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gas outboard motors comparison, in stock
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How much power your boat needs
The right horsepower depends on total weight (hull, motor, fuel, people and gear) and whether you want to plane or just displace. An oversized motor costs more, weighs more and often exceeds the maximum horsepower shown on the boat's capacity plate. An undersized one runs flat out all the time and wears out sooner.
| Boat | Typical horsepower | Typical use |
|---|---|---|
| Dinghy or inflatable, 7-8 ft | 2-3.5 hp | Anchorage to shore |
| Inflatable, 8-11 ft | 3.5-6 hp | Cruising and swimming; planes with a light load |
| RIB or rigid inflatable, 11-13 ft | 6-15 hp | Coastal use and snorkeling |
| Fishing skiff, 13-16 ft | 9.9-20 hp | Fishing and planing with a load |
| Sailboat 23-30 ft, auxiliary power | 6-9.9 hp (long shaft) | Maneuvering and harbor entry |
These are guidelines. Before you decide, read the maximum horsepower on your boat's capacity plate and do not exceed it.
Two-stroke or four-stroke
Four-stroke
The most common choice today. It burns less fuel, is quieter and smokes less, and you do not have to mix oil into the gas. In return it is a bit heavier and you have to check the crankcase oil. For frequent use and longer trips it is the best option.
Two-stroke
Lighter and simpler, with good response, but it uses more fuel and pollutes more. In small sizes it is still handy if you carry the motor often, as long as you use the exact mix the manufacturer specifies. If you buy one, check the right outboard oil first.
Tip: if you will be lifting the motor into a car or onto a sailboat, weight matters more than horsepower. A 30-40 lb motor is manageable; a 65 lb one is a chore.
Shaft, starting and details that matter
- Short or long shaft: short (about 15-17 in) suits inflatables and low boats; long (20-23 in) suits sailboats and boats with a high transom. If the shaft does not reach the water, the prop ventilates.
- Manual or electric start: manual is lighter and dependable; electric is convenient from mid-size power up but adds a battery and weight.
- Built-in or external tank: on small motors, a built-in tank makes carrying easy; an external one gives more range. See our fuel tanks.
- Steering: tiller on small boats, remote controls on bigger power.
- Charging coil: useful if you run a battery for lights or electronics.
Basic maintenance for a long life
- Flush the cooling system with fresh water after every saltwater trip.
- Change the engine oil and lower-unit oil on the schedule in the manual.
- Replace the water pump impeller every season or 100 hours, whichever comes first.
- Check the fuel filter, the spark plug and the condition of the hoses.
- Use fresh gas. If it will sit, drain the carburetor or add a stabilizer.
- Inspect the lower-unit anodes and replace them when they are eaten away.
The full routine is in our guide to outboard maintenance. If it ever refuses to start, begin with the checklist on why an outboard will not start.
Warning: never run the motor out of the water without a flushing attachment. Without cooling, the impeller burns up in seconds.
Break-in, fuel and transport
New motors usually call for a break-in period during the first hours: avoid holding full throttle and follow the manual. Always use fresh gas with the octane the manufacturer specifies. Too much ethanol slowly degrades hoses and seals, so check what your motor tolerates.
When you transport it, keep it in the position the manual shows (usually upright or resting on the correct side) so oil does not run into the cylinders and fuel does not leak. Also carry a few basic outboard tools, a spare spark plug and an emergency starter cord. They are cheap and can save you a long row back to the dock.
Common mistakes when buying
- Choosing by horsepower alone and not by total weight or the maximum rating of the boat.
- Buying a short shaft for a tall transom, or the other way around.
- Forgetting that a four-stroke should not be tilted or stored in just any position. Follow the manufacturer's instructions.
- Ignoring parts and service. Pick a brand with parts available near you.
- Skipping your state's rules on registration and boating education for the power you plan to install.
Frequently asked questions
What horsepower do I need for a 10-foot inflatable?
For an inflatable of about 10 feet, most owners choose 3.5 to 6 hp for relaxed cruising, or 6 to 9.9 hp if they want to plane with two or three people. Always check the maximum horsepower on the boat's capacity plate.
Is a 2-stroke or 4-stroke outboard better?
A 4-stroke burns less fuel, is quieter and does not need oil mixed into the gas, which is why it is the common choice. A 2-stroke is lighter and simpler but uses more fuel and pollutes more.
What is the difference between a short and long shaft?
It is the distance from the transom to the anti-ventilation plate of the motor. Short (about 15-17 in) for inflatables and low boats, long (20-23 in) for sailboats and boats with a high transom.
How often should a gas outboard be serviced?
Once a season or every 100 hours: oil, fuel filter, spark plug, impeller and anodes. After each saltwater trip, flush it with fresh water.
