1998 Yamaha 25J, 30D, 25X, 30X outboards Factory Service Manual, Page 48Get this manual
INSP ADJ
PERIODIC SERVICE
D35000-0
SPARK PLUG
1C eck th electro co ditio and state of ar, ote th insulator color and th electro pN or al co ditio is diu to lig ht ta colorDistinctly differe nt color eck th gin co ditio nW hitish colorLe fu el ixture Plu filter, jet ir le ak ro settin gs Blackish colorElectrical alfu nctio efectiv sp ark plu efectiv ig nitio syste Rich ixture xcessiv idlin g