Yamaha 40V - Spark Plug

3-10
INSP
ADJ
E
GENERAL
NOTE:
● Batteries vary among manufacturers.
Therefore the following procedures may
not always apply. Consult your battery
manufacturer’s instructions.
● Disconnect the black negative lead first to
prevent the risk of shorting.
1. Inspect:
● Battery fluid level
● Battery fluid specific gravity
Spark plug
1. Inspect:
● Electrode 1
Worn/Damaged → Replace.
● Insulator color 2
Distinctly different color → Check the
engine condition.
2. Clean:
● Spark plug
Clean the spark plug with a plug
cleaner or wire brush.
3. Inspect:
● Spark plug type
Color guide:
Normal:
Medium to light tan color
Whitish color: Lean fuel mixture
● Plugged fuel mixture
● Air leak
● Wrong setting
Blackish color:
Electrical malfunction
● Defective spark plug
● Defective ignition system
● Rich mixture
● Excessive idling
Standard spark plug:
40hp: B7HS-10
For CANADA and Europe:
BR7HS-10
50hp: B8HS-10
For CANADA and Europe:
BR8HS-10