NGK B7HS-10 - Plug Gap 0.9 mm/0.035 inFits 6 ('86 - '00), 8 ('86 - '04), Fits 9.9/15 ('84 - '04), 20 ('96 - '97), 25 ('84 - '04 2 cyl.), 25 ('96 - '02 3 cyl.), 30 ('87 - '02 3 cyl.), 40 ('84 - '04), C40 ('97 - '02 3 cyl.)
The 1998 model, Yamaha 250 hp outboard, requires an NGK BR9HS-10 spark plug, gapped to .039 in.
The Yamaha Pro 50 outboard requires an NGK BR8HS-10 plug, gapped to .039in.
The spark plug gap for most Yamaha outboards is around .030 - 0.035in.
The recommended spark plug gap (per NGK) is .039"
.35
The 1998 model, 115 hp Yamaha outboard, requires an NGK BR8HS-10 spark plug, gapped to .039 in.
you have to make ngk b8hs-10
.04 inch
0.6 - 0.7mm (0.024-0.028 inches)
Spark plug gap on this engine is .030
gap should be 0.9mm (0.035") N.
The 2004 Viper Yamaha spark plug gap is .018. Most spark plugs will be pre-gapped by the spark plug manufacturer.