After researching owner feedback, manufacturer specifications, and industry standards, we evaluated the most popular 4 stroke outboard motors available. Our comparison focuses on reliability, fuel efficiency, and real-world performance for various boat types. Below are our top picks with honest assessments of their strengths and limitations.
| Photo | Product | Score | Buy |
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Suzuki DF115A Best Overall 115 HP, 4-cylinder, 2.0L, 353 lbs |
9.2 | 🛒 Check Price |
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Yamaha F115 Runner Up 115 HP, 4-cylinder, 1.8L, 377 lbs |
9.0 | 🛒 Check Price |
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Mercury 115 EFI Best Value 115 HP, 4-cylinder, 2.1L, 395 lbs |
8.7 | 🛒 Check Price |
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Honda BF115 Quietest Operation 115 HP, 4-cylinder, 2.2L, 403 lbs |
8.4 | 🛒 Check Price |
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Tohatsu MFS115 Lightest in Class 115 HP, 4-cylinder, 2.0L, 353 lbs |
8.1 | 🛒 Check Price |
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Suzuki DF140A Best for Power 140 HP, 4-cylinder, 2.0L, 397 lbs |
7.8 | 🛒 Check Price |
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Yamaha F90 Best for Small Boats 90 HP, 4-cylinder, 1.8L, 353 lbs |
7.3 | 🛒 Check Price |
1. Suzuki DF115A: Best Overall
The Suzuki DF115A stands out in our evaluation for its refined engineering and outstanding fuel economy. Based on owner feedback and the spec sheets, its lean burn technology delivers consistent savings over time, making it a top choice for frequent boaters. The motor starts reliably and runs smoothly across the power band, with minimal vibration. Its compact size also simplifies installation on a wide range of boats, from center consoles to aluminum fishing rigs.
However, we found that the DF115A is not the lightest in its class, which could be a factor for smaller boats with strict weight limits. Additionally, some owners report that parts and service can be less accessible in remote areas compared to market leaders like Mercury or Yamaha. If you prioritize fuel efficiency and smooth operation over brute power, this motor is an excellent choice. But if you need maximum top-end speed or have a heavy boat, consider a higher-horsepower model.
- Lean burn technology improves fuel economy by up to 10% over competitors
- Dual overhead camshafts for smooth power delivery
- Compact and lightweight design for its power class
Pros: Excellent fuel efficiency; Smooth and quiet operation; Strong mid-range torque
Cons: Higher initial investment than some 2-stroke alternatives
2. Yamaha F115: Runner Up
The Yamaha F115 is a benchmark in the 115 HP category, praised by owners for its durability and ease of maintenance. In our evaluation, its robust construction and extensive dealer network make it a safe bet for boaters who value peace of mind. The motor delivers consistent power and idles smoothly, thanks to its advanced fuel injection system. Many users report trouble-free operation for years with routine service.
On the downside, the F115 is one of the heavier 115 HP motors, which can affect boat balance and fuel economy on lighter hulls. It also tends to be priced at a premium, though the long-term value often justifies the cost. If you prioritize reliability and dealer support above all else, this motor is a strong choice. However, if weight is a critical factor or you want the latest fuel-saving technology, consider the Suzuki DF115A or the Mercury 115 EFI.
- Proven reliability with extensive dealer network
- Shift Dampener System for smooth gear engagement
- Multi-point electronic fuel injection for quick starts
Pros: Exceptional reliability track record; Widespread service availability; Smooth shifting
Cons: Heavier than some competitors in its class
3. Mercury 115 EFI: Best Value
The Mercury 115 EFI offers a compelling balance of performance and price, making it our pick for best value. Based on owner feedback, it provides strong acceleration and a solid hole shot, especially with the optional Command Thrust gearcase. The EFI system ensures reliable starting and smooth operation across the RPM range. Many budget-conscious boaters find this motor delivers everything they need without breaking the bank.
However, we noted that the Mercury 115 EFI is among the heavier motors in its class, which may be a drawback for smaller boats. Some users also mention that it runs slightly louder at idle compared to Yamaha or Suzuki models. If you are looking for a cost-effective motor that still performs well and you don’t mind a bit more weight and noise, this is a great option. But if you prioritize quiet operation or ultra-light weight, you might prefer the Suzuki DF115A or the Tohatsu MFS115.
- Affordable price point with strong performance
- Electronic fuel injection for efficient fuel use
- Command Thrust gearcase for better hole shot
Pros: Great value for the power; Strong acceleration; Reliable EFI system
Cons: Heavier than some rivals; Can be louder at idle
4. Honda BF115: Quietest Operation
The Honda BF115 is renowned for its whisper-quiet operation and refined performance. In our evaluation, its noise reduction features make it ideal for fishermen who need a stealthy motor or anyone who values a peaceful boating experience. The motor runs exceptionally smoothly, with minimal vibration. Honda’s lean burn system also provides excellent fuel efficiency at cruising speeds, as confirmed by many owners.
That said, the BF115 is one of the heaviest and most expensive motors in this comparison. Its size can make installation challenging on smaller boats, and the higher cost may not be justified for those on a tight budget. Additionally, some owners report that parts and service can be pricier than for other brands. If quiet operation and long-term durability are your top priorities and you have the budget, the Honda BF115 is a superb choice. But if you need a lighter or more affordable motor, consider the Mercury 115 EFI or the Tohatsu MFS115.
