The 2017 Mercury 115 Four Stroke: An Expert’s Deep Dive on Performance, Reliability & Value
Choosing the right outboard is one of the most critical decisions for your boat’s performance and your long-term satisfaction on the water. Get it wrong, and you’re faced with frustrating reliability issues, poor fuel economy, and a compromised boating experience. Get it right, and you unlock years of effortless, enjoyable time on the water.
So, where does the 2017 Mercury 115hp Four Stroke stand today? The 2017 Mercury 115hp Four Stroke is a mid-range outboard engine renowned for its exceptional fuel efficiency, smooth and quiet operation, and Mercury’s legendary reliability. It’s an ideal powerplant for a wide range of boats from 17 to 21 feet.
This definitive guide will provide an in-depth review, performance analysis, common issues to watch for, and expert advice to help you decide if the 2017 115hp is the right engine for you.
Understanding the 2017 Mercury 115 Four Stroke: Core Specifications
Before we dive into real-world performance, it’s crucial to understand what makes this engine tick. The 2017 model is part of a well-established and refined lineage, representing a mature and proven design.
Engine Architecture & Key Features
The 2017 Mercury 115 is a 2.1-liter, in-line four-cylinder engine. This larger displacement is a key differentiator, as it allows the engine to produce its power more effortlessly, leading to better low-end torque and overall smoothness compared to smaller-displacement competitors.
- Displacement: 2.1 L (2,130 cc)
- Cylinder Configuration: In-line 4
- Fuel System: Electronic Fuel Injection (EFI) for precise fuel delivery and easy cold starts.
- Alternator Output: A robust 60-amp output is standard, which is more than sufficient for powering electronics, live wells, and other accessories without draining the battery.
Key technologies that enhance the user experience include:
* Advanced MidSection (AMS): This proprietary Mercury system is engineered to isolate and dampen engine vibration before it transfers to the boat. The result is a noticeably smoother and quieter ride.
* PowerTrim: The integrated hydraulic PowerTrim provides 4 degrees of negative trim and 16 degrees of positive trim, allowing you to fine-tune the boat’s running attitude for optimal performance and efficiency.
* Corrosion Protection: The engine features a multi-step anti-corrosion process, including a permadry™ powertrain coating and stainless-steel components in critical areas, to ensure longevity in saltwater environments.
Official Performance & Efficiency Metrics
Mercury is known for providing transparent performance data. Here’s a snapshot of the official fuel consumption for the 2017 115hp Four Stroke, which highlights its exceptional efficiency:
| RPM | MPH (approx.) | GPH (Gallons Per Hour) | MPG (Miles Per Gallon) |
|---|---|---|---|
| 1000 | 5.0 | 0.5 | 10.0 |
| 3500 | 22.0 | 3.5 | 6.3 |
| 4500 | 32.0 | 5.8 | 5.5 |
| 6000 (WOT) | 42.0 | 9.8 | 4.3 |
Note: These figures are estimates based on a typical 18-foot center console. Actual performance will vary based on boat type, load, and conditions.
- Weight: The standard 20-inch shaft model weighs approximately 377 lbs (171 kg), striking a good balance between power and weight.
- Shaft Lengths: Available in 20″, 25″, and 30″ shaft lengths to properly fit a wide variety of boat transoms.
Real-World Performance & Handling (The “Experience” Section)
Spec sheets only tell part of the story. The true test of an outboard is how it performs when you’re on the water.
On-Water Performance Review
The 2.1-liter displacement is the star of the show here. Owners consistently report strong low-end torque that gets boats on plane quickly, even when loaded down with gear, fuel, and passengers.
- On a 17-19′ Center Console: Expect rapid acceleration and a time-to-plane of 3-4 seconds. Top speed will typically be in the 40-45 mph range, depending on the hull and load.
- On an 18-21′ Pontoon Boat: This is where the engine truly shines. It provides ample power for leisurely cruising and enough punch for tubing and other water sports. You can expect a comfortable cruising speed of 18-22 mph and a top speed in the low 30s.
- On a 19-21′ Bay Boat: The 115hp is a popular and economical choice for bay boats, offering excellent fuel economy for long days of fishing without sacrificing the ability to get home quickly if weather turns.
