4551 (BR9HS-10) NGK Standard spark plugs are OE approved and recommended for reliable performance for most applications. NGK Standard spark plugs feature a 5-Rib insulator design to prevent flashover and are also treated to ensure ease of installation and removal. Cold rolled threads prevent damage to cylinder head. NGK's triple gasket sealing process virtually eliminates gas leakage past the shell. Solid Copper Core provides superior heat dissipation, conductivity and a broader heat range.

These spark plugs are compatible with Mercury:
7.5 HP 75; L2 7.5 HP (1985–1989)
9.8 HP 9.8; L2 9.8 HP (1985–1989)
These spark plugs are compatible with Yamaha:
130 HP 130; V4 130 HP (2004–2008)
130 HP L130; V4 130 HP (2001–1989)
130 HP S130; V4 130 HP (1999–1988)
200 HP P200; 3.1L V6 200 HP (1995–1991)
225 HP 225 Excel; 2.6L V6 225 HP (1995–1987)
225 HP 225; 2.6L V6 225 HP (1995–1987)
225 HP X225; 3.1L V6 225 HP (1999–1994)
225 HP L225; 3.1L V6 225 HP (1999–1994)
225 HP LX225; 3.1L V6 225 HP (1999–1997)
225 HP S225; 3.1L V6 225 HP (1999–1994)
225 HP SX225; 3.1L V6 225 HP (1999–1997)
225 HP V225; 3.1L V6 225 HP (2001–1997)
225 HP V6 Excel; 2.6L V6 225 HP (1989–1987)
225 HP VX225; 3.1L V6 225 HP (2004–1997)
250 HP L250; 3.1L V6 250 HP (1999–1997)
250 HP LX250; 3.1L V6 250 HP (1999–1997)
250 HP S250; 3.1L V6 250 HP (1999–1997)
250 HP SX250; 3.1L V6 250 HP (2003–1997)
250 HP VX250; 3.1L V6 250 HP (2004–2002)

Product Specifications:
Stock Number: 4551
Part Number: BR9HS-10
Material Grade: Nickel/Copper
Resistance (Ohms):0
Ground Electrode Tip Design: Standard
Ground Configuration: J-Gap
Ground Electrode Core Material: Nickel
Washer Included: Yes
Electrical Terminal Type: Removable Nut
Center Electrode Core Material: Copper
Center Electrode Tip Material: Nickel
Pre-Gap Size (IN): .040
Pre-Gap Size (MM):0
Ground Electrode Quantity: 1
Hex Size: 13/16"
Insulator Height (IN):14
Insulator Height (MM):3
Manufacturer Heat Range: 9
Seat Type: Flat
Reach (IN):500
Reach (MM):7
Thread Diameter (IN): 551
Thread Diameter (MM):0
Insulator Material: Ceramic
Resistor Type: Yes
Ground Electrode Tip Material: Nickel
Skirt: No
Center Electrode Insulator Tip Projection (IN):04
Center Electrode Insulator Tip Projection (MM):0
Center Electrode Design: Standard
Washer Type: Crush
Center Electrode Projection: Non-Projected
Grade Type: Standard Replacement