- Advanced noise reduction technology
- Lean burn plus system for fuel efficiency
- Dual overhead camshafts and VTEC for power
Pros: Extremely quiet and smooth; Excellent fuel economy at cruise; Long engine life
Cons: Heavy and bulky; Premium price
5. Tohatsu MFS115: Lightest in Class
The Tohatsu MFS115 is a standout for its impressive weight savings, making it a favorite for boaters with weight-sensitive hulls. Based on owner feedback, it delivers reliable performance and good fuel economy, with an EFI system that starts easily. Its compact size also simplifies installation on smaller boats like skiffs and light aluminum craft. For the price, it offers solid value.
However, we found that the MFS115 lacks some of the refinement of the Yamaha or Suzuki motors, with slightly more vibration and noise at certain RPMs. Dealer support is also less extensive, which could be an issue if you need service in remote areas. If you need a lightweight motor and are willing to trade a bit of refinement for weight savings and value, this is a strong option. But if you prioritize smoothness or have a larger boat, consider the Suzuki DF115A or Yamaha F115.
- Lightest 115 HP four stroke at 353 lbs
- Electronic fuel injection for reliability
- Compact design fits smaller boats
Pros: Very lightweight; Good value; Compact footprint
Cons: Less dealer support in some regions; Not as refined as top competitors
6. Suzuki DF140A: Best for Power
The Suzuki DF140A offers a significant power bump over the 115 HP class, making it a great choice for larger boats or those needing extra grunt. In our evaluation, it maintains the same lean burn efficiency and smooth operation as the DF115A, but with more top-end speed and torque. Owners often praise its ability to plane heavier loads quickly.
However, the DF140A is heavier and pricier than many 115 HP motors, and its extra power may be unnecessary for lighter boats. Some users also note that parts can be harder to find than for Yamaha or Mercury. If you need the extra horsepower for a heavy boat or want to maximize speed, this motor is worth considering. But if your boat is light or you are on a budget, a 115 HP model like the Mercury 115 EFI would be more practical.
- Higher horsepower for heavier boats
- Lean burn technology for efficiency
- Dual overhead camshafts
Pros: Strong power output; Good fuel economy for its class; Smooth operation
Cons: Heavier and more expensive than 115 HP models; May be overkill for smaller boats
7. Yamaha F90: Best for Small Boats
The Yamaha F90 is a solid choice for smaller boats like aluminum fishing rigs or lightweight runabouts. Based on owner feedback, it offers the same reliability as its larger siblings in a more manageable package. The motor runs quietly and sips fuel, making it economical for day trips. Its weight is also reasonable for manual tilting on smaller transoms.
However, the F90 may struggle with heavier loads or larger boats, and some owners wish they had opted for more horsepower. It is also not as feature-rich as newer models, lacking some of the advanced fuel management found on the Suzuki DF115A. If you have a small boat and prioritize reliability and efficiency, the Yamaha F90 is a fine choice. But if you need more power or want the latest technology, consider stepping up to a 115 HP motor.
- Lighter weight suitable for small boats
- Proven Yamaha reliability
- Multi-point EFI for smooth running
Pros: Reliable and durable; Good power-to-weight ratio; Quiet operation
Cons: Less power for larger boats; Can be underpowered for heavy loads
Frequently Asked Questions
What is the difference between a 2-stroke and a 4-stroke boat motor?
4-stroke motors are generally more fuel-efficient, quieter, and produce fewer emissions than 2-stroke motors. They also tend to have a longer lifespan and require less frequent maintenance. However, 2-stroke motors are typically lighter and less expensive upfront. For most recreational boaters, a 4-stroke is the better choice for overall value and environmental impact.
How do I choose the right horsepower for my boat?
Horsepower selection depends on boat size, weight, and intended use. A general rule is to have at least 1 HP per 25-30 lbs of boat weight for planing hulls. Check your boat’s maximum HP rating on the capacity plate. For smaller boats (under 16 feet), 50-90 HP is common; for mid-size boats (16-20 feet), 90-150 HP is typical. Overpowering can be unsafe and void warranties.
Are 4-stroke outboards more reliable than 2-strokes?
Yes, modern 4-stroke outboards are generally more reliable due to cleaner combustion, less wear on internal parts, and better lubrication systems. They also do not require mixing oil with fuel. However, they have more moving parts and can be more complex to repair. With proper maintenance, a 4-stroke can last 1,500-2,000 hours or more.
What maintenance does a 4-stroke boat motor require?
Regular maintenance includes changing engine oil and filter every 100 hours or annually, replacing spark plugs, checking and replacing fuel filters, inspecting the water pump impeller, and flushing the cooling system with fresh water after saltwater use. It is also important to lubricate linkages and check the gearcase oil. Refer to your owner’s manual for specific intervals.
Can I use a 4-stroke outboard in saltwater?
Yes, most 4-stroke outboards are designed for saltwater use, but they require extra care. Rinse the motor with fresh water after each use, flush the cooling system, and apply anti-corrosion spray to exposed metal parts. Many motors have a saltwater-specific anode kit. Regular maintenance is critical to prevent corrosion and extend the motor’s life.
Our Verdict
After careful evaluation, the Suzuki DF115A takes the top spot for its outstanding fuel efficiency, smooth performance, and lightweight design. The Yamaha F115 is a close runner-up, offering unmatched reliability and dealer support. For budget-conscious buyers, the Mercury 115 EFI provides excellent value without sacrificing performance.
