1. Boat Outboard Engines To Buy
  2. sku: 24111170365879793
  3. MERCURY 885557085

MERCURY 885557085 Dfi Ecm Engine Control Module 135HP

fits make: Mercury.

885557085 Mercury Good Used Oem 135hp Dfi Ecm Engine Control Module Part #

( Manufacturer Part Number: 885557085 ), ( Part Type: Ecm Control Engine Module ), ( Country Of Origin: United States )

Review MERCURY Good Used Oem 135hp Dfi Ecm Engine Control Module Part

The **Mercury 885557085 135HP DFi Engine Control Module (ECM)** is a high-performance, factory-original component designed specifically for Mercury outboard motors equipped with the **DFi (Digital Fuel Injection)** system, ensuring precise engine management for optimal power, efficiency, and reliability. This ECM is engineered to regulate critical functions such as fuel delivery, ignition timing, and throttle response, allowing the motor to operate at peak performance while maintaining smooth operation under varying load conditions. Built with advanced digital circuitry, the module interfaces seamlessly with the motor s sensors including the throttle position sensor, crankshaft position sensor, and water temperature sensor to deliver real-time adjustments that enhance throttle response, fuel economy, and overall engine longevity. Whether used in marine applications like fishing boats, personal watercraft, or recreational vessels, this ECM is a critical component for maintaining the motor s factory-tuned performance, ensuring consistent power output and reducing the risk of mechanical stress or premature wear. Ideal for both new installations and replacements, the **885557085 ECM** is a direct-fit solution for Mercury outboards such as the **4.6L, 5.0L, and 6.0L DFi engines**, including models like the **Mercury 200 400 HP series**, making it a must-have for enthusiasts and professionals seeking reliable, high-performance marine propulsion. Its robust construction and compatibility with Mercury s diagnostic systems also simplify troubleshooting and maintenance, ensuring that your outboard runs with the same precision and power as it did when it left the factory.

The **Mercury 885557085 135hp DFi ECM (Engine Control Module)** is a replacement part for older Mercury outboard motors, particularly those from the 1990s to early 2000s. Below is a detailed breakdown of its pros and cons, followed by a conclusion and recommendation.

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### **Pros of buying a Mercury 885557085 135hp DFi ECM**

1. **Compatibility with Older Mercury Motors**

The ECM is designed specifically for Mercury outboards in the 135hp DFi (Direct Fuel Injection) series, including models like the **Mercury 135hp DFi (e.g., 1998 2003 models)**. This ensures a direct fit without major modifications, reducing installation hassles.

2. **Restores Original Performance**

A faulty or failing ECM can cause poor throttle response, rough idling, or complete engine failure. Replacing it with an OEM or high-quality aftermarket unit (like this one) can restore the motor to near-original performance, including proper fuel delivery, ignition timing, and emissions compliance.

3. **Cost-Effective Alternative to Motor Replacement**

Replacing an entire outboard engine can cost thousands of dollars, whereas an ECM typically ranges from **$200 $500**, making it a far more affordable solution for engines that are otherwise mechanically sound.

4. **Improved Reliability and Longevity**

If the ECM was the root cause of issues (e.g., check engine lights, stalling, or poor fuel economy), a new unit can prevent further damage to other components like the fuel pump, injectors, or ignition system. This can extend the life of the motor.

5. **Easier to Install Than a Full Engine Swap**

Unlike replacing an entire engine, which requires disassembly, labor, and professional help, an ECM swap is often a **DIY-friendly job** for someone with basic mechanical skills. It typically involves removing the old unit, connecting new wiring harnesses, and programming it (if required).

6. **Warranty Coverage (If Purchased from a Reputable Seller)**

Some sellers offer warranties (e.g., 30 90 days) or return policies, providing peace of mind in case of defects. OEM units from Mercury or authorized dealers may come with limited warranties.

7. **Supports Emissions Compliance**

Older DFi engines were designed with specific ECM firmware to meet emissions standards. A new ECM ensures the motor continues to pass emissions tests if required (e.g., for registration or boating regulations).

8. **Available from Multiple Sellers**

The part is widely available on platforms like **eBay, Amazon, Mercury dealers, and specialty marine parts stores**, giving buyers options for pricing and authenticity.

---

### **Cons of buying a Mercury 885557085 135hp DFi ECM**

1. **Age and Potential Wear of the Motor**

If the outboard motor is **15 years old**, other components (e.g., fuel injectors, ignition coils, fuel pump, or mechanical parts like the lower unit) may be worn out. Replacing just the ECM won t fix these issues, and the motor may still fail prematurely.

2. **Compatibility Issues with Non-OEM Units**

While this ECM is a **direct replacement**, some aftermarket or refurbished units may not work perfectly if they are **not programmed correctly** or lack proper calibration. Cheap or counterfeit units may cause **poor performance, no-start conditions, or even damage to the motor**.

3. **Programming or Relearning May Be Required**

Some ECM replacements require **relearning or programming** to sync with the motor s sensors. This may involve:

- Using a **Mercury diagnostic tool** (e.g., Mercury Marine s diagnostic software).

- Visiting a **dealer or marine technician** for proper recalibration.

- If the seller doesn t include programming, this could add **$100 $300 in extra labor costs**.

4. **Risk of Counterfeit or Low-Quality Units**

Buying from **unverified sellers** (especially on platforms like eBay or Facebook Marketplace) increases the risk of receiving a **fake, refurbished, or damaged ECM**. This can lead to **no performance improvement or further motor damage**.

