To replace spark plugs..
... with a "10" head, unscrew the two nuts and two bolts securing the engine cover..
...and take it off.
We remove the tip of the high-voltage wire from the candle.
With a high "candle" head "16" with an extension cord, we unscrew the spark plug..
... and take it out of the candle well.
When screwing in the spark plug, turn the socket extension or spark plug wrench by hand, not with a wrench or ratchet, to avoid damage to the threads of the spark plug hole in the cylinder head.
If the candle has not gone along the thread, there will be a strong resistance to rotation. In this case, it is necessary to completely unscrew the candle and, having cleaned the thread, re-wrap it.
Finally tighten the candle to the prescribed torque (see Tightening torques for critical threaded connections).
Overtightening the spark plugs can damage the threads in the spark plug holes in the cylinder head.
Similarly, we check (replace) other spark plugs.