 requires extra, expensive batteries to match the range of an outboard with a practical amount of gasoline on board.
I now have the luxury of owning both. In my opinion, this is the best but the most costly option. When I want to go faster, I fire up the outboard. When I want to relax and cruise quietly, I use the 403. My range is now vast with both motors, I can travel as far as I want. If one motor should fail, I have the other to back it up. I can venture out knowing that if the conditions turn bad I have two motors to get me back to shore. I really like both of these motors and each is outstanding in its own way.
But of course, not many of you will ever choose to use both, so the question I assume you want to know is if I could have only one, which would I choose? For me, the answer is the 403. It does almost everything the gasoline outboard can do with a lot less overhead and bother. It’s not as fast or as powerful, but that small extra speed and power is really not needed on a TI. Seriously, does it really matter that much if you travel 3-5 mph rather than 5-7 mph? Sometimes I
think I’m going fast with my gas outboard until even a small powerboat blows by me like I was standing still. Slow is slow, a couple of extra mph doesn’t really help much. I certainly didn’t buy the TI for speed anyway, I bought it to sail. Having a motor on it is mostly for the times I can’t sail because there isn’t enough wind, or the wind is blowing in the wrong direction, or for safety if conditions turn bad. But the 403 doesn't come cheap, if you really want one be prepared to spend over twice as much as a gasoline motor, especially if you need an extra battery for more range. Yet you've probably already spent $6K or more for your TI to buy one of the best (and most expensive) production kayaks ever made, so you may be tolerant of such costs. People spend far, far more on most sail and powerboats. Even with the 403, boating with the TI is actually quite reasonable financially in comparison.
This is only my opinion, and others will disagree. If you want a motor on your TI/AI decide which motor is best for
you depending upon
your specific requirements. You now have a lot more information to help you decide. Both motor options are great and a -lot- better than not having any motor. You really can’t go wrong choosing one or the other and afterward, you’ll wonder why you didn’t install a motor sooner. You’ll never leave shore without one again.