Honda EU10i Owner's Manual page 45

3.SPARK PLUG SERVICE
RECOMMENDED SPARK PLUG: LR4C-E (NGK)
To ensure proper engine operation, the spark plug must be properly
gapped and free of deposits.
1.Remove the spark plug maintenance cover.
2.Remove the spark plug cap.
3.Clean any dirt from around the spark plug base.
4.Use a spark plug wrench to remove the spark plug.
SPARK PLUG
WRENCH
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SPARK PLUG MAINTENANCE COVER
HANDLE BAR
SPARK PLUG CAP