Noise, Vibration, and Harshness (NVH)
If you’re upgrading from an older two-stroke engine, the difference will be night and day. The 2017 Mercury 115 Four Stroke is exceptionally smooth and quiet. At idle and trolling speeds, it’s often little more than a hum, allowing for easy conversation and undisturbed fishing. The Advanced MidSection (AMS) effectively eliminates the “buzz” felt through the helm at cruising speeds, reducing fatigue on long runs.
Reliability & Common Issues: An Expert’s Honest Look
Demonstrating real-world experience means being transparent about both the strengths and potential weaknesses of any piece of machinery.
Proven Long-Term Durability
The 2.1L platform used in this engine has been in production for many years and is widely regarded as one of Mercury’s most reliable and bulletproof powerplants. Its simple, over-square design (large bore, short stroke) reduces internal stress and contributes to long engine life. With proper maintenance, it’s not uncommon for these engines to surpass 3,000-4,000 hours of operation.
Potential Problems & Owner-Reported Quirks
No engine is perfect. Based on owner forums and service technician reports, here are a few items to be aware of:
- Shift Interlock Switch: Some owners have reported issues with the shift interlock switch, which can prevent the engine from starting if it fails. This is a relatively minor and inexpensive fix.
- Engine Temperature Sensor: Isolated reports of faulty temperature sensors triggering alarm codes. A diagnostic scan can quickly confirm this.
- Corrosion on Wiring Harness Connectors: In saltwater environments, the electrical connectors can be susceptible to corrosion if not regularly inspected and maintained. Using a dielectric grease is highly recommended.
- Recall Check: It is always critical to check for any open Technical Service Bulletins (TSBs) or recalls with a Mercury dealer using the engine’s serial number. There were no widespread major recalls for this model year, but individual batches may have had specific service campaigns.
Maintenance Schedule & Cost of Ownership
Proactive maintenance is the key to longevity. Here’s a simplified schedule:
- Annual or 100-Hour Service: This is the most critical routine service. It includes changing the engine oil and filter, gear lube, and spark plugs, and inspecting the anodes and water pump impeller. The parts and labor cost for this service typically ranges from $300 – $500 at a dealer.
- Water Pump Impeller: Should be replaced every 2-3 years or 300 hours, whichever comes first. Neglecting this can lead to overheating and severe engine damage.
- 300-Hour Service: A more comprehensive service that includes all 100-hour items plus valve clearance inspection/adjustment and fuel filter replacement.
Expert Tips for Buyers & Owners
Whether you’re in the market for a used 2017 115hp or already own one, these tips will save you time, money, and headaches.
What to Look for When Buying Used
A thorough inspection is non-negotiable. Use this checklist:
- Service Records: This is the #1 priority. A well-documented history is worth more than a low price.
- Computer Diagnostics: Insist on having a Mercury dealer or qualified mechanic hook up a diagnostic computer to check for any active or historical fault codes. This can reveal hidden issues.
- Corrosion Inspection: Pay close attention to the engine block, lower unit, and especially the wiring harness connections for signs of significant corrosion.
- Lower Unit Oil: Check the gear lube. It should be clean and free of metal particles. Milky or metallic oil indicates water intrusion or internal damage.
- Compression Test: A compression test will reveal the health of the internal engine components. All cylinders should be within 10-15% of each other.
- Propeller Condition: Look for nicks, bends, or cracks. A damaged prop can cause vibration and damage the gearcase.
How to Maximize Performance and Lifespan
- Use the Right Oil: Always use Mercury or a NMMA-certified FC-W 4-stroke marine oil. The recommended viscosity is 10W-30 or 25W-40, depending on your climate.
- Fuel Treatment: Consistently use a high-quality ethanol fuel treatment and stabilizer, especially if the engine will sit for more than a month. This prevents phase separation and protects the fuel system from corrosion.
- Prop Selection: Don’t just use the prop that came with the engine. Ensure it’s the correct pitch and diameter to allow the engine to reach its recommended Wide Open Throttle (WOT) RPM range (5800-6400 RPM). An over-propped engine will be sluggish and strain the motor, while an under-propped engine will over-rev and waste fuel. For more on this, see our guide on outboard prop selection.
