Jim,


The OS A3 is a hot plug; the hottest OS have to offer and so is the previous, no longer available, Tower plug, which was an A3 clone.

The current Tower Power plug is a medium heat plug, similar to the OS #8, the Enya #4 and the Novarossi C-6S.


I don't know which of the two Tower plugs you were referring to, but if it was a late model unit, it is a significantly colder plug than the A3.
You could have leaned the mixture strength quite a bit with it, after changing from the A3.


Barry Williams says the Evo .46 runs better on hot plugs.
I'll take his word for it, even though a medium plug would seem more appropriate for this engine.

Maybe its lower C/R (to make it easier to handle as a beginners' engine) allows this.