Service Manual

Table Of Contents
Greensmaster Flex 18/21Page 3 – 6Engine
Spark Plug
Use a NGK BPR 5ES spark plug or equivalent.
1. Make sure engine is OFF. Carefully pull spark plug
wire off the spark plug.
2. Clean around spark plug and remove plug from the
cylinder head.
NOTE: The condition of the spark plug can give an ac-
curate picture of the overall condition of the engine. Use
the chart on the following page as a guide to determine
possible problems with the engine.
3. Inspect the spark plug.
IMPORTANT: Replace a cracked, fouled or dirty
spark plug. Do not sand blast, scrape or clean spark
plug electrodes because engine damage could re-
sult from grit entering cylinder.
4. Set electrode gap from 0.028” to 0.032” (0.7 to 0.8
mm). Install correctly gapped spark plug into cylinder
head and torque plug to 17 ft–lb (23 N–m). Connect
spark plug wire to spark plug.
Figure 4
0.028” to 0.032“
(0.7 to 0.8 mm)