- Freshwater Flushing: After every saltwater trip, flush the engine with fresh water using “ear muffs” to prevent corrosion and salt buildup in the cooling passages.
How It Stacks Up: The Competition
In 2017, the 115hp class was highly competitive. Here’s a brief look at how the Mercury compared to its two main rivals.
2017 Mercury 115hp vs. Yamaha F115
The Yamaha F115 is a legendary engine known for its stellar reliability.
* Mercury Advantage: The Mercury has a significant displacement advantage (2.1L vs. 1.8L), which typically translates to better low-end torque. It also features the Advanced MidSection for superior vibration control.
* Yamaha Advantage: Yamaha has a perhaps unshakable reputation for bulletproof reliability and an extensive dealer network worldwide. It is also slightly lighter.
2017 Mercury 115hp vs. Suzuki DF115
Suzuki has long been a leader in outboard innovation, particularly in fuel injection.
* Mercury Advantage: The Mercury is often praised for its smoother, quieter operation due to the AMS. Brand loyalty and the extensive Mercury dealer network in North America are also factors.
* Suzuki Advantage: The Suzuki DF115 features a lean-burn control system for class-leading fuel economy at cruising speeds. It is also very lightweight for its class.
| Feature | Mercury 115 | Yamaha F115 | Suzuki DF115 |
|---|---|---|---|
| Displacement | 2.1L | 1.8L | 2.0L |
| Weight | 377 lbs | 369 lbs | 359 lbs |
| Key Feature | Advanced MidSection | Reliability Reputation | Lean-Burn Fuel System |
Frequently Asked Questions (FAQ)
Q: What is the fuel consumption of the 2017 Mercury 115 Four Stroke?
A: At a cruising speed of around 4500 RPM (approx. 32 mph), it consumes about 5.8 gallons per hour. At wide-open throttle (6000 RPM), consumption rises to around 9.8 GPH.
Q: What is the typical price range for a used 2017 Mercury 115hp?
A: As of 2024, prices typically range from $7,500 to $11,000, heavily dependent on total hours, condition, maintenance history, and whether it includes rigging and controls.
Q: Are there any major recalls for the 2017 Mercury 115 Four Stroke?
A: There were no widespread, major recalls. However, always check the engine’s serial number with an authorized Mercury dealer to confirm there are no open Technical Service Bulletins (TSBs) or service campaigns.
Q: What is the recommended oil for a 2017 Mercury 115?
A: Mercury recommends its own 4-Stroke Oil in 10W-30 or 25W-40 viscosity, or any NMMA-certified FC-W 4-stroke marine oil.
Q: How does the 2017 model differ from the 2018 or 2019 Mercury 115?
A: The core 2.1L engine remained largely unchanged, which is a testament to its solid design. Later models may have received minor ECU updates, new branding, and color schemes. The most significant changes came with the introduction of the new 115hp ProXS model.
Q: What size boat is the Mercury 115hp best suited for?
A: It is an ideal match for boats between 17 and 21 feet, including center consoles, bay boats, pontoon boats, and small offshore fishing boats. For heavier pontoons or large, heavy deep-V hulls, consider moving up to a 150hp engine.
Conclusion & Final Verdict
The 2017 Mercury 115 Four Stroke stands as a testament to the principle of refined, proven engineering. Its key strengths are its exceptional fuel efficiency, remarkably smooth and quiet operation, and a well-earned reputation for long-term reliability. The larger 2.1-liter displacement gives it a tangible performance edge in low-end torque, making it feel stronger than its horsepower rating suggests.
The primary considerations for a potential buyer are the standard due diligence required for any used outboard—scrutinizing service records and having a mechanic perform a pre-purchase inspection to rule out any minor electrical gremlins.
Ready to find your 2017 Mercury 115? Use the checklist in this article to inspect potential purchases, or contact a certified Mercury Marine dealer for expert service and support.
For boaters seeking a perfect blend of modern efficiency and proven reliability, the 2017 Mercury 115 Four Stroke remains a top-tier choice that delivers confidence on every voyage.