BUHW has more copper in the metal.
ngk buhw2 or ngk buhw
NGK BUHW crosses to Champion L76V according to the service manual for my 40hp Force outboard motor.
funny this should pop up i just read about this, it will run with the buhw but they don't fire as hot as the buhw-2 due to a shorter distance for spark to jump, this could lead to premature fouling. if your engine calls for the buhw-2, i would stick with them
The 3 cylinder model Mercury 90, uses a NGK BUHW-2, or Champion L78V. The 6 cylinder model, takes a NGK BUHW, or a Champion L76V.
The 105 hp Chrysler outboard requires an NGK 1966-1967 BR6S 1968-1974 BUHW 1975-1976 BUHX 1976-1983 BUHW
Models from 1970 - 1978 use a NGK BUHW-2. Models from 1979 - 1985 use a NGK B9HS-10, gapped to .040 in.
Current Mercury 2 Stroke 90 HP motors use NGK BUZHW-2 plugs. This is a resistor plug to reduce static interference in the radio. The non-resistor (Lower cost option) is NGK BUHW-2. The difference is about $2/plug hp
They are interchangeable. Difference between the two :ZFR6K-11 is a standard NGK plug where as IZFR6K-11 is the Iridium version.
8 is hotter than 9 (toolmanx3)
Basically they are for different climate/riding conditions.
heat range. 7 is a "hotter" plug. That means it transfers more heat to the cylinder head during operation.
The 1999 model, 90 hp Mercury outboard requires an NGK BUHW-2 spark plug, standard plug wires are acceptable.