The YS 63S turns out to be a real gem. It is 0.8 oz lighter than the YS 63FZ and 0.6 oz lighter than the Saito 72.



After half a gallon of Powermaster YS 20/20 fuel through it, my YS 63S currently peaks out at 11.9K rpm swinging a Graupner 12x7 prop, so I set my ground rpm at 11.5K (400 rpm on the rich side):



The engine (mounted inverted) can now hold a steady, reliable idle between 1700 and 1900 rpm without onboard glow or glow igniter, as can be seen in this video:

--> [link=http://www.whitetyphoon.com/rc/ys63s/idle.mpg]YS 63S Slooow Idle[/link]

No deadsticks so far (never had a deadstick with a YS). It's all about tuning, folks.