Osculati 47.558.81 – NGK B8S Marine Spark Plug
The NGK B8S (Osculati 47.558.81) is a cold-range, non-resistor spark plug made for classic 2-stroke outboards and older marine engines without electronic ignition systems. It provides reliable spark in high-temperature applications, making it ideal for engines operating at sustained high RPM. The simple, non-resistor construction offers maximum voltage delivery for robust ignition in older magneto or CDI systems.
Key Features:
- Cold heat range (8) prevents pre-ignition in hot-running 2-stroke engines
- Non-resistor design ensures full spark energy transfer
- Short 12.7 mm reach ideal for compact combustion chambers
- Durable nickel alloy electrode resists wear and corrosion
- Designed for legacy and high-performance 2-stroke outboard engines
Technical Specifications:
| Attribute | Value |
|---|---|
| Model | NGK B8S |
| Osculati Code | 47.558.81 |
| Thread Diameter | M14 × 1.25 mm |
| Reach | 12.7 mm |
| Hex Size | 20.8 mm |
| Heat Range | 8 (cold) |
| Gap | 0.7 mm |
| Electrode Type | Standard |
| Resistor | No |
Manufacturer Compatibility:
- Yamaha
- Mercury
- Mariner
- Suzuki
- Honda
- Tohatsu
- Selva
Cross Reference:
| Brand | Model |
|---|---|
| NGK | B8S |
| Champion | – |
The NGK B8S is an excellent spark plug choice for traditional 2-stroke marine engines that require a cold plug without modern resistor protection. It delivers full spark intensity and durability in engines running at high loads, making it a favorite among vintage outboard technicians and performance tuners.
