A champion RC12YC spark plug is 14mm thread diameter. The torque for this size is 18-22 foot-pounds (25 to 30Neuton·meters)
GAP .030"
Champion 3071
RC12YC in Champion
Rc12yc
champion rc12yc
Rc12yc
Champion Rc12yc...Denso Q16pru-11...NKG BKR4E
champion RC12YC of ngk BKR5E-11
Champion RC12YC, NGK BKR5E-11
Should take a Champion: RC12YC
Champion RC12YC
Champion rc12yc, Briggs 491055 or Champion Premium plug (platinum) #3071