# LFR5AIX-11 NGK Iridium Spark Plug | Genuine NGK Spark Plug

## 🔧 Product Description

**NGK Iridium Spark Plug – Part Number: LFR5AIX-11**

Iridium NGK spark plugs offer a longer service life than a standard nickel-tipped spark plug: while nickel-alloy plugs offer a service life of roughly 20,000-40,000km, NGK Iridium IX spark plugs offer a service life of up to 60,000km, so fewer replacements are needed over time despite the higher initial cost.

Precious-metal spark plugs like the NGK Iridium IX also offer higher ignitability, achieved with an exposed fine-tip centre electrode that promotes superior flame growth compared with a standard spark plug. Iridium has a much higher melting point (2410°C) than nickel (1453°C), allowing the centre electrode diameter to be reduced from 2.5mm to 0.6mm – a smaller electrode mass that reduces the impedance to flame progress, helping acceleration, fuel consumption and idle quality.

## ⚙️ Key Features

-   Fine iridium-tipped centre electrode for a slow wear rate and stable idle
-   Longer service life than standard nickel plugs
-   Trivalent metal plating provides superior anti-corrosion and anti-seizing properties
-   Corrugated ribs reduce the risk of flashover
-   Pure alumina silicate ceramic insulator, providing superior strength and better heat transfer
-   Copper core aids in heat removal
-   Triple seals prevent leakage

## 📏 Specifications

-   NGK stock number: 4469
-   Thread: 14 mm
-   Reach: 26.5 mm (1.04 in)
-   Hex: 16 mm (5/8 in)
-   Seat: Gasket
-   Terminal: Solid
-   Type: Projected, Wide Gap

## 🚘 Application

Listed in NGK's application charts for marine, motorcycle, ATV and snowmobile equipment and automotive vehicles. The chart shows a 1.0 mm gap for these engines, but check it against your engine's manual before fitting.

-   Mariner 225 EFI (225 HP) – Outboard Engine
-   Mariner 90 (90 HP, 2000) – Outboard Engine
-   Mariner 75 (75 HP, 2000) – Outboard Engine
-   Mercury FOURSTROKE 225, SERIAL # 0T653945 AND UP (225 HP) – Outboard Engine
-   Mercury FOURSTROKE 90, 1596CC, SERIAL 0G960500-1B366822 (90 HP) – Outboard Engine
-   Mercury FOURSTROKE 75, BODANESE, 1596CC, SERIAL 0G960500-1B366822 (75 HP) – Outboard Engine
-   Yamaha LF250 (250 HP, 2005) – Outboard Engine
-   Yamaha F225TUR, TXR (225 HP, 2010-2006) – Outboard Engine
-   Yamaha LF225 (225 HP, 2005-2002) – Outboard Engine
-   Yamaha LF225TUR, TXR (225 HP, 2010-2006) – Outboard Engine
-   Yamaha LX225 (225 HP, 2003-2002) – Outboard Engine
-   Yamaha F200TXR (200 HP, 2010-2006) – Outboard Engine
-   Yamaha LF200 (200 HP, 2005-2002) – Outboard Engine
-   Yamaha LF200TXR (200 HP, 2010-2006) – Outboard Engine
-   Yamaha F150,TJR, TLR, TXR (150 HP) – Outboard Engine
-   Yamaha LF150 (150 HP, 2013-2004) – Outboard Engine
-   Yamaha LF150TXR (150 HP, 2011-2006) – Outboard Engine
-   Yamaha F100 (100 HP, 2002-1999) – Outboard Engine
-   Yamaha F90, 4-CYL (90 HP) – Outboard Engine
-   Yamaha F90TJR, TLR, TXR (90 HP, 2010-2006) – Outboard Engine
-   Yamaha F80 (80 HP, 2002-1999) – Outboard Engine
-   Yamaha F75, 4-CYL (75 HP) – Outboard Engine
-   Yamaha F75TLR (75 HP, 2011-2006) – Outboard Engine
-   Chrysler 200 (2017-2015) – 3-16 per engine
-   Chrysler 300 (2017-2009) – 3-16 per engine

That is the 25 most common of 100 applications NGK's charts list for this plug – ask us to check yours.

## 🔄 Supersession & Cross Reference

NGK's cross-reference tables list this plug against these part numbers.

-   DENSO: 4703, 5343, 5617, IKH16, IKH16TT, VKH16
-   Autolite: XP5325, XP5325DP2
-   Bosch: 9609, FR8MII33X
-   Champion: 7975

## 📦 Condition

-   Brand new genuine product
-   Supplied in original packaging

## Details

- **Price:** 61.0 AUD
- **Vendor:** NGK
- **Type:** Ignition & Controls

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 61.00 AUD | In stock |

## Images

- LFR5AIX-11 NGK iridium spark plug
- LFR5AIX-11 NGK iridium spark plug firing end

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/lfr5aix-11-ngk-iridium-spark-plug-genuine-ngk-spark-plug)
> Updated: 2026-09-03