Spark Plug - Yamaha 40V Service Manual

INSP
ADJ
GENERAL
NOTE:
Batteries vary
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.
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
2. Clean:
Spark plug
Clean the spark plug with a plug
cleaner or wire brush.
3. Inspect:
Spark plug type
Standard spark plug:
40hp: B7HS-10
For CANADA and Europe:
50hp: B8HS-10
For CANADA and Europe:
3-10
among manufacturers.
BR7HS-10
BR8HS-10
E