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Marine & Outboard Spark Plugs

Champion Spark Plug L78V (833M) (BUHW-2)

SKU: GB-L78V

$30.80
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The Champion L78V is a non-resistor surface-gap spark plug designed primarily for selected high-performance 2-stroke outboard motors. Its surface-gap electrode configuration has no conventional projecting ground electrode, helping resist fouling and withstand demanding high-speed marine operation. L78V is used in selected older Mercury, Mariner, Johnson and Evinrude outboards where this specific surface-gap plug is specified.

Key benefits

Key Benefits

  • - Surface-gap electrode design
  • - Designed for demanding 2-stroke marine applications
  • - No conventional projecting ground electrode
  • - Helps resist fouling in high-performance 2-stroke engines
  • - Non-resistor construction
  • - Compact 14 mm thread
  • - Short-reach design
  • - No conventional adjustable electrode gap
  • - Commonly used in selected older Mercury/Mariner and OMC outboards

Specifications & Dimensions

  • - Brand: Champion
  • - Part Number: L78V
  • - Spark Plug Type: Surface-gap
  • - Thread Diameter: 14 mm / 0.551"
  • - Thread Size: M14 × 1.25
  • - Thread Pitch: 1.25 mm / 0.049"
  • - Thread Reach: 12.7 mm / 0.500"
  • - Hex / Spanner Size: 20.8 mm / 13/16"
  • - Seat Type: Flat / gasket seat
  • - Resistor: No
  • - Electrode Type: Surface gap
  • - Conventional Ground Electrode: None
  • - Adjustable Spark Gap: No
  • - Sealing Washer: Yes
  • - Application: Primarily 2-stroke marine/outboard engines
  • Compatible Outboard Motors

Mercury Outboards

  • - Mercury 35 HP
  • - Mercury 40 HP
  • - Mercury 45 HP
  • - Mercury 50 HP
  • - Mercury 60 HP
  • - Mercury 65 HP
  • - Mercury 70 HP
  • - Mercury 75 HP
  • - Mercury 80 HP
  • - Mercury 85 HP
  • - Mercury 90 HP
  • - Mercury 100 HP
  • - Mercury 115 HP
  • - Mercury 125 HP
  • - Mercury 135 HP
  • - Mercury 140 HP
  • - Mercury 150 HP
  • - Mercury 175 HP
  • - Mercury 200 HP
  • Exact compatibility depends heavily on model year, serial number and ignition system, because Mercury used several different surface-gap plugs across these engine families.

Mariner Outboards

  • - Mariner 40 HP
  • - Mariner 50 HP
  • - Mariner 60 HP
  • - Mariner 70 HP
  • - Mariner 75 HP
  • - Mariner 80 HP
  • - Mariner 90 HP
  • - Mariner 115 HP
  • - Mariner 135 HP
  • - Mariner 150 HP
  • - Mariner 175 HP
  • - Mariner 200 HP
  • Mercury-built Mariner models are the principal applications; Yamaha-built Mariner models can specify different plugs.

Johnson Outboards

  • - Johnson 85 HP
  • - Johnson 90 HP
  • - Johnson 100 HP
  • - Johnson 115 HP
  • - Johnson 120 HP
  • - Johnson 125 HP
  • - Johnson 135 HP
  • - Johnson 140 HP
  • - Johnson 150 HP
  • - Johnson 175 HP
  • - Johnson 200 HP
  • - Johnson 235 HP
  • Fitment varies by year and ignition system.

Evinrude Outboards

  • - Evinrude 85 HP
  • - Evinrude 90 HP
  • - Evinrude 100 HP
  • - Evinrude 115 HP
  • - Evinrude 120 HP
  • - Evinrude 125 HP
  • - Evinrude 135 HP
  • - Evinrude 140 HP
  • - Evinrude 150 HP
  • - Evinrude 175 HP
  • - Evinrude 200 HP
  • - Evinrude 235 HP
  • For Johnson/Evinrude engines in particular, the model year must be checked, because many later applications changed to Champion QL-series resistor plugs.

Cross-Reference Spark Plugs

  • - Champion: L78V
  • - NGK: BUHW
  • - NGK: BUHW-2 – for selected applications only

Important Fitment Information

  • The L78V is a surface-gap plug. Unlike conventional spark plugs, it does not have a projecting side/ground electrode that is manually bent to set a gap.
  • Therefore
  • - Do not attempt to gap an L78V like a conventional spark plug.
  • - Confirm the engine model, year and serial number before installation.
  • - Do not substitute a conventional J-gap plug solely because its thread dimensions match.
  • - Check whether the engine specifies L78V, L76V, L77JC4, QL77JC4, BUHW, BUHW-2 or another plug, as these are not universally interchangeable.

Signs the Spark Plug Needs Replacing

  • - Difficult starting
  • - Engine misfiring
  • - Poor high-speed performance
  • - Hesitation during acceleration
  • - Reduced engine power
  • - Excessive carbon fouling
  • - Oil contamination
  • - Corrosion
  • - Damaged insulator
  • - Worn or damaged surface-gap electrode area

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