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Marine & Outboard Spark Plugs

NGK Laser Iridium Spark Plug IZFR6J (4462)

SKU: GB-IZFR6J

$44.30
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The NGK IZFR6J (Stock No. 4462) is a premium Laser Iridium resistor spark plug designed for selected Mercury OptiMax/Pro XS and Tohatsu TLDI two-stroke outboards. Featuring a fine-wire iridium centre electrode, platinum ground electrode and extended projection, it provides dependable ignition and excellent durability. Its M14 × 1.25 thread, 19 mm reach, 16 mm hex and 0.8 mm nominal gap suit demanding direct-injection marine engines.

Key benefits

Key Benefits

  • - NGK Stock Number: 4462
  • - Laser Iridium construction
  • - Fine-wire iridium centre electrode
  • - Platinum ground electrode
  • - Extended projection design
  • - Built-in resistor – approximately 5 kΩ
  • - Excellent electrode wear resistance
  • - 0.8 mm / 0.032" nominal gap
  • - NGK heat range 6
  • - Flat gasket seat
  • - Suitable for selected Mercury DFI/OptiMax/Pro XS engines
  • - Suitable for selected Tohatsu TLDI direct-injection outboards

Specifications & Dimensions

  • - Brand: NGK
  • - Part Number: IZFR6J
  • - NGK Stock Number: 4462
  • - Type: Laser Iridium
  • - Thread Diameter: 14 mm / 0.551"
  • - Thread Size: M14 × 1.25
  • - Thread Reach: 19 mm / 0.750"
  • - Hex / Spanner Size: 16 mm / 5/8"
  • - Nominal Spark Gap: 0.8 mm / 0.032"
  • - NGK Heat Range: 6
  • - Seat: Flat / gasket
  • - Resistor: Yes – approximately 5 kΩ
  • - Centre Electrode: Fine-wire iridium
  • - Centre Electrode Core: Copper
  • - Ground Electrode: Platinum
  • - Centre Electrode Projection: Extended
  • - Terminal: Solid
  • - Sealing Washer: Yes

Compatible Outboard Motors

  • Mercury OptiMax / Pro XS
  • - Mercury 175 HP Pro XS V6 2.5L — Engine No. 1B516339–2B535624
  • - Mercury 200 HP Pro XS V6 3.0L — Engine No. 1B912786–2B535571
  • - Mercury 225 HP Pro XS V6 3.0L — Engine No. 1B104549–2B535608
  • - Mercury 250 HP Pro XS V6 3.0L — Engine No. 1B426561–2B535608

Mercury 2.5XS / Sport XS / XS

  • - Mercury 2.5XS 225 HP, 2.5L DFI — Engine No. 0T997974–1E000796
  • - Mercury 225 HP Sport XS V6 2.5L — Engine No. 1E002584–1E050825
  • - Mercury 225 HP Sport XS V6 3.0L — Engine No. 1E000797–1E002583
  • - Mercury 225 HP XS V6 2.5L — Engine No. 1E002584–1B792195
  • - Mercury 250 HP Sport XS V6 2.5L — Engine No. 1E002342–1E052994
  • - Mercury 250 HP XS V6 3.0L — Engine No. 0T818043–1E053958

Tohatsu TLDI Outboards

  • - Tohatsu MD40B2 – 40 HP TLDI
  • - Tohatsu MD50B2 – 50 HP TLDI
  • - Tohatsu MD70B – 70 HP TLDI
  • - Tohatsu MD90B – 90 HP TLDI

Important Tohatsu Distinction

  • Tohatsu's current replacement-plug chart separates the applications
  • - MD40/50B → PZFR6H
  • - MD40B2 through MD90B → IZFR6J
  • - MD75/90C2 → IZFR6Q
  • - MD115A/115A2 → IZFR5J

Cross-Reference Part Numbers

  • - NGK: IZFR6J
  • - NGK Stock No.: 4462
  • - Tohatsu: 97011-1110M
  • - Tohatsu: 9701-1-1110
  • - Mercury / Quicksilver: 33-843220001

Signs the Spark Plug Needs Replacing

  • - Difficult starting
  • - Rough or unstable idle
  • - Engine misfire
  • - Hesitation during acceleration
  • - Reduced engine power
  • - Poor high-RPM operation
  • - Increased fuel consumption
  • - Carbon or fuel fouling
  • - Excessive electrode erosion
  • - Corrosion
  • - Cracked ceramic insulator
  • - Damaged sealing washer

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