NGK B8HS-10 Spark Plug

The NGK B8HS-10, stock number 5126, is a standard nickel plug with no resistor and a factory preset gap. Read that first part carefully: this is a non-resistor plug, and resistor and non-resistor plugs are not freely interchangeable. Fit it where the engine builder calls for a non-resistor type and nowhere else.

• Preset gap: 0.039 in (1.0mm), which is what the -10 suffix means in NGK's numbering.
• Non-resistor. The absence of an R in the part number is the tell.
• 14mm thread, 13/16 in hex, 1/2 in reach, gasket seat.
• Removable nut terminal.
• Solid copper core for heat dissipation and a broad heat range, with corrosion-resistant plating.
• Interchanges with Johnson/Evinrude 0503705 and Yamaha B8H-S1000-00-00.

Check the engine manual before fitting. NGK heat ranges climb as the plug gets colder, the reverse of the Champion scale.