NGK BR5HS 3722 Spark Plug Yamaha Mariner 2A 2B 2M 2-Stroke Outboard
BR5HS-NGK
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NGK BR5HS Spark Plug for Yamaha and Mariner 2HP
NGK Standard Nickel Spark Plug | BR5HS / 3722
Genuine NGK BR5HS short-reach resistor spark plug for selected Yamaha-built 2 HP two-stroke outboards sold under Yamaha and Mariner branding. Its 14 mm gasket-seat shell and 12.7 mm reach must match the cylinder head.
Key Features
- ✔ Standard nickel spark plug
- ✔ Resistor suppresses ignition interference
- ✔ Short 12.7 mm reach
- ✔ 14 mm × 1.25 thread with gasket seat
- ✔ NGK heat range 5
- ✔ Sold individually
Technical Specs
| NGK code | BR5HS |
| NGK stock number | 3722 |
| Thread | 14 mm × 1.25 |
| Reach | 12.7 mm / 1/2 in |
| Hex | 20.8 mm / 13/16 in |
| Seat | Gasket |
| Heat range | 5 |
| Resistor | Yes |
| Gap | Set to engine specification |
Compatibility / Fitment Guide
Verified marine applications: Yamaha and Yamaha-built Mariner 2 HP two-stroke models 2A, 2B and 2M where BR5HS is listed. Published model guides commonly identify Yamaha OEM reference 94702-00249-00.
Check the model plate: Mariner engines were sourced from different manufacturers, and “2 HP” alone is not enough. Confirm the model code, ignition specification and the plug removed from the engine.
Exclusions: many 2.5 HP models use BP6HS/BPR6HS, and other small outboards may require BR6HS, BR7HS or a different reach. Never select a spark plug solely by thread diameter.
Part Number Cross Reference
| NGK part | BR5HS |
| NGK stock | 3722 |
| Yamaha reference | 94702-00249-00 / 947020024900 |
| 4Boats SKU | BR5HS-NGK |
Cross-reference numbers identify applications; always confirm the engine model, serial range and plug specification before substitution.
Frequently Asked Questions
Does it fit every Yamaha 2 HP?
It fits the verified 2A/2B/2M families where BR5HS is specified; confirm the model plate.
Will it fit a Mariner 2.5 HP?
Not automatically. Many 2.5 HP engines specify a projected BP6HS/BPR6HS type.
Is the gap pre-set?
It is supplied to NGK production specification, but check and set the gap required by the exact engine.
Is this a resistor plug?
Yes. The R in BR5HS denotes an internal resistor.
Fit only the plug specified by the engine manufacturer. Check the gap before installation and use the torque stated for the engine’s cylinder-head material and service condition.
For the products under £150 the shipping is £6.99.
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