Service manual

G420F(FE) Service Manual Chapter 2. Recommended Maintenance 27
5. Install the spark plug and tighten it to the specified
torque.
Take care not to over tighten it to prevent cylinder
head threads from damage.
Tightening torque 2~3kg·m
SPARK PLUG ANALYSIS
State
Contact point is
black
Contact point is
white
Description
• Density of the
fuel mixture is
thick
• Density of the
fuel mixture is thin
• Lack of air
intake
• Ignition timing is
fast
• Spark plug is
tight
• Lack of torque