2000-2005 Yamaha F40B Outboard Service Manual, Page 154Get this manual

CARBURETOR
CHECKING THE CARBURETOR
Do not use steel wire to clean the jetsThis may enlarge the jet diameters and seriously affect performance1Check: Carburetor body

Cracksdamage Contamination

ReplaceClean

Main jet Pilot jet Main nozzle Contamination Needle valve Grooved wear

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