Yamaha Marine Outboards Factory Service / Repair/ Workshop Manual 225G 250B L250B, Page 310Get this manual
IGNITION SYSTEM
INSPECTING THE IGNITION SPARK GAP 8
WARNING
Do not touch any of the connections of the spark gap tester lead wires Do not let sparks leak out of the removed spark plug cap Keep flammable gas or liquids away, since this test can produce sparksInspect: Ignition spark gap Above specification Replace the spark plugBelow specification Inspect the CDI unit output8210