2000-2005 Yamaha F40B Outboard Service Manual, Page 122Get this manual

1f.ilI_G_E_N_E_R_A_L _C E_= 3Measure: Spark plug gap Out of specification Regap
Spark plug gap 0.9-1.0 mm (0.035-0.039 in)
4Tighten:

• ATV
• Jet Ski
• Outboard Motors
• Personal Watercraft
• Snowmobiles
• Stern Drives