Bombardier SeaDoo 1992 factory shop manual, Page 166Get this manual
Section 07 ELECTRICAL Sub-section 07 (SPARK PLUGS)
DESIGN SYMBOLS USED ON NGK SPARK PLUGS
First letter prefix for thread and hexagon size Second and third letter prefix Heat rating number for construction feature, except single prefix
First letter suffix for thread reach
Second letter suffix for construction feature, etc
Constructionfuture
Thread reach
ConBtructmn featureate
-1exagon size 20 mm
-1exagor size 16.0 mrn
lthreadi dia I8 mmli
specials
Special plug tor Hoflda vehicles
ompetion type Racing plugs, center electrode of nickel alloy Racing plugs center electrode off precious metal Racing plugs nickel
10 mm 12 mm
Hexagon size 23 mm