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338-4733A2 Mercury Switch Box | Genuine Used Part

338-4733A2 Mercury Switch Box | Genuine Used Part

$60.00 AUD
$60.00 AUD
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✓ Authorised Volvo Penta Dealer · Genuine used marine parts · Ships Australia-wide

🔧 Product Description

Genuine Mercury Switch Box / CDI Module - Part Number: 338-4733A2

A genuine Mercury switch box used on selected vintage Mercury and Mariner two-cylinder outboard ignition systems. This CDI module controls ignition triggering and coil firing where the original switch-box number, wiring layout and serial range match.

⚙️ Key Features

  • Genuine Mercury switch box / CDI module
  • Correct OEM part number 338-4733A2
  • Cross-references with 332-4911A2, 332-4911A5 and 332-4911A8
  • Used on selected Mercury / Mariner 20HP and 40HP two-cylinder outboards
  • Match by serial range, wiring colours and ignition-system diagram

🚤 Compatibility

Commonly used on

  • Mercury / Mariner 20HP and 40HP vintage CDI ignition systems

Typically suits

  • Engine models:
  • Mercury 20HP Model 200 - 1973-1977, serial 3537531 to 4709592
  • Mercury 40HP Model 402 electric start - 1972-1974, serial 3336258 to 3859434
  • Mercury 40HP Model 402 manual start - 1972-1974, serial 3336258 to 4117709
  • Mercury 40HP Model 402 electric start - 1975-1977, serial 4117710 to 4860102
  • Mercury 40HP manual start - 1975-1981, serial-controlled applications up to 5823917
  • Mercury 40HP electric start - 1978-1981, serial 4860103 to 5823917
  • Mercury / Mariner 20HP and 40HP ignition systems where the original switch box is 338-4733A2 or 332-4911A-series
  • HP Range: 20HP - 40HP
  • Engine Type: Mercury / Mariner two-cylinder two-stroke CDI ignition system
  • Year Range: approximately 1972 - 1981 depending on engine model and start type
  • Serial Note: Match by exact Mercury / Mariner serial number, wiring colours, switch-box mounting, trigger/stator layout and original switch-box number before installation.

🔌 Function

The switch box receives ignition trigger and stator inputs, stores ignition energy and fires the ignition coil at the correct timing point.

⚠️ Common Signs of Failure

  • No spark
  • Weak or intermittent spark
  • Spark on one cylinder only
  • Hard starting
  • Engine starts then loses spark
  • Misfire under load
  • Heat-related ignition failure
  • Spark returns when a known-good switch box is fitted

🔄 Supersession & Cross Reference

OEM Supersession Chain

  • 338-4733 Mercury switch box reference
  • 338-4733A2 Mercury switch box reference
  • 332-4911A2 related Mercury switch box reference
  • 332-4911A5 related Mercury switch box reference
  • 332-4911A8 related Mercury switch box reference

OEM / Related Numbers

  • 338-4733A2
  • 3384733A2
  • 338-4733
  • 3384733
  • 332-4911A2
  • 3324911A2
  • 332-4911A5
  • 3324911A5
  • 332-4911A8
  • 3324911A8
  • Switch box
  • CDI module
  • Ignition module
  • Capacitor discharge ignition box
  • Mercury 20HP / 40HP switch box

Aftermarket / Verified Equivalents

  • CDI Electronics: 114-4911
  • Sierra: 18-5787
  • Mallory: 9-25105
  • Aftermarket replacement for 338-4733A2 / 332-4911A2 / 332-4911A5 / 332-4911A8

📦 Condition

  • Genuine used part
  • Removed from running engine where applicable
  • In good working condition unless otherwise stated

Shipping & Delivery

Flat-rate shipping Australia-wide — $14.99 per order, no matter how many parts you add. Orders dispatch from our Kadina, South Australia store. Need it urgently or want to collect in person? Call us on 0412 532 984 before ordering.

Returns & Warranty

14-day change-of-mind returns — if it's not right or you ordered the wrong part, send it back within 14 days in the condition you received it for a refund or exchange. Full details in our Refunds & Returns policy.

Not sure this fits?

Ask us before you buy — we check part numbers and fitment every day. Call 0412 532 984 (Mon–Fri 8.30am–4.30pm) or message us through the contact page with your engine or vehicle details.

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