Indmar Marine Spark Plugs – Set of 8 | LS1 / LQ9 / LY6 / L96 / LS3 Engines | Part #491012

Keep your Indmar LS-series engine firing cleanly and consistently with this genuine Indmar spark plug, covering the LS1, LQ9, LY6, L96, and LS3 engine families. The LS-series engines are among the most respected and reliable marine powerplants ever built — and keeping the ignition system in top condition is the key to maintaining their legendary performance and longevity on the water.

Compatible with: Indmar LS1, LQ9, LY6, L96, and LS3 marine engines fitted to Malibu, Moomba, Supra, and Tige boats. Contact us to verify fitment for your specific model year before ordering.

Which engine do I have?
The LS-series covers several engine variants commonly fitted to Indmar powered wake boats. Here is a quick identification guide:

LS1 — The original Generation III small block V8. Lightweight aluminium block and heads delivering strong performance in a compact package. One of the most popular Indmar engines fitted to wake boats from the late 1990s through mid 2000s.

LQ9 — The high output 6.0L iron block V8, delivering increased torque over the LS1. Popular in heavier wake boats requiring stronger low end pulling power for large crews and heavy ballast loads.

LY6 — The 6.0L Vortec V8 in a flex fuel capable configuration. Strong torque output and proven reliability across a wide range of operating conditions.

L96 — The 6.0L V8 in a natural gas compatible configuration, delivering strong performance with broad fuel flexibility. Known for exceptional durability and long service life.

LS3 — The high performance 6.2L aluminium V8. The most powerful of the LS-series family — delivering the strongest power output and rev capability of the group. A favourite in performance wake sport applications.

If you are unsure which LS-series engine your boat is fitted with — check your engine serial number or contact us and we will confirm the correct plug before you order.

How many spark plugs does my LS-series engine need?
All LS-series engines are V8 configurations requiring 8 spark plugs per engine. Always replace all 8 plugs at the same time — never replace individual plugs unless diagnosing a specific fault. Uneven plug condition across cylinders causes rough running, misfires, and reduced performance. Order quantity 8 before checkout.

What does a spark plug do?
The spark plug delivers the high voltage electrical spark that ignites the compressed air/fuel mixture in each cylinder. Every single power stroke begins with a spark plug firing correctly. A worn or fouled plug causes:

• Incomplete combustion — wasting fuel and reducing power
• Misfires — rough running and vibration under load
• Hard starting — especially after winter storage
• Increased fuel consumption on the water
• Increased load on the ignition coils — accelerating wear

How often should you replace them?
Replace your spark plugs every season or every 100 hours of operation as part of your annual pre-season service. LS-series marine engines work hard under sustained high RPM wake sport conditions — plug wear accelerates significantly faster than in automotive applications.

Signs your spark plugs need replacing:

• Rough idle or misfiring under load
• Hard starting especially after winter storage
• Noticeable drop in fuel economy on the water
• Engine hesitation or stumbling under acceleration
• Uneven power delivery or vibration at cruise RPM
• Approaching recommended replacement interval

Pro tip: The LS-series engines use a coil-on-plug ignition system — each cylinder has its own individual ignition coil sitting directly on top of the spark plug. When replacing plugs always inspect each coil boot for cracking, carbon tracking, or heat damage at the same time. A damaged coil boot causes the same symptoms as a fouled plug and is easily missed if not inspected during the plug change.

Pairs perfectly with:

• 636127 – Water/Fuel Separator Filter
• 556003 – Fuel Filter EFI All Models
• 685007 – Raw Water Pump Impeller
• 872023 – Oil Filter GM 5.7L, 8.1L & 3CSE Special

Features:

• Genuine Indmar OEM specification spark plugs
• Covers LS1, LQ9, LY6, L96, and LS3 marine engine families
• Correct heat range for LS-series marine engine applications
• OEM electrode gap specification for reliable ignition
• Direct replacement — no modifications needed

Part Number: 491012
In stock and shipped fast from Australia 🇦🇺