# LFR6AIX-11 NGK Iridium Spark Plug | Genuine NGK Spark Plug

## 🔧 Product Description

**NGK Iridium Spark Plug – Part Number: LFR6AIX-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: 6619
-   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.

-   Mercury FOURSTROKE 115, 1.7L, SERIAL 0T178500-1B366822 (115 HP) – Outboard Engine
-   Yamaha F350, 5.3L V8 (350 HP) – Outboard Engine
-   Yamaha F350A (350 HP, 2013-2011) – Outboard Engine
-   Yamaha F350TUR, TXR (350 HP, 2010-2006) – Outboard Engine
-   Yamaha LF350A (350 HP, 2013-2011) – Outboard Engine
-   Yamaha LF350TUR, TXR (350 HP, 2010-2006) – Outboard Engine
-   Yamaha F300, 4.2L V6 (300 HP) – Outboard Engine
-   Yamaha F300A, 4.2L V6 (300 HP, 2013-2011) – Outboard Engine
-   Yamaha F300TUR, TXR (300 HP, 2010-2006) – Outboard Engine
-   Yamaha LF300A, 4.2L V6 (300 HP, 2013-2011) – Outboard Engine
-   Yamaha LF300TUR, TXR (300 HP, 2010-2006) – Outboard Engine
-   Yamaha F250, 3.3L V6 (250 HP) – Outboard Engine
-   Yamaha F250, 4.2L V6 (250 HP) – Outboard Engine
-   Yamaha F250A, 4.2L V6 (250 HP, 2013-2011) – Outboard Engine
-   Yamaha F250BTUR, BTXR (250 HP, 2010-2006) – Outboard Engine
-   Yamaha F250TUR, TXR (250 HP, 2010-2006) – Outboard Engine
-   Yamaha LF250, 3.3L V6 (250 HP, 2013-2011) – Outboard Engine
-   Yamaha LF250A, 4.2L V6 (250 HP, 2013-2011) – Outboard Engine
-   Yamaha LF250BTUR, BTXR (250 HP, 2010-2006) – Outboard Engine
-   Yamaha LF250TUR, TXR (250 HP, 2010-2006) – Outboard Engine
-   Yamaha VF250, 4.2L V6 V MAX SHO (250 HP) – Outboard Engine
-   Yamaha VF250X, 4.2L V6 V MAX SHO (250 HP) – Outboard Engine
-   Yamaha F225, 3.3L V6 (225 HP) – Outboard Engine
-   Yamaha F225, 4.2L V6 (225 HP) – Outboard Engine
-   Yamaha F225TLR (225 HP, 2010-2006) – Outboard Engine

That is the 25 most common of 98 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: 4704, 5344, 5618, IKH20, IKH20TT, VKH20
-   Bosch: 9613, 9615, FR7N1133X
-   ACDelco: 12565996
-   Champion: 9775

## 📦 Condition

-   Brand new genuine product
-   Supplied in original packaging

## Details

- **Price:** 34.0 AUD
- **Vendor:** NGK
- **Type:** Ignition & Controls

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 34.00 AUD | In stock |

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/lfr6aix-11-ngk-iridium-spark-plug-genuine-ngk-spark-plug)
> Updated: 2026-09-03