Osculati 47.558.87 – NGK ITR4A15 Iridium Marine Spark Plug
The NGK ITR4A15 (Osculati 47.558.87) is a high-performance marine spark plug equipped with an iridium center electrode, providing ultra-fine spark precision and enhanced durability. With a factory-set gap of 1.5 mm and projected tip design, it is particularly suited for modern 4-stroke outboards using electronic fuel injection and advanced ignition control systems.
Key Features:
- Iridium center electrode – high melting point and superior longevity
- 1.5 mm spark gap – promotes efficient ignition in lean-burn EFI systems
- Built-in resistor – prevents EMI interference with marine electronics
- Projected insulator tip – improves fuel burn and throttle response
- Engineered for 4-stroke EFI and high-compression outboard engines
Technical Specifications:
| Attribute | Value |
|---|---|
| Model | NGK ITR4A15 |
| Osculati Code | 47.558.87 |
| Thread Diameter | M14 × 1.25 mm |
| Reach | 19 mm |
| Hex Size | 16 mm |
| Heat Range | 4 (warm) |
| Gap | 1.5 mm |
| Electrode Type | Iridium center, projected tip |
| Resistor | Yes |
Manufacturer Compatibility:
- Yamaha
- Suzuki
- Mercury
- Honda
- Tohatsu
- Selva
- Mariner
Cross Reference:
| Brand | Model |
|---|---|
| NGK | ITR4A15 |
| Champion | – |
The NGK ITR4A15 is ideal for marine engine applications where precision ignition and extended plug life are critical. It is especially recommended for modern 4-stroke outboards with EFI, providing optimal spark efficiency and corrosion resistance in harsh saltwater environments.
