# 333-3213A3 Mercury Switch Box | Genuine Used Part

🔧 Product Description

  

Genuine Mercury Switch Box Assembly - Part Number: 333-3213A3

  

A genuine Mercury ignition switch box assembly used on selected early Mercury 4-cylinder Thunderbolt ignition systems. This 4-post switch box is associated with classic Mercury 500 / 50HP and Mercury 650 / 65HP two-stroke outboards and must be matched by original switch-box number and wiring layout.

  

⚙️ Key Features

  

• Genuine Mercury switch box assembly

• Correct Mercury part number 333-3213A3

• Early 4-post Thunderbolt ignition switch box

• Used on selected Mercury 50HP and 65HP 4-cylinder two-stroke engines

• Red / white / blue / green 4-post wiring layout must match the original unit

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 333-3213A3 current Mercury switch box assembly reference

• 333-3213 related base switch box reference

• 3213A3 formatted Mercury switch box reference

  

OEM / Related Numbers:

  

• 333-3213A3

• 3333213A3

• 3213A3

• 333-3213

• 3333213

• Switch box assembly

• Ignition switch box

• 4-post switch box

• Red / white / blue / green terminal layout

  

Aftermarket / Verified Equivalents:

  

• Pro Marine: 19052

• Maxrules: 19052

  

🚤 Compatibility

  

Commonly used on:

  

• Early Mercury 4-cylinder two-stroke Thunderbolt ignition systems

  

Typically suits:

  

• Engine models:

• Mercury 500 / 50HP 4-cylinder - 1968-1975

• Mercury 500 / 50HP - serial 4357640 to 5531629

• Mercury 50HP 4-cylinder Thunderbolt ignition

• Mercury 650 / 65HP 4-cylinder - late-1960s applications

• Mercury 65HP 4-cylinder Thunderbolt ignition

  

• HP Range: commonly 50HP - 65HP

• Engine Type: Mercury 4-cylinder two-stroke outboard with early Thunderbolt switch-box ignition

• Year Range: Approximately 1968 - 1975 for common 50HP / 65HP applications

• Serial Range: Mercury 500 / 50HP parts-family range includes serial 4357640 to 5531629; 65HP applications must be checked by original serial-numbered ignition diagram and 4-post switch-box wiring.

  

🔌 Function

  

The switch box stores and releases ignition energy to the coil circuit when triggered, allowing the engine to produce spark at the correct timing point.

  

Common signs of failure:

  

• No spark

• Weak or intermittent spark

• Engine starts then loses spark

• No-start after trigger, coil and wiring checks

• Spark returns when switch box is substituted

• Internal failure caused by age, heat or vibration

• Incorrect spark output from damaged terminals or wiring

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 60.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Electronic Components | ECU CDI & Electrical Parts

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 60.00 AUD | In stock |

## Images

- 333-3213A3 Mercury Switch Box | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/333-3213a3-mercury-switch-box-genuine-used-part)
> Updated: 2026-06-29