Operator's Manual

Replacing the Spark Plug
1. Remove the spark-plug wire.
2. Clean around spark plug and remove plug from cylinder head.
Note: Replace a cracked, fouled, or dirty spark plug. Do not sand blast, scrape, or clean
electrodes because engine damaged could result from grit entering the cylinder.
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3. Set the air gap at 0.70 to 0.80 mm (0.028 to
0.031 inch)
. Install the spark plug carefully
by hand to avoid cross-threading.
4. After the spark plug is seated, tighten it with a
spark plug wrench to compress the sealing
washer.
5. When installing a new spark plug, tighten 1/2
turn after the spark plug seats to compress the washer.
6. When installing the original spark plug, tighten 1/8 to 1/4 turn after the spark plug seats
to compress the washer.
Note: A loose spark plug can overheat and damage the engine. Overtightening the
spark plug can damage the threads in the cylinder head.
7. Connect the spark-plug wire.
Cleaning the Blower Housing
To ensure proper cooling, ensure that the cooling fins and other external surfaces of the
engine are kept clean at all times.
Ensure that the cooling shrouds are installed.
IMPORTANT
Operating the engine with dirty or plugged cooling fins and/or cooling shrouds
removed causes engine damage due to overheating.
3451-705A Page 5–10 Maintenance: Engine Maintenance