Yamaha Marine Outboards F4A/F4 Factory Service Manual, Page 68Get this manual

INSP ADJ
CONTROL SYSTEM
Measurement steps: Start the engine and allow it to warm up for few minutes8 Attach the tachometer to the spark plug lead of cylinderTachometer: YU-08036-A

2Adjust:

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