Champion L77JC4 Spark Plugs

The Champion L77JC4, stock number 821, is a 14mm marine plug with a cut back ground electrode. The cut back ground exposes more of the spark to the incoming charge, which helps ignitability in a two stroke that is running rich or cold, and it is the reason this plug shows up across a wide span of outboard horsepower.

• Non-resistor plug. Fit it only where the engine builder specifies a non-resistor type; resistor and non-resistor plugs are not freely interchangeable.
• Gap: 0.039 in (1.0mm).
• 14mm thread, 13/16 in hex, 1/2 in reach, gasket seat, solid terminal.
• Cut back nickel ground electrode with a copper core center electrode.
• Resists fouling and holds heat range under load.

Verify against the engine manual before you fit it. Heat range numbers do not translate between plug manufacturers, and a Champion 77 is not comparable to an NGK 7.