Champion QL86C Marine Spark Plug 933M - Fits Yamaha F2.5, F8, F9.9, T8, T9.9 Outboards

The Champion QL86C marine spark plug (Champion Spark Plug # 933M) is a quality OEM-replacement plug built for the demands of outboard engine operation. It uses a copper core center electrode that increases conductivity and improves heat control, helping the plug wear evenly over its service life instead of degrading unevenly under sustained load. The copper core design also gives the plug superior corrosion resistance and helps it resist fouling, both common failure points for spark plugs that run in humid marine environments and see frequent heat cycling.

This plug is engineered for dependable, proven performance under heavy engine loads and heat, and is intended as a direct replacement in outboard motors that specify the QL86C / 933M plug. It is a straightforward drop-in maintenance part for routine tune-ups or as a replacement when an existing plug is fouled, worn, or misfiring. Buyers replacing plugs on compatible Yamaha outboards can order this part with confidence that it matches the original electrode design and heat range.

Specifications

• Brand: Champion
• Manufacturer Part Number: CCH933M
• Champion Product Code: QL86C
• Champion Spark Plug Number: 933M
• UPC: 037551005260
• Core Material: Copper
• Thread Size: 14 millimeters
• Weight: 0.15 pounds
• Compatible Engines: Yamaha F2.5, F8, F9.9, T8, T9.9 outboards
• Key Features: Resists fouling, superior corrosion resistance, increased conductivity and heat control

Fitment

• Yamaha F2.5, 1 cylinder, 4-Stroke, 2.5 HP
• Yamaha F8, 2 cylinder, L2 4-Stroke, 8 HP, 197cc
• Yamaha F9.9, 2 cylinder, L2 4-Stroke, 9.9 HP, 212cc
• Yamaha T8, 2 cylinder, L2 4-Stroke, 8 HP, 197cc
• Yamaha T9.9, 2 cylinder, L2 4-Stroke, 9.9 HP, 212cc

Replaces (OEM)

• Bombardier 503953
• Bombardier 437682
• Bombardier 503949

Frequently Asked Questions

What engines does the Champion QL86C (933M) spark plug fit? This plug fits Yamaha F2.5 (1 cylinder, 4-Stroke, 2.5 HP), F8 and T8 (2 cylinder, L2 4-Stroke, 8 HP, 197cc), and F9.9 and T9.9 (2 cylinder, L2 4-Stroke, 9.9 HP, 212cc) outboards.

Is the QL86C a genuine OEM part or an aftermarket equivalent? The Champion QL86C, also identified as Champion 933M, is manufactured by Champion as a quality OEM-replacement spark plug, not a generic aftermarket clone.

What OEM numbers does the Champion 933M cross reference to? It cross-references to Bombardier part numbers 503953, 437682, and 503949, so any of those OEM numbers can be used to confirm this is the correct plug.

What is the electrode material in this spark plug? The Champion QL86C uses a copper core center electrode, which increases conductivity and gives more precise control over heat range for longer plug life.

What thread size does the Champion 933M spark plug use? This spark plug has a 14 millimeter thread size.

How much does the Champion QL86C spark plug weigh? The Champion QL86C (part CCH933M / 933M) weighs 0.15 pounds.

Does this plug resist fouling in marine use? Yes, the copper core design in the Champion 933M is built to resist fouling and provide superior corrosion resistance, which matters in the humid, heat-cycling conditions outboard engines run in.

Can this spark plug handle heavy engine loads without overheating? Champion designed the QL86C marine spark plug to resist overheating under heavy engine loads while maintaining dependable, proven performance.

How many spark plugs come in one order? Each order of the Champion QL86C (933M) is for a single spark plug.

Will this plug work in a Yamaha F9.9 outboard? Yes, the Champion 933M/QL86C is specified for the Yamaha F9.9, a 2 cylinder, L2 4-Stroke, 9.9 HP, 212cc engine.

What is the difference between the QL86C and other Champion marine plugs like the QL82YC? The QL86C (Champion 933M) and QL82YC (Champion 932M) are different Champion marine spark plug part numbers built for different outboard applications, so they are not interchangeable without confirming your engine's specified plug number.