I use Enya #3 in many 4 stroke engines, because they work ( for a very long time. Also use the Merlin 2011in some for the same reason. The 2001 and 2002 "work" with OBG ,give good idle and allow leaner top end settings. Lately working with the Enya "4 Stroke" plug on the Saito twins. Will see how they work too.