NGK CR5EH-9 6689 Spark Plug Honda BF8D BF9.9D BF15D BF20D Outboard
CR5EH-9-NGK
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NGK CR5EH-9 Spark Plug for Honda Outboards
NGK Standard Nickel Spark Plug | CR5EH-9 / 6689
Genuine NGK CR5EH-9 resistor spark plug for selected Honda small four-stroke outboards. It uses a 10 mm gasket-seat shell, 19 mm reach and 0.9 mm nominal gap, with NGK heat range 5.
Key Features
- ✔ Standard nickel centre electrode
- ✔ Internal resistor helps suppress electrical interference
- ✔ 10 mm × 1.0 thread
- ✔ 19 mm reach with gasket seat
- ✔ 0.9 mm suffix gap
- ✔ NGK heat range 5
Technical Specs
| NGK code | CR5EH-9 |
| NGK stock number | 6689 |
| Thread | 10 mm × 1.0 |
| Reach | 19 mm / 3/4 in |
| Hex | 16 mm / 5/8 in |
| Seat | Gasket |
| Nominal gap | 0.9 mm / 0.035 in |
| Heat range | 5 |
| Resistor | Yes |
Compatibility / Fitment Guide
Verified Honda families: selected BF8D and BFP8D 8 HP, BF9.9D, BF15D and BF20D two-cylinder four-stroke outboards. NGK’s part finder specifically lists CR5EH-9 for BF20D applications.
Production differences: Honda application charts can specify a different service gap by year even with the same plug code. Check the owner’s manual for the full model code and serial range.
Exclusions: CR6EH-9 is one heat range colder; CPR6EA-9 has a different projected firing end. Do not substitute on the basis of 10 mm thread and 19 mm reach alone.
Part Number Cross Reference
| NGK part | CR5EH-9 |
| NGK stock | 6689 |
| Honda references | 98059-55916 / 98059-55926 |
| Denso equivalent | U16FER-9 (verify engine manual) |
| 4Boats SKU | CR5EH-9-NGK |
Cross-reference numbers identify applications; always confirm the engine model, serial range and plug specification before substitution.
Frequently Asked Questions
Will it fit a Honda BF20D?
Yes, CR5EH-9 is a verified BF20D plug, but confirm the model/serial and service gap.
Does a two-cylinder Honda need two plugs?
Normally yes, but this listing supplies one plug.
Can I use CR6EH-9?
Only if the exact Honda manual lists it; heat range differs.
Is the Honda box included?
This is an NGK-branded plug; Honda references are cross-references, not a claim of Honda retail packaging.
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.
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