Spark Plug
Champion RC12YC
12 compatible models
The Champion RC12YC is an aftermarket spark plug compatible with 12 models across 2 brands. It is a direct cross-reference for OEM part numbers 491055S, 796112S, 98079-56846. Compatible equipment includes Briggs & Stratton 450e Series, Briggs & Stratton 500e Series, Briggs & Stratton 550ex Series, Briggs & Stratton 625ex Series, Briggs & Stratton 675ex Series, and 7 more.
Verify before ordering: Fitment can vary by serial number, production date, region, and sub-model. Match the OEM number and physical dimensions before ordering.
Amazon Buying Check
Use the Amazon listing to compare kit contents, seller details, shipping, and OEM compatibility notes before ordering.
Some links may be affiliate links. Match the OEM number, dimensions, and model variant before buying.
Compatible Models
| Brand | Model | OEM # | Confidence | Source | Reviewed | Evidence | |
|---|---|---|---|---|---|---|---|
| Briggs & Stratton | 450e Series | 491055S | Medium | Aftermarket catalog | 2026-05-21 | 0.030 inch gap | Small Engine |
| Briggs & Stratton | 500e Series | 796112S | Medium | Aftermarket catalog | 2026-05-21 | 0.030" gap | Small Engine |
| Briggs & Stratton | 550ex Series | 796112S | Medium | Aftermarket catalog | 2026-05-20 | 0.030" gap | Small Engine |
| Briggs & Stratton | 625ex Series | 796112S | Medium | Aftermarket catalog | 2026-05-20 | 0.030" gap | Small Engine |
| Briggs & Stratton | 675ex Series | 796112S | Medium | Aftermarket catalog | 2026-05-20 | 0.030" gap | Small Engine |
| Briggs & Stratton | 725EXi Series | 796112S | Medium | Aftermarket catalog | 2026-05-20 | 0.030" gap | Small Engine |
| Briggs & Stratton | 850EXi Series | 796112S | Medium | Aftermarket catalog | 2026-05-20 | 0.030" gap | Small Engine |
| Honda | GX160 | 98079-56846 | Medium | Aftermarket catalog | 2026-05-20 | 0.7mm plug gap | Small Engine |
| Honda | GX200 | 98079-56846 | Medium | Aftermarket catalog | 2026-05-21 | 0.7mm gap | Small Engine |
| Honda | GX270 | 98079-56846 | Medium | Aftermarket catalog | 2026-05-20 | 0.7mm gap | Small Engine |
| Honda | GX340 | 98079-56846 | Medium | Aftermarket catalog | 2026-05-20 | 0.7mm gap | Small Engine |
| Honda | GX390 | 98079-56846 | Medium | Aftermarket catalog | 2026-05-20 | 0.7mm gap | Small Engine |
What this part is
Champion RC12YC is listed here as a spark plug replacement option. Use this page as a fitment cross-reference, then confirm the removed part, model plate, and seller listing details before buying.
OEM numbers it replaces
491055S, 796112S, 98079-56846
Alternate spellings
RC12YC is the normalized part number used on this site.
Known exclusions
- No specific exclusion is listed in the current data. Still verify serial range, production variant, and removed-part details before ordering.
Dimensions and specs
- 0.030 inch gap
- 0.030" gap
- 0.7mm plug gap
- 0.7mm gap
Symptoms that suggest replacement
- Won't start
- Hard hot restart
- Rough idle
- Fuel-fouled or carbon-heavy plug
How to verify before buying
- Confirm your equipment is one of the compatible models listed above.
- Match the OEM number, stamped part number, or physical spec against the removed part.
- Read the model-specific evidence, confidence, source, reviewed date, dimensions, notes, and exclusions before opening an Amazon listing.
Common wrong-fit mistakes
- Ordering from a broad model-family listing without checking the exact equipment model.
- Ignoring the old OEM number, stamped part number, or physical dimensions.
- Matching the plug number but missing the required gap, terminal style, or thread reach.
Related model and part pages
Briggs & Stratton 450e Series spark plugBriggs & Stratton 500e Series spark plugBriggs & Stratton 550ex Series spark plugBriggs & Stratton 625ex Series spark plugBriggs & Stratton 675ex Series spark plugBriggs & Stratton 725EXi Series spark plugBriggs & Stratton 850EXi Series spark plugHonda GX160 spark plugNGK BPR5ES spark plugChampion CJ8Y spark plugNGK BPM8Y spark plugNGK BPMR8Y spark plugChampion RS12YC spark plugNGK BPR6ES spark plug
Related Repair Guides
Where to Find the Model Number on Echo TrimmersHow to identify an Echo trimmer model before ordering carburetors, filters, primer bulbs, fuel lines, or trimmer heads.Honda GX160 Annual Maintenance PartsA seasonal maintenance checklist for Honda GX160 engines with links to common spark plug, air filter, and carburetor lookup pages.Briggs 450e Won't Prime or Stay RunningA push-mower troubleshooting guide for Briggs & Stratton 450e engines with primer, fuel filter, air filter, carburetor, and spark plug lookup steps.How to Measure Chainsaw Chain Pitch, Gauge, and Drive LinksA model-identification guide for chainsaw chain replacement, explaining why bar length alone is not enough.
Amazon buying cautions
- Check that the Amazon listing includes the exact part number or verified cross-reference shown here.
- Compare kit contents, gaskets, fuel lines, bulbs, plugs, filters, and dimensions against the removed part before checkout.
- A listing title can mention the right model and still include the wrong revision, accessory, or generic substitute.