5. **Limited Lifespan of the ECM Itself**

While ECMs are designed to last the life of the motor, **15 20 years of use** can degrade the internal components (e.g., capacitors, microchips). A new ECM may not last as long as it would in a newer motor, and failure could recur.

6. **Potential for Additional Hidden Issues**

If the motor has **mechanical problems** (e.g., worn pistons, timing issues, or fuel system clogs), replacing the ECM alone won t resolve them. A **full diagnostic** (e.g., compression test, fuel pressure check) may be needed before installation.

7. **Wiring Harness or Sensor Failures**

The ECM relies on **sensors (e.g., crankshaft position, throttle position, oxygen sensor)** and a **clean wiring harness**. If these are damaged or corroded, the new ECM may not function correctly. Inspecting and cleaning these components is essential.

8. **No Performance Upgrades**

Unlike some aftermarket ECMs (e.g., for tuning), this is a **stock replacement**. It won t improve horsepower, torque, or fuel efficiency beyond the motor s original specifications.

9. **Dealer vs. Aftermarket Cost Disparity**

An **OEM Mercury ECM** from an authorized dealer will cost more (**$400 $600**) than a generic aftermarket unit (**$200 $300**). The aftermarket option may save money but carries higher risk if not from a trusted brand (e.g., **Mercury Marine, Sea-Doo, or reputable marine parts suppliers**).

10. **Environmental and Safety Concerns**

Older DFi engines were not designed with modern emissions standards in mind. If the motor is used frequently, the **ECM may need updates** to comply with current regulations, which could require professional intervention.

---

### **Conclusion**

The **Mercury 885557085 135hp DFi ECM** is a **cost-effective and practical solution** for restoring functionality to an older Mercury outboard motor, provided the motor itself is mechanically sound. It is ideal for:

- **Boat owners** who want to **revive a struggling 135hp DFi motor** without a full engine replacement.

- Those who have **confirmed ECM failure** (e.g., check engine light, no-start, poor performance).

- DIYers comfortable with **basic electrical work and potential programming**.

However, it is **not a universal fix** if the motor has **mechanical, fuel system, or sensor issues**, those must be addressed first. Additionally, **buying from a reputable seller** and ensuring proper installation (including programming if needed) are critical to success.

---

### **Recommendation**

1. **Verify Motor Health First**

Before purchasing the ECM, have a **marine mechanic inspect** the motor for:

- **Fuel system issues** (clogged injectors, bad fuel pump).

- **Mechanical wear** (piston rings, timing belt, lower unit seals).

- **Sensor failures** (crankshaft position sensor, throttle position sensor).

If other components are failing, prioritize those repairs.

2. **Buy from a Trusted Source**

- **Authorized Mercury Marine dealer** (for OEM warranty).

- **Reputable marine parts supplier** (e.g., **MarineMax, West Marine, or specialty ECM sellers**).

- Avoid **unknown sellers** on eBay or Facebook unless they have **verified reviews and return policies**.

3. **Check for Programming Requirements**

Some ECMs require **relearning** with a diagnostic tool. Ask the seller if programming is included or if you ll need to arrange it separately.

4. **Consider a Refurbished vs. New Unit**

- **New OEM ECM** ($400 $600) Best for long-term reliability.

- **Refurbished/Remanufactured ECM** ($200 $300) Cheaper but may have shorter lifespan.

- **Aftermarket Generic ECM** ($150 $250) Riskier; only buy from well-reviewed brands.

5. **Install Properly or Hire a Professional**

- If comfortable with electronics, follow **Mercury s installation guide**.

- If unsure, have a **marine technician** install it to avoid wiring mistakes.

6. **Test After Installation**

- Run a **diagnostic check** to ensure the ECM is communicating with the motor.

- Monitor for **check engine lights, rough idling, or stalling** these could indicate improper installation or remaining issues.

7. **Budget for Contingencies**

- Allocate extra funds for **programming, additional sensors, or unexpected repairs**.

- If the motor is very old, consider whether **replacing the entire engine** (or upgrading to a newer model) might be more cost-effective long-term.

---

### **Final Verdict**

**Buy the ECM if:**

Your **135hp Mercury DFi motor is mechanically sound** but has ECM-related symptoms.

Details:

This listing is for a Good Used OEM Mercury / Mariner 135 HP ECM Engine Control Module, Part # 885557085. Ships USPS or UPS carrier selected based on location Shipping $8.00.

part #: 885557085 price

  • $275.00

specifications ouboaen:

  • for makes: Mercury
  • mpn: 885557085
  • part type: Ecm Control Engine Module
  • country of origin: United States

returns ouboaen:

  • policy: Returns Accepted
  • paid by: Seller
  • time: 30 Days

payments ouboaen:

  • wallet: Paypal
  • credit card: Visa
  • other
  • cash

offer ouboaen:

  • started: May 22, 2026
  • sold: 0
  • quantity: 1
  • availability: In Stock
  • options: Ship-to-home

general ouboaen:

  • condition: Used
  • Boat Parts > Outboard Engines Components > Other

seller ouboaen:

  • city: Scottsville, Kentucky
  • # reviews: 29111
  • rating: 99.7%

shipping ouboaen:

  • service: USPS Ground Advantage
  • cost: $8.00
  • type: Fixed
  • transit: 5-11 Days
  • carrier: USPS
  • class: Standard
for makes: mercury, part type: ecm control engine module, country of origin: united states,
category: boat parts > outboard engines components, sku: 24111170365879793,
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1 offer $275.00 USD
  • Used. Offer #1 priced at $275.00 + $8.00 shipping estimate = $283.00* total. +$8.00 shipping

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