1. Boat Outboard Engines To Buy
  2. sku: 24141896456602773
  3. EFMOTORSHOP 339-7452A15

EFMOTORSHOP 339-7452A15 Cdi Box Switch Power Pack Outboard 211100122084 339-7452A19 18-5777

fits make: Mercury.

339-7452a15 Efmotorshop 211100122084 339-7452a19 Switch Box Cdi Power Pack Fit Mercury Outboard 18-5777

( Brand: Efmotorshop ), ( Part Type: Switch Box ), ( Color: As The Pictures Shown ), ( Country Of Origin: China ), ( Features: Durable ), ( Warranty: 90 Day ), ( UPC: 211100122084 )

Review EFMOTORSHOP Switch Box Cdi Power Pack Fit Mercury Outboard

The **EFM MotorShop part number 211100122084**, identified as the **339-7452A19 Switch Box/CDI Power Pack**, is a critical electrical component designed specifically for **Mercury outboard motors**, particularly those in the **339 horsepower series** (such as the **339-7452A15** model). This high-performance switch box serves as the central hub for managing the ignition, electrical distribution, and power delivery within the engine s control system, ensuring seamless operation between the ignition coil, starter motor, and other essential circuits. Engineered with precision, this component integrates a **CDI (Capacitor Discharge Ignition) power pack**, which enhances ignition efficiency by delivering a high-voltage spark with greater consistency and reliability compared to traditional ignition systems. The robust construction of the switch box typically featuring durable plastic or metal housings protects sensitive internal wiring and connectors from environmental stressors like moisture, vibration, and corrosion, which are common challenges in marine environments. Compatible with the **18-5777** wiring harness and other related Mercury outboard components, this switch box is a direct replacement for factory units, ensuring compatibility with both stock and aftermarket modifications. Whether used in recreational boats, fishing vessels, or performance cruisers, this component is essential for maintaining optimal engine performance, fuel efficiency, and longevity, making it a must-have for any Mercury 339 outboard owner seeking reliable electrical functionality.

### **Pros and Cons of buying a EFMotorShop 211100122084 (CDI Power Pack for Mercury Outboards 339-7452A19 and 18-5777)**

#### **Overview**

This product is a **CDI (Capacitor Discharge Ignition) power pack** designed for **Mercury outboard motors**, specifically models **339-7452A19** and **18-5777**. It is sold under the part number **211100122084** and is intended to replace or upgrade the factory CDI unit, improving ignition reliability and performance.

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### **Pros**

1. **Compatibility with Specific Mercury Models**

- The unit is **directly compatible** with the **Mercury 339-7452A19** and **18-5777** outboard engines, reducing the risk of purchasing an incorrect part.

2. **Potential for Improved Ignition Performance**

- A high-quality CDI module can provide **more consistent spark**, reducing misfires and improving engine starting and throttle response.

- Some users report **better cold-start performance** compared to failing factory units.

3. **Easy Installation**

- CDI units are typically **plug-and-play replacements**, requiring minimal wiring knowledge.

- No major modifications to the engine are usually needed beyond removing the old unit and installing the new one.

4. **Cost-Effective Repair Option**

- Replacing a faulty CDI is often **cheaper than overhauling or replacing the entire ignition system** or engine components affected by misfires (e.g., spark plugs, coils, or fuel system issues).

- Pricing is generally **affordable** compared to labor-intensive repairs.

5. **Extended Engine Life**

- A properly functioning CDI prevents **carbon buildup, fouled spark plugs, and excessive wear on ignition components**, which can prolong the life of the engine.

6. **Aftermarket Support and Availability**

- Since this is a **common replacement part**, it is widely available from **Mercury dealers, marine parts suppliers, and online retailers**, making replacements easier if needed.

7. **Potential for Tuning and Performance Enhancements**

- Some aftermarket CDI units offer **adjustable timing or higher voltage output**, which can be beneficial for **performance tuning** (though this is less common for stock applications).

---

### **Cons**

1. **Potential for Counterfeit or Low-Quality Units**

- Purchasing from **unverified sellers** (especially online marketplaces) may result in **fake or substandard parts** that fail prematurely.

- Always **verify the seller s reputation** and check for **authentic Mercury or EFMotorShop branding**.

2. **Mixed User Experiences with Performance Gains**

- While some users report **noticeable improvements**, others may not see a **dramatic difference** if the original issue was not purely ignition-related (e.g., fuel delivery, compression, or mechanical wear).

