HONDA GX25 - Manual (Page 20)

20
Spark plug service
Recommended spark plug:
Never use a spark plug of incorrect heat range.
3.
TOP COVER
5 mm HEX BOLT
CMR5H (NGK)
To ensure proper engine operation, the spark plug must be
properly gapped and free of deposits.
Loosen the 5 mm hex bolt, then remove the top cover.
Do not pull the starter grip and start the engine without the top
cover. There are rotating and hot parts under the cover.
1.