Yamaha EF7000 Service Manual page 137

Remove the spark plug and attach it to the spark
plug cap, and then ground the spark plug to check
for spark.
GOOD SPARK
Check the carburetor for clogged passages or fuel
overflow.
GOOD
Check the compression pressure.
OUT OF
SPECIFICATION
Measure the valve clearance.
GOOD
Check the valve face and valve seat for wear.
GOOD
WEAK OR NO SPARK
9 Check the spark plug for dirt and check the
spark plug gap.
9 Check for the voltage leakage due to faulty con-
nection or broken insulation of the high tension
cord.
9 Check the TCI unit connector for corrosion or
faulty connection.
9 Check the ignition system. (Refer to "IGNITION
SYSTEM" on 5-29)
GOOD
Install a substitute TCI unit to check spark condi-
tions.
GOOD
NOT GOOD
GOOD
OUT OF
SPECIFICATION
WORN
6-2
ENGINE
NOT GOOD
Clean or replace.
NOT GOOD
Replace the TCI unit.
Resurface or replace.
TRBL
Clean.
Adjust.
6