The manual doesn’t tell you the type of sparkplug it is, which is really annoying when you’re at the hardware store.
(it’s a Champion RCJ6Y)

Model Y4GS A18 0001
Engine displacement 51.5 cc
Maximum engine power 1.85 kW
Maximum speed 10000 rpm
Idling speed 2800 rpm
Fuel Tank Capacity 550 ml
Fuel/Oil Mix Ratio 40:1
Chain oil tank capacity 260 ml
Bar Type OREGON 180SDEA095
Bar length 450 mm (18″)
Chain type OREGON 91P061X
Dry Weight (no bar/chain) 5.3 kg
Vibration @ Front handle 8.5 m/s² k=1.5
Vibration @ Front handle 9.3 m/s²
Spark plug gap 0.6-0.7 mm
Spark plug type Torch L8RTF
Champion RCJ6Y
NGK BPMR7A(?)