NGK Spark Plugs CR9EB 8-Pack for Yamaha Jet Boats (2003–2015) — Copper Core, 0.750 in Reach

NGK 6955 (CR9EB) is an 8-pack of OEM-grade nickel/copper standard spark plugs designed to replace factory plugs in select Yamaha jet boats from 2003–2015.

These NGK Standard plugs pair a high-purity copper core with a nickel-alloy firing tip and a durable alumina-silicate ceramic insulator to match original equipment specifications for many Yamaha inboard/outboard and jet-ski motor applications. Each plug includes a crush washer, a 0.032 in (0.8 mm) pre-gap, 5,000 ohm resistor, and a flat-seat design with 0.750 in (19.0 mm) reach—features intended to maintain reliable ignition, heat control, and fitment for the listed models.

Which Yamaha models and years will these NGK CR9EB plugs fit?

These plugs are compatible with a range of Yamaha jet boat and sport boat engines produced between 2003 and 2015. Fitment covers many AR, SX, SR and SXT model designations with 1000–1100+ cc engines; always confirm part CR9EB (stock number 6955) against your owner’s manual or engine tag before ordering.

• Common fits include AR210, SX210, 212SS, 212X, SR230 and AR230 model years listed in the product data.
• Coverage spans FAT1100, FRT1100, LAT1100, SRT1000 and SRT1100 engine codes shown in the description.
• Check thread diameter 10.0 mm, reach 19.0 mm, and flat-seat type to confirm compatibility.

How does the construction affect performance and longevity?

NGK Standard plugs use a solid 98% pure copper core for strong conductivity and heat dissipation, paired with a nickel tip and single ground electrode. The alumina-silicate ceramic insulator improves dielectric strength and thermal resistance, while the 5,000-ohm resistor reduces radio frequency interference for electronics on board.

• Copper core improves heat transfer and electrical conduction.
• Nickel tip and single J-gap ground electrode provide dependable spark characteristics.
• Triple gasket sealing and crush washer minimize combustion leakage.

What installation details and measurements should I know?

These CR9EB plugs have a 5/8" (16 mm) hex size for standard spark plug sockets and a thread diameter of 0.394" (10 mm). The specified reach of 0.750" (19.0 mm) and flat seat require matching the engine’s factory seat and thread length to avoid mechanical or sealing issues.

• Pre-gap set to 0.032 in (0.8 mm); verify and re-gap only if needed per manufacturer specs.
• Insulator height: 2.00 in (50.8 mm); center electrode tip projection 0.02 in (0.5 mm).
• Non-removable nut terminal and crush washer included for proper sealing and installation torque control.

Why choose NGK Standard plugs instead of aftermarket alternatives?

NGK Standard plugs are engineered to meet original equipment tolerances and are widely supplied to OEMs worldwide, offering predictable heat ranges and build quality for routine maintenance intervals. They provide a cost-effective option when OE-spec performance and reliable replacement fitment are the priority.

• OE-level design, materials, and packaging from a leading original equipment supplier.
• Proven ceramic insulator and copper-core construction for steady thermal behavior.
• Backed by NGK customer support for fitment and application questions.

Who is this for? Boaters, marine technicians, and DIY owners who need an OEM-style, budget-friendly spark plug replacement for compatible Yamaha jet boats will find the NGK 6955 CR9EB 8-pack a straightforward, reliable choice. If your engine manual lists CR9EB or NGK 6955 and you require consistent fit, correct heat range (manufacturer heat range 9), and standard replacement performance, these plugs are built to meet those expectations.