- If the engine has **severe internal damage**, replacing just the CDI may not fully resolve performance issues.

3. **Limited Warranty or Return Policy Risks**

- Some sellers offer **short or no warranties**, meaning if the unit fails quickly, you may be **out of luck without a return option**.

- Always **check the warranty terms** before purchasing.

4. **Possible Compatibility Issues with Modified Engines**

- If the engine has been **modified (e.g., turbocharged, high-compression kits, or aftermarket ignition systems)**, the stock CDI may not be sufficient, and a **higher-performance unit** may be needed.

5. **DIY Installation Risks**

- While installation is usually straightforward, **incorrect wiring or improper grounding** can lead to **electrical shorts, no-start conditions, or damage to the engine s ECU**.

- If unsure, **consult a marine mechanic** to avoid costly mistakes.

6. **Age of the Part and Obsolescence**

- Older Mercury models may have **discontinued parts**, making future replacements harder.

- Always confirm that the **part number is still supported** by the manufacturer.

7. **Potential for Overkill on Stock Engines**

- If the engine is **running fine**, replacing a working CDI may not be **necessary**, making the purchase an **unjustified expense**.

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### **Conclusion**

The **EFMotorShop 211100122084 CDI Power Pack** is a **reliable and cost-effective solution** for **Mercury 339-7452A19 and 18-5777 outboards** experiencing **ignition-related issues**. It offers **improved reliability, easier installation, and potential performance benefits**, making it a **strong replacement option** for failing factory units.

However, **buyers should be cautious** about **purchasing from untrusted sellers**, ensuring **proper compatibility**, and understanding that **this is not a cure-all for severely worn engines**. If the engine has **mechanical or fuel system problems**, addressing those first may yield better long-term results.

For **most users dealing with misfires, poor starting, or CDI failure**, this part is a **practical and worthwhile investment**.

---

### **Recommendation**

- **Buy from an authorized dealer or reputable marine parts supplier** (e.g., Mercury Marine, local marine shops, or well-reviewed online retailers).

- **Verify the exact model compatibility** before purchasing to avoid mismatches.

- **Consider a short-term test run** if unsure some sellers offer **return policies** for defective units.

- **If the engine has other issues**, address those first (e.g., spark plugs, fuel filters, or mechanical wear).

- **Follow installation instructions carefully** to prevent electrical issues.

- **Keep a backup or spare** in case of future failures, especially for frequently used boats.

**Final Verdict:** **Worth purchasing for ignition-related problems**, but **research and caution are advised** to ensure a successful replacement.

Details:

Condition: 100% Brand New. Features: Made of high-quality materials, more durable. 339-7452A19 Switch Box CDI Power Pack Fit Mercury Outboard 339-7452A15 18-5777 For 339-7452A15. Do not open a return request.

Specifications. Easy to install and reliable use. 339-7452A19 Switch Box CDI Power Pack Fit Mercury Outboard 339-7452A15 18-5777. Appreciate your kindly understanding and cooperation.

Rugged and durable. Highly matching the original equipment. Unresolved issues without prior communication may delay resolution. We ll resolve issues promptly.

Fitment: 6 HP MH 1994 -1998. Color: Black.

specifications ouboaen:

  • for makes: Mercury
  • brand: Efmotorshop
  • part type: Switch Box
  • color: As The Pictures Shown
  • country of origin: China
  • features: Durable
  • warranty: 90 Day
  • upc: 211100122084

shipping ouboaen:

  • transit: 5-11 Days
  • type: Fixed
  • cost: $0.00
  • service: Standard
  • class: Standard

offer ouboaen:

  • quantity: 1
  • best offers: True
  • started: May 23, 2026
  • sold: 0
  • options: Ship-to-home
  • availability: In Stock

returns ouboaen:

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

payments ouboaen:

  • credit card: Discover
  • wallet: Google-pay
  • other

seller ouboaen:

  • # reviews: 1950
  • city: Chino, California
  • rating: 99.1%

general ouboaen:

  • Boat Parts > Outboard Engines Components > Ignition Starting Systems
  • condition: New
for makes: mercury, part type: switch box, country of origin: china, features: durable, warranty: 90 day,
category: boat parts > outboard engines components > ignition starting systems, color: as the pictures shown, sku: 24141896456